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Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minutes
#1
A
ajwgator
A
ajwgator
Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minutes
I have a Kohler Command Pro 28 w/Bosch EFI, Spec No. PS-CV745-0004, S/N 3300602011 on a Gravely Promaster 260Z frame. It runs and cuts great for 30-45 minutes and then I get an MIL light. It goes back off after a minute or two then returns to stay on. Continued use results in the engine bogging down and will die if under a load. Reading the flash codes from ECU I get a 34 and 31 (in that order). If I let the unit sit for an hour or so it starts back up fine and operates normally with no MIL light for another 30 minutes or so. The Bosch ECU numbers are P/N 24 584 29, S/N 5000696 and is a 32 pin MSE 1.1 version.
I used the troubleshooting guides in the maintenance manual and realize these code have to do with the TPS sensor and Oxygen Sensor. They both check out OK. When the engine is acting up as described above I can see that the throttle is being held wide open by the governor. I have read a couple of posts concerning similar issues but didn't find anyone that came back to report a good fix for them. When I checked the readings on the TPS sensor I get 945 ohms when full closed and as I rotate the throttle towards full open the reading increases till I get to 1996 ohms but the throttle is not at WOT yet and continuing on towards WOT the reading goes to open (no continuity). Thought that wasn't right so I purchased a new TPS sensor from Kohler. In checking out the new TPS sensor (I haven't installed it) I find that the readings are exactly the same as original TPS above (that is still installed) so I don't think the installed one is causing the problem even though the 34 code is being reported.
Concerning the Oxygen sensor, I removed and reinstalled it after cleaning the tip (it wasn't carbonned up and fins were open) and it is putting out the correct voltages when it reaches operating temperature. So again I don't feel that is causing the problem even though the 31 code is being reported.
I haven't done a TPS Initialization Procedure on the system because of the way the unit starts back up and operates for another 30 minutes or so after sitting. I would think that if ECU has lost the learned setting from the installed TPS sensor it would not start back up and operate fine like it does.
I appreciate anyone's input on this issue because the Kohler dealer in my area say they don't know much about the Bosch EFI systems since Kohler stopped using them 3-4 years ago. Of course they want me to switch it to the Delphi EFI...
Thanks.... in advance....
I have a Kohler Command Pro 28 w/Bosch EFI, Spec No. PS-CV745-0004, S/N 3300602011 on a Gravely Promaster 260Z frame. It runs and cuts great for 30-45 minutes and then I get an MIL light. It goes back off after a minute or two then returns to stay on. Continued use results in the engine bogging down and will die if under a load. Reading the flash codes from ECU I get a 34 and 31 (in that order). If I let the unit sit for an hour or so it starts back up fine and operates normally with no MIL light for another 30 minutes or so. The Bosch ECU numbers are P/N 24 584 29, S/N 5000696 and is a 32 pin MSE 1.1 version.
I used the troubleshooting guides in the maintenance manual and realize these code have to do with the TPS sensor and Oxygen Sensor. They both check out OK. When the engine is acting up as described above I can see that the throttle is being held wide open by the governor. I have read a couple of posts concerning similar issues but didn't find anyone that came back to report a good fix for them. When I checked the readings on the TPS sensor I get 945 ohms when full closed and as I rotate the throttle towards full open the reading increases till I get to 1996 ohms but the throttle is not at WOT yet and continuing on towards WOT the reading goes to open (no continuity). Thought that wasn't right so I purchased a new TPS sensor from Kohler. In checking out the new TPS sensor (I haven't installed it) I find that the readings are exactly the same as original TPS above (that is still installed) so I don't think the installed one is causing the problem even though the 34 code is being reported.
Concerning the Oxygen sensor, I removed and reinstalled it after cleaning the tip (it wasn't carbonned up and fins were open) and it is putting out the correct voltages when it reaches operating temperature. So again I don't feel that is causing the problem even though the 31 code is being reported.
I haven't done a TPS Initialization Procedure on the system because of the way the unit starts back up and operates for another 30 minutes or so after sitting. I would think that if ECU has lost the learned setting from the installed TPS sensor it would not start back up and operate fine like it does.
I appreciate anyone's input on this issue because the Kohler dealer in my area say they don't know much about the Bosch EFI systems since Kohler stopped using them 3-4 years ago. Of course they want me to switch it to the Delphi EFI...
Thanks.... in advance....
#2
I
ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Find the system ground lead for your engine. Check to see if it is connected to the cylinder baffle, a black phospor starter bolt, or has a stainless steel eyelet. If any of this exist you will need terminal upgrade kit. 24 452 01-s Assuming you have the plastic ECU box.
the code 34 has been linked to a faulty ground, but normally also shows code 21. From my understanding it requires cutting off the old terminal and soldering the new terminal eyelet in its place. Cannot just be scotchlok into the wiring harness.
Find the system ground lead for your engine. Check to see if it is connected to the cylinder baffle, a black phospor starter bolt, or has a stainless steel eyelet. If any of this exist you will need terminal upgrade kit. 24 452 01-s Assuming you have the plastic ECU box.
the code 34 has been linked to a faulty ground, but normally also shows code 21. From my understanding it requires cutting off the old terminal and soldering the new terminal eyelet in its place. Cannot just be scotchlok into the wiring harness.
#3
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Thanks for the reply & info ILEngine. I'll check that this morning and will definitely report back my findings for everyone's sake. Concerning the kit number you listed, I have a good assortment of solid copper lugs from my Air Force days that I can crimp & solder on. Is there anything else in that kit that would make it better for me to get the kit? Thanks again.
Thanks for the reply & info ILEngine. I'll check that this morning and will definitely report back my findings for everyone's sake. Concerning the kit number you listed, I have a good assortment of solid copper lugs from my Air Force days that I can crimp & solder on. Is there anything else in that kit that would make it better for me to get the kit? Thanks again.
#4
M
motoman
M
motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
A common theme in auto EFI t-shooting is that wiring is always suspect. Since you have looked at the devices and will look at the ground I would look at the wiring for a possible intermittent short or open (chafed wire touching ground , corroded contacts inside any snap connectors relays, or broken wiring at strain points such as crimps at connectors. The EFI much more sensitive to voltages than non EFI. Since these codes are set after repeated events you may have to use a meter on wire runs (ohms) rather than try to detect while running. Warm up the engine if possible. These are always tricky problems. I'm not sure cleaning the oxy sensor is a good idea. IMO
A common theme in auto EFI t-shooting is that wiring is always suspect. Since you have looked at the devices and will look at the ground I would look at the wiring for a possible intermittent short or open (chafed wire touching ground , corroded contacts inside any snap connectors relays, or broken wiring at strain points such as crimps at connectors. The EFI much more sensitive to voltages than non EFI. Since these codes are set after repeated events you may have to use a meter on wire runs (ohms) rather than try to detect while running. Warm up the engine if possible. These are always tricky problems. I'm not sure cleaning the oxy sensor is a good idea. IMO
#5
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Thanks for the reply and info motorman. I'll be spending some more time on it tomorrow & will definitely use your input. And to ILEngine, my ECU box is plastic. I did make a bit of progress today but I'm not out of the woods yet.
So here is my report after todays troubleshooting and findings. My battery ground lead is connected to a large lug that is bolted to the block about midway up crankcase (not far from the starter). The system ground is connected to that same lug. The bolt is steel and the eyelets are not stainless steel. I took it apart and cleaned the eyelets up with a wire brush and soldered the them. Ohm meter shows good continuity between pin 19 (on 32 pin ECU plug) and grounding lug connection. It was reading good continuity before too but wanted to make sure there wasn't any corrosion under the bolt & eyelets. The service manual wiring diagram shows two ground wires (pin 19 and pin 21) and has a note that states "Two separate 18 AWG wires" but my 32 pin ECU plug does not have a connector in hole for pin 21. Not sure if this could be an issue or not.
My starter bolts are not the black phosphorus bolts. They are definitely steel and one does have a ground on it. It is the chassis ground from the engine block to the mower frame. It does not go into the ECU wiring harness. I also took this ground apart and wire brushed it, soldered the eyelet connection, and made sure there wasn't any corrosion where it connects.
The only other ground on the engine crankcase is on the rectifier-regulator for the alternator. Took it apart and cleaned up like the others and ohm meter shows good continuity from the rectifier-regulator aluminum case to all grounding lug connections and chassis.
The only questionable ground I really found was the muffler itself. The O2 sensor (single wire sensor) is suppose to ground through the muffler according to Grounding note B on the wiring diagram. I could get it to read continuity but I had to really scrape the meter lead pretty hard against the O2 sensor case. The note in the wiring diagram for the O2 sensor goes on to say that "If a slip joint is used, a grounding strap is required". So I went ahead and added a grounding strap around the O2 sensor case with a ground wire and attached it to the same chassis ground connection at the starter bolt.
Got it all back together and took it out for a test run. Good news first, I no longer get a MIL code 34. Bad news is after running for 30 minutes I still am getting a MIL light and the performance goes to crap. The only code that I am getting is 31. I shut it off and let it sit for only 5 minutes and then started it back up. It ran fine again for another (exactly) 30 minutes and same result, MIL code 31.
The service manual has two lines for a 31 code on the "32 pin ECU" system. I don't have a "OBD2" P code reader but one 31 code is for P0174, system too lean; the other is P0321 O2 Sensor Circuit, Shorted to Battery. Each has a note, P0174 has a note 6 which reads "System too Lean used to be O2 Sensor-Shorted to Ground (P0131). P0321 has a note 3 which reads "O2 Sensor Short to Battery diagnostic detection is disabled with SAS fuel-cutoff calibrated out." I have no idea what SAS fuel-cutoff is or if it is calibrated out or not. Anyone have any insight on that?
Well like I said in the beginning of the post (sorry it is so long) I'm not out of the woods yet. Maybe cleaning the O2 sensor wasn't a good idea like motorman said but it was too late by that time. I still think it may be OK but I don't know for sure. I guess tomorrow I will go ahead and bite the bullet and disconnect all the loads and belts off the engine and do a TPS Initialization Procedure on it. Code 31 does say Fuel Mixture or Oxygen Sensor, and System too lean along with Oxygen sensor not sending expected voltage to ECU. I'll do this along with checking the relay connections and look the wiring over a bit more.
Still open to any and all suggestions from you guys too. My brain is about tapped out right now.
Thanks for the reply and info motorman. I'll be spending some more time on it tomorrow & will definitely use your input. And to ILEngine, my ECU box is plastic. I did make a bit of progress today but I'm not out of the woods yet.
So here is my report after todays troubleshooting and findings. My battery ground lead is connected to a large lug that is bolted to the block about midway up crankcase (not far from the starter). The system ground is connected to that same lug. The bolt is steel and the eyelets are not stainless steel. I took it apart and cleaned the eyelets up with a wire brush and soldered the them. Ohm meter shows good continuity between pin 19 (on 32 pin ECU plug) and grounding lug connection. It was reading good continuity before too but wanted to make sure there wasn't any corrosion under the bolt & eyelets. The service manual wiring diagram shows two ground wires (pin 19 and pin 21) and has a note that states "Two separate 18 AWG wires" but my 32 pin ECU plug does not have a connector in hole for pin 21. Not sure if this could be an issue or not.
My starter bolts are not the black phosphorus bolts. They are definitely steel and one does have a ground on it. It is the chassis ground from the engine block to the mower frame. It does not go into the ECU wiring harness. I also took this ground apart and wire brushed it, soldered the eyelet connection, and made sure there wasn't any corrosion where it connects.
The only other ground on the engine crankcase is on the rectifier-regulator for the alternator. Took it apart and cleaned up like the others and ohm meter shows good continuity from the rectifier-regulator aluminum case to all grounding lug connections and chassis.
The only questionable ground I really found was the muffler itself. The O2 sensor (single wire sensor) is suppose to ground through the muffler according to Grounding note B on the wiring diagram. I could get it to read continuity but I had to really scrape the meter lead pretty hard against the O2 sensor case. The note in the wiring diagram for the O2 sensor goes on to say that "If a slip joint is used, a grounding strap is required". So I went ahead and added a grounding strap around the O2 sensor case with a ground wire and attached it to the same chassis ground connection at the starter bolt.
Got it all back together and took it out for a test run. Good news first, I no longer get a MIL code 34. Bad news is after running for 30 minutes I still am getting a MIL light and the performance goes to crap. The only code that I am getting is 31. I shut it off and let it sit for only 5 minutes and then started it back up. It ran fine again for another (exactly) 30 minutes and same result, MIL code 31.
The service manual has two lines for a 31 code on the "32 pin ECU" system. I don't have a "OBD2" P code reader but one 31 code is for P0174, system too lean; the other is P0321 O2 Sensor Circuit, Shorted to Battery. Each has a note, P0174 has a note 6 which reads "System too Lean used to be O2 Sensor-Shorted to Ground (P0131). P0321 has a note 3 which reads "O2 Sensor Short to Battery diagnostic detection is disabled with SAS fuel-cutoff calibrated out." I have no idea what SAS fuel-cutoff is or if it is calibrated out or not. Anyone have any insight on that?
Well like I said in the beginning of the post (sorry it is so long) I'm not out of the woods yet. Maybe cleaning the O2 sensor wasn't a good idea like motorman said but it was too late by that time. I still think it may be OK but I don't know for sure. I guess tomorrow I will go ahead and bite the bullet and disconnect all the loads and belts off the engine and do a TPS Initialization Procedure on it. Code 31 does say Fuel Mixture or Oxygen Sensor, and System too lean along with Oxygen sensor not sending expected voltage to ECU. I'll do this along with checking the relay connections and look the wiring over a bit more.
Still open to any and all suggestions from you guys too. My brain is about tapped out right now.
#6
I
ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
You don't say how many hours are on your mower. But Kohler says that the O2 sensor may start to fail above 700 hours. So you could have a sensor issue or possibly the fuel pump isn't working properly after it gets hot causing low fuel pressure, leading to the lean run code 31.
Some of the problems on these engines just can't be determined very easily without the laptop software.
You don't say how many hours are on your mower. But Kohler says that the O2 sensor may start to fail above 700 hours. So you could have a sensor issue or possibly the fuel pump isn't working properly after it gets hot causing low fuel pressure, leading to the lean run code 31.
Some of the problems on these engines just can't be determined very easily without the laptop software.
#7
M
motoman
M
motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
gator, I found Kohler site with their diagnostic software for sale $95. It looks very good at this price. I did not see what platform it uses, maybe a laptop . If your time is worth anything this might be a good way to go. Also a 4 part series on youtube shows how it works.
gator, I found Kohler site with their diagnostic software for sale $95. It looks very good at this price. I did not see what platform it uses, maybe a laptop . If your time is worth anything this might be a good way to go. Also a 4 part series on youtube shows how it works.
#8
I
ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
There is only one problem with the $95 software sale. It doesn't come with the interface cable which is an additional $245.
There is only one problem with the $95 software sale. It doesn't come with the interface cable which is an additional $245.
#9
M
motoman
M
motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Mr IL ENG should know, but is this like the HP printer ink which is sole sourced and meant to recover loss on sale of printers? I am not a computer nerd, but interface cables can often be created. Don't know myself. So IL ENG what are the connectors on each end of the cable, if you know. And although costly what is the average shop cost for a couple hours and some parts? Maybe it still makes sense? And IL ENG, you don't run this SW?
Mr IL ENG should know, but is this like the HP printer ink which is sole sourced and meant to recover loss on sale of printers? I am not a computer nerd, but interface cables can often be created. Don't know myself. So IL ENG what are the connectors on each end of the cable, if you know. And although costly what is the average shop cost for a couple hours and some parts? Maybe it still makes sense? And IL ENG, you don't run this SW?
#10
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Well I didn't get to do the TPS Initialization Procedure today as a higher priority got put ahead of the list. I did read the replies before I left this morning and have been giving a lot of thought while working today. ILEngine, your statement about the possibility of the fuel pump not working properly is something that I really never considered since it has always started back up fine. The more I think about it the more sense it makes. I always hear it run when I turn the key and also hear the fuel pressure regular dumping the excess fuel pressure back into the fuel tank so I had pretty much ruled that out. After you bringing it up I did a lot of thinking. It is running continuously whenever the engine is running and maybe after 30 minutes it is overheating, slows down and can't deliver enough fuel to meet the demand, the ECU tries it best to correct the situation but can't and turns the MIL. When the engine finally quits or is shut off, the fuel in the lines would cool the pump back down pretty fast. I start it back up and things seem fine again but after another 30 minutes it starts acting up all over again. It would easy to check out by just putting a tee in the fuel line after it leaves the regulator and before it get to the injectors and hooking a gage to it. I could monitor the pressure and see what is going on when it start acting up.
Concerning the age/hours of the mower, the mower has some age on it but I can't find the exact year it is. Its a Gravely Promaster 260Z, Model 992048, s/n 000161. I picked it up used and previous owner had replaced the engine a couple of years ago with the same that came on it. The engine has 200 hours on it. The specs on it are in my first post that started this thread. I can't seem to find a place to interpret the numbers into what exact year they were manufactured. I think that the muffler & the O2 sensor came off of the original engine unless Kohler supplies new ones with a power plant change out. I just don't know for sure but as I posted in the beginning the O2 sensor is checking out when I check the voltage readings it puts out after I get it to temperature. I'm just not able to check it while it is running. I know it is not shorted to ground or battery and is only just reporting what it is reading and it doesn't match what the ECU wants to see from a properly running engine. So the ECU tries to correct it with timing or fuel volume. If the fuel pump is acting up and doesn't deliver enough fuel to meet the demand, well there you go... bogs down, loss of power, popping noise in the air cleaner, all the results the efforts that the ECU is trying to correct what it sees wrong from the data being sent to it. JMO but O2 sensors are nothing but a chemical battery that produces a small voltage reading. Nothing in them to fail mechanically but if can be shorted out or an open but that is usually because of mishandling and not from just sitting there in the exhaust system.
Motoman, I didn't find the $95 software. Was that from Kohler or from somewhere else? I have seen the 4 part youtube before and if that is the same software you are referring to, its not worth it to me because there is way too much "other stuff" in it that really isn't needed IMO. I'm not in business here, don't need to keep up customer info, maintenance history, engine numbers, ect... All one really needs is an OBD2 code reader for the P codes and that it. You know like we have for cars today. Of course ILEngine's info about the software not having the interface cable is pretty good info too. I don't think you should jump on him like you did. He isn't trying to "run this SW" like you said (whatever that means). The way I see it he is only sharing information and passing on knowledge to anyone who asks. I for one appreciate any and all input to problems I'm having and trying to find answers. Its great to be able to do this and I think it is "priceless" information one can't buy anywhere.
Well I gone on too long again. I will report back after my next maintenance session. Again any input is always welcome and I really do appreciate it!
You don't say how many hours are on your mower. But Kohler says that the O2 sensor may start to fail above 700 hours. So you could have a sensor issue or possibly the fuel pump isn't working properly after it gets hot causing low fuel pressure, leading to the lean run code 31.
Some of the problems on these engines just can't be determined very easily without the laptop software.
gator, I found Kohler site with their diagnostic software for sale $95. It looks very good at this price. I did not see what platform it uses, maybe a laptop . If your time is worth anything this might be a good way to go. Also a 4 part series on youtube shows how it works.
Well I didn't get to do the TPS Initialization Procedure today as a higher priority got put ahead of the list. I did read the replies before I left this morning and have been giving a lot of thought while working today. ILEngine, your statement about the possibility of the fuel pump not working properly is something that I really never considered since it has always started back up fine. The more I think about it the more sense it makes. I always hear it run when I turn the key and also hear the fuel pressure regular dumping the excess fuel pressure back into the fuel tank so I had pretty much ruled that out. After you bringing it up I did a lot of thinking. It is running continuously whenever the engine is running and maybe after 30 minutes it is overheating, slows down and can't deliver enough fuel to meet the demand, the ECU tries it best to correct the situation but can't and turns the MIL. When the engine finally quits or is shut off, the fuel in the lines would cool the pump back down pretty fast. I start it back up and things seem fine again but after another 30 minutes it starts acting up all over again. It would easy to check out by just putting a tee in the fuel line after it leaves the regulator and before it get to the injectors and hooking a gage to it. I could monitor the pressure and see what is going on when it start acting up.
Concerning the age/hours of the mower, the mower has some age on it but I can't find the exact year it is. Its a Gravely Promaster 260Z, Model 992048, s/n 000161. I picked it up used and previous owner had replaced the engine a couple of years ago with the same that came on it. The engine has 200 hours on it. The specs on it are in my first post that started this thread. I can't seem to find a place to interpret the numbers into what exact year they were manufactured. I think that the muffler & the O2 sensor came off of the original engine unless Kohler supplies new ones with a power plant change out. I just don't know for sure but as I posted in the beginning the O2 sensor is checking out when I check the voltage readings it puts out after I get it to temperature. I'm just not able to check it while it is running. I know it is not shorted to ground or battery and is only just reporting what it is reading and it doesn't match what the ECU wants to see from a properly running engine. So the ECU tries to correct it with timing or fuel volume. If the fuel pump is acting up and doesn't deliver enough fuel to meet the demand, well there you go... bogs down, loss of power, popping noise in the air cleaner, all the results the efforts that the ECU is trying to correct what it sees wrong from the data being sent to it. JMO but O2 sensors are nothing but a chemical battery that produces a small voltage reading. Nothing in them to fail mechanically but if can be shorted out or an open but that is usually because of mishandling and not from just sitting there in the exhaust system.
Motoman, I didn't find the $95 software. Was that from Kohler or from somewhere else? I have seen the 4 part youtube before and if that is the same software you are referring to, its not worth it to me because there is way too much "other stuff" in it that really isn't needed IMO. I'm not in business here, don't need to keep up customer info, maintenance history, engine numbers, ect... All one really needs is an OBD2 code reader for the P codes and that it. You know like we have for cars today. Of course ILEngine's info about the software not having the interface cable is pretty good info too. I don't think you should jump on him like you did. He isn't trying to "run this SW" like you said (whatever that means). The way I see it he is only sharing information and passing on knowledge to anyone who asks. I for one appreciate any and all input to problems I'm having and trying to find answers. Its great to be able to do this and I think it is "priceless" information one can't buy anywhere.
Well I gone on too long again. I will report back after my next maintenance session. Again any input is always welcome and I really do appreciate it!
#11
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Forgot one thing... I found out what SAS fuel-cutoff is. It is a system used on engines that are dual fuel, LP gas & Petro. Used a lot in Europe. When using LP gas fuel, the ECU does not use the data reading from the O2 sensor. That is what "calibrated out" means.
Forgot one thing... I found out what SAS fuel-cutoff is. It is a system used on engines that are dual fuel, LP gas & Petro. Used a lot in Europe. When using LP gas fuel, the ECU does not use the data reading from the O2 sensor. That is what "calibrated out" means.
#12
I
ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Gator, from your serial number the engine was made in 2003. unfortunately they are not using a standard OBD2 connector.
That 4 pin diagnostics plug on one end with the special circuit box to rs-232 serial plug contains special components to split out the various signals, and also to prevent 12 volts from reaching the tech's computer. Then since modern computers don't have serial ports, that cable then gets plugged into a serial to USB conversion cable. At least Kohler is using standard P OBD2 codes which is more than I can say about some of the other small engine manufacturers.
My Kohler distributor told us once that they would supply use the software for free, but we still had to buy the cable. Could that cable be made cheaper than what they want for it. I am sure it could be, Just need to figure out what is inside the box at the end of the cable with the four pin connector. We were even told to use an older laptop to run the software, because Kohler was having problems with electric clutches and the like causing voltage spikes and cooking ECU's when they were turned off. Have even heard of one case where a tech was test running an engine and shut off the pto and it cooked the ECU and the tech's laptop due to a voltage spike.
Gator, from your serial number the engine was made in 2003. unfortunately they are not using a standard OBD2 connector.
That 4 pin diagnostics plug on one end with the special circuit box to rs-232 serial plug contains special components to split out the various signals, and also to prevent 12 volts from reaching the tech's computer. Then since modern computers don't have serial ports, that cable then gets plugged into a serial to USB conversion cable. At least Kohler is using standard P OBD2 codes which is more than I can say about some of the other small engine manufacturers.
My Kohler distributor told us once that they would supply use the software for free, but we still had to buy the cable. Could that cable be made cheaper than what they want for it. I am sure it could be, Just need to figure out what is inside the box at the end of the cable with the four pin connector. We were even told to use an older laptop to run the software, because Kohler was having problems with electric clutches and the like causing voltage spikes and cooking ECU's when they were turned off. Have even heard of one case where a tech was test running an engine and shut off the pto and it cooked the ECU and the tech's laptop due to a voltage spike.
#13
M
motoman
M
motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
gator, The word "run" is a harmless verb and I think IL ENG knows I was merely inquiring. His answer does clarify some of the interface cable questions. I believe you could check the O sensor outside the tractor circuit by threading a metal plate , installing the sensor and heating it slowing while observing the voltage outputs. The manual may give you voltage values at various temps. Depending on the O sensor cost it may not be worth it.
Edit: The cable described may indeed also be reasonably priced after looking at various other interface cables on line. If commercial , seems like the value would be there if it could keep " a fleet" running.
gator, The word "run" is a harmless verb and I think IL ENG knows I was merely inquiring. His answer does clarify some of the interface cable questions. I believe you could check the O sensor outside the tractor circuit by threading a metal plate , installing the sensor and heating it slowing while observing the voltage outputs. The manual may give you voltage values at various temps. Depending on the O sensor cost it may not be worth it.
Edit: The cable described may indeed also be reasonably priced after looking at various other interface cables on line. If commercial , seems like the value would be there if it could keep " a fleet" running.
#14
I
ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Motoman, I understand what you were getting at, but without face to face your post came across as somewhat snippy. But I have gotten snippy with a few people on here also, and it all came out in the wash. I think we have known each other for long enough to get past the little misunderstanding, and give the best advice that we can give.
Unlike auto makers, the small engine manufacturers, and the corresponding mower that goes with it haven't came out with a standard troubleshooting plug for their EFI systems. So everybody had their own system. The kohler software is like $299.99, and the briggs software is $160, but does offer a quick scan unit for less than that. then their are other companies like Subara that use EFI but don't have diagnostic systems.
Motoman, I understand what you were getting at, but without face to face your post came across as somewhat snippy. But I have gotten snippy with a few people on here also, and it all came out in the wash. I think we have known each other for long enough to get past the little misunderstanding, and give the best advice that we can give.
Unlike auto makers, the small engine manufacturers, and the corresponding mower that goes with it haven't came out with a standard troubleshooting plug for their EFI systems. So everybody had their own system. The kohler software is like $299.99, and the briggs software is $160, but does offer a quick scan unit for less than that. then their are other companies like Subara that use EFI but don't have diagnostic systems.
#15
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motoman
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motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
IL ENG, Thanks, "snippiness" never intended on this or any other response from me . Glad all is well. Appreciate your professional slant. motoman
IL ENG, Thanks, "snippiness" never intended on this or any other response from me . Glad all is well. Appreciate your professional slant. motoman
#16
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ajwgator
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ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Thanks for the year info on my engine ILEngine. Definitely older than the previous owner said it was. I bought it last year and at that time he said it was a year or so old. No biggie here as far as I'm concerned... it is a strong engine and runs great (at least for 30 minutes each time... for now... lol). Do you have a online source that can interpret the serial numbers? I thought at one time I was able to do it on Kohler's site but I couldn't find it there the other night.
As for the 4 pin connector, the way I see on the wiring diagram there is only one wire in it that is a data line. That is the Diagnostic K-Line which is connected to pin 17 of the ECU. The other 3, TPS Initialization, +12 volts, & ground wouldn't have any data. As for splitting the signals, I would think that the chip in the ECU would be doing that all the time is carrying out its functions and that same data is sort of "streamed" continuously and available to be read by software through the one diagnostic K-Line. That "special circuit" black box might be a head fake to justify the big price of the interface cable. Think about it for a minute... just look at out phone lines and how much "data" is being sent to you and I every second to our computers and that is only 2 wires....
As I stated before, to me its not worth it especially when hearing about the cases of blowing ECU's. A lot of times these "tools" can cause us to overlook the basics that are not being monitored in the hopes that they will "always" tell us what the problem is and what is needed to fix it. Take the fuel pump for instance, nothing in the ECU is monitoring the fuel pressure. When the pressure is insufficient to supply an adequate flow demand that the ECU is sending to the injectors the RPMs drop. The ECU see that from the speed sensor because it doesn't match what the TPS & O2 says it should be and then ends up increasing the time the injectors are open and/or changing the timing in an attempt to correct the performance back to what the mapping in the ECU says it is suppose to be. It fails because the nothing is there to increase the fuel pressure because the ECU is programed that it is always 39 psi no matter what. The MIL is triggered because the ECU does not see the readings that match the mapped settings it is programed to look for.
I didn't get back the engine today and it may have to wait another. Tomorrow is the wife's Bday and I don't want to end up in the dog house. I have to set up a test gage and connection but will know for sure if there is a fuel pressure problem causing this issue. Make perfect sense to me after you mentioned and as I said thought about it a lot. Every electric motor I have every fooled with heats up when they run and if the bearings or bushing are worn or dry that causes more drag, then more heat, then finally to the point they are turning fast enough. They will even get to the point they won't start any more. That's all the fuel pump is... and electric motor.
Thanks again for the input and thought provoking points.
Thanks for the year info on my engine ILEngine. Definitely older than the previous owner said it was. I bought it last year and at that time he said it was a year or so old. No biggie here as far as I'm concerned... it is a strong engine and runs great (at least for 30 minutes each time... for now... lol). Do you have a online source that can interpret the serial numbers? I thought at one time I was able to do it on Kohler's site but I couldn't find it there the other night.
As for the 4 pin connector, the way I see on the wiring diagram there is only one wire in it that is a data line. That is the Diagnostic K-Line which is connected to pin 17 of the ECU. The other 3, TPS Initialization, +12 volts, & ground wouldn't have any data. As for splitting the signals, I would think that the chip in the ECU would be doing that all the time is carrying out its functions and that same data is sort of "streamed" continuously and available to be read by software through the one diagnostic K-Line. That "special circuit" black box might be a head fake to justify the big price of the interface cable. Think about it for a minute... just look at out phone lines and how much "data" is being sent to you and I every second to our computers and that is only 2 wires....
As I stated before, to me its not worth it especially when hearing about the cases of blowing ECU's. A lot of times these "tools" can cause us to overlook the basics that are not being monitored in the hopes that they will "always" tell us what the problem is and what is needed to fix it. Take the fuel pump for instance, nothing in the ECU is monitoring the fuel pressure. When the pressure is insufficient to supply an adequate flow demand that the ECU is sending to the injectors the RPMs drop. The ECU see that from the speed sensor because it doesn't match what the TPS & O2 says it should be and then ends up increasing the time the injectors are open and/or changing the timing in an attempt to correct the performance back to what the mapping in the ECU says it is suppose to be. It fails because the nothing is there to increase the fuel pressure because the ECU is programed that it is always 39 psi no matter what. The MIL is triggered because the ECU does not see the readings that match the mapped settings it is programed to look for.
I didn't get back the engine today and it may have to wait another. Tomorrow is the wife's Bday and I don't want to end up in the dog house. I have to set up a test gage and connection but will know for sure if there is a fuel pressure problem causing this issue. Make perfect sense to me after you mentioned and as I said thought about it a lot. Every electric motor I have every fooled with heats up when they run and if the bearings or bushing are worn or dry that causes more drag, then more heat, then finally to the point they are turning fast enough. They will even get to the point they won't start any more. That's all the fuel pump is... and electric motor.
Thanks again for the input and thought provoking points.
#17
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ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Today I was able to tee a pressure gage into the fuel line. I installed the tee in fuel line after the pressure regulator before the fuel reaches the injectors. I bled the system a couple of times to make sure and then started the mower up. As always it ran fine and fuel pressure was registering 41 psi and no MIL. I did some mowing to do a good test with a normal load on everything. All was well just like before but after almost 30 minutes pasted I noticed the fuel pressure starting to fluctuate down to 30 psi and then raise back up. It keep on doing that but would go lower each time. When it reached 20 psi the MIL came on and the engine power dropped off a good bit. I disengaged the PTO and headed back to the garage. When I got back in the pressure was staying at 20 psi and I could tell the ECU was trying its best to compensate by changing the timing because I heard popping in the air cleaner. I went ahead and shut it off then and let it sit for about 10 minutes. When I started it back up the fuel pressure as back to 41 psi and the engine was running fine again. I decided to run it more and began cutting some more but by this time it was getting dark and I ran out of time to make sure I duplicated the results a second time. I feel certain now that it is the fuel pump that is causing the ECU to report the MIL codes but I will duplicated the problem one more time to make sure tomorrow. Then I'll pull the fuel pump and pressure regulator off the mower and give them a good inspection.
I really want to thank everyone for all the input that you have provided me. And a big THANK You to ILEngine for pointing me to the possibility of it being a fuel pump or fuel pressure problem. I'll report back once all is finalized and settled to make sure this issue has a definite fix and so this tread can be a help to others in the future.
Today I was able to tee a pressure gage into the fuel line. I installed the tee in fuel line after the pressure regulator before the fuel reaches the injectors. I bled the system a couple of times to make sure and then started the mower up. As always it ran fine and fuel pressure was registering 41 psi and no MIL. I did some mowing to do a good test with a normal load on everything. All was well just like before but after almost 30 minutes pasted I noticed the fuel pressure starting to fluctuate down to 30 psi and then raise back up. It keep on doing that but would go lower each time. When it reached 20 psi the MIL came on and the engine power dropped off a good bit. I disengaged the PTO and headed back to the garage. When I got back in the pressure was staying at 20 psi and I could tell the ECU was trying its best to compensate by changing the timing because I heard popping in the air cleaner. I went ahead and shut it off then and let it sit for about 10 minutes. When I started it back up the fuel pressure as back to 41 psi and the engine was running fine again. I decided to run it more and began cutting some more but by this time it was getting dark and I ran out of time to make sure I duplicated the results a second time. I feel certain now that it is the fuel pump that is causing the ECU to report the MIL codes but I will duplicated the problem one more time to make sure tomorrow. Then I'll pull the fuel pump and pressure regulator off the mower and give them a good inspection.
I really want to thank everyone for all the input that you have provided me. And a big THANK You to ILEngine for pointing me to the possibility of it being a fuel pump or fuel pressure problem. I'll report back once all is finalized and settled to make sure this issue has a definite fix and so this tread can be a help to others in the future.
#18
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ajwgator
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ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Update on findings from my last post. I ran the mower again and as before it preformed just fine for 30 minutes. At about the 25 minute mark is when I observed the fuel pressure starting to fluctuate. It would drop to 30 psi and come back up to 41 psi. It did this a couple of times and then started getting lower and wouldn't come back up. After passing the 30 minute mark it just continued to get worse. The MIL light came on and the ECU was doing all it knows how to do trying to correct the performance of the engine. I parked the mower and pulled the throttle back to idle and just watched. When the fuel pressure dropped to 5 psi there wasn't enough fuel flow through the injectors to keep the engine running and it just died.
I let things cool off a bit and then proceeded to remove the fuel pump and regulator. Unfortunately this didn't reveal anything obviously wrong. The regulator is functioning well and doing its job. The fuel pump appears fine externally. The electrical connections were tight, no corrosion, and no evidence or signs of overheating. So now we have it, after 30 minutes the fuel pump is definitely seizing up internally as evidenced from the pressure readings.
Time to get a new one! Damn those things must have gold in them..... $199.00.... ! Would you stick with OEM or would you be trying to find a good quality after market fuel pump? I've found an after market pump that is almost identical in visual appearance but it is for a Ford diesel. I think it wouldn't matter what type of fuel it is pumping but I haven't found any good specs on it as of yet. The cost is significantly less than the OEM price. Open for comments and suggestions here.... Thanks in advance!
Update on findings from my last post. I ran the mower again and as before it preformed just fine for 30 minutes. At about the 25 minute mark is when I observed the fuel pressure starting to fluctuate. It would drop to 30 psi and come back up to 41 psi. It did this a couple of times and then started getting lower and wouldn't come back up. After passing the 30 minute mark it just continued to get worse. The MIL light came on and the ECU was doing all it knows how to do trying to correct the performance of the engine. I parked the mower and pulled the throttle back to idle and just watched. When the fuel pressure dropped to 5 psi there wasn't enough fuel flow through the injectors to keep the engine running and it just died.
I let things cool off a bit and then proceeded to remove the fuel pump and regulator. Unfortunately this didn't reveal anything obviously wrong. The regulator is functioning well and doing its job. The fuel pump appears fine externally. The electrical connections were tight, no corrosion, and no evidence or signs of overheating. So now we have it, after 30 minutes the fuel pump is definitely seizing up internally as evidenced from the pressure readings.
Time to get a new one! Damn those things must have gold in them..... $199.00.... ! Would you stick with OEM or would you be trying to find a good quality after market fuel pump? I've found an after market pump that is almost identical in visual appearance but it is for a Ford diesel. I think it wouldn't matter what type of fuel it is pumping but I haven't found any good specs on it as of yet. The cost is significantly less than the OEM price. Open for comments and suggestions here.... Thanks in advance!
#19
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pauly50
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pauly50
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
sounds like your fuel pressure pump is loosing pressure after that 30 minute run time , when it gets hot the pressure drops to below 25 psi or lower , runs very poorly , stops , can re-start after 5 minutes or so and the efi system cannot lengthen the pulse width to compensate ( minimum adaption limit exceeded) and the o2 sensor is sensing the excess air ( lean ) I have seen this very problem in kohler efi mt 26 ghs walker - replace your fuel pressure pump and filter
system fuel pressure should be 39 psi
you can test this by installing fuel pressure gauge at the schrader connection and running engine at full noise with bales running , keep watchin and listen for when the engine starts running poorly , check the fuel pressure gauge , it will be dropping below 25 psi or more and almost stalling and have no power
give it go
cheers hope this helps
pauly50
sounds like your fuel pressure pump is loosing pressure after that 30 minute run time , when it gets hot the pressure drops to below 25 psi or lower , runs very poorly , stops , can re-start after 5 minutes or so and the efi system cannot lengthen the pulse width to compensate ( minimum adaption limit exceeded) and the o2 sensor is sensing the excess air ( lean ) I have seen this very problem in kohler efi mt 26 ghs walker - replace your fuel pressure pump and filter
system fuel pressure should be 39 psi
you can test this by installing fuel pressure gauge at the schrader connection and running engine at full noise with bales running , keep watchin and listen for when the engine starts running poorly , check the fuel pressure gauge , it will be dropping below 25 psi or more and almost stalling and have no power
give it go
cheers hope this helps
pauly50
#20
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motoman
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motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
If it is not oem I would not touch an online identically-looking unit. OEM should have sourced a better product. Auto pumps and regulators fail , but not in great numbers (old memories). My experience was if they don't fail near new they go on and on. I have a 1985 Pontiac with its original regulator (45 psi) , and the pump which replaced the new one after it failed. Still running strong. These are not rocket science. I would try a Taiwan, Canada, Australia etc not mainland China.
If it is not oem I would not touch an online identically-looking unit. OEM should have sourced a better product. Auto pumps and regulators fail , but not in great numbers (old memories). My experience was if they don't fail near new they go on and on. I have a 1985 Pontiac with its original regulator (45 psi) , and the pump which replaced the new one after it failed. Still running strong. These are not rocket science. I would try a Taiwan, Canada, Australia etc not mainland China.
#21
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ajwgator
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ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Pauly50 it helps a lot and glad to hear that someone else has experienced this same problem. I was glad to see you use terms "minimum adaptation limit exceeded" because I had been struggling to really understand what that meant when I read the code meanings in the manuals. I had first went to the TPS sensor (see the first post of the thread) and the readings on the new one were exactly the same as the original one (that was & still installed) so I didn't change it. ILEngine pointed me towards maybe a fuel pump issue which I hadn't even considered before that. I have been posting my experiences & findings to document and help others out here in the future. I am definitely going to change the fuel pump and the filter too.
I'm now trying to get a consensus from others here about using an OEM replacement or better priced (lower) alternatives.
Thanks motorman. Do you know where I might find the specs of (liters per minute or gals per hr & max pressure output) the OEM fuel pump that Kohler uses? Some of the alternative pumps I have found list pressure close to max of 100 psi and other just say high pressure pumps. Since the fuel pressure regulator after the pump limits the pressure when operating to 39 psi, I'm thinking that 100 psi pump output is quite a bit and maybe too much. Do you think the same or does it really matter as long as the regulator can handle it?
sounds like your fuel pressure pump is loosing pressure after that 30 minute run time , when it gets hot the pressure drops to below 25 psi or lower , runs very poorly , stops , can re-start after 5 minutes or so and the efi system cannot lengthen the pulse width to compensate ( minimum adaption limit exceeded) and the o2 sensor is sensing the excess air ( lean ) I have seen this very problem in kohler efi mt 26 ghs walker - replace your fuel pressure pump and filter
system fuel pressure should be 39 psi
you can test this by installing fuel pressure gauge at the schrader connection and running engine at full noise with bales running , keep watchin and listen for when the engine starts running poorly , check the fuel pressure gauge , it will be dropping below 25 psi or more and almost stalling and have no power
Pauly50 it helps a lot and glad to hear that someone else has experienced this same problem. I was glad to see you use terms "minimum adaptation limit exceeded" because I had been struggling to really understand what that meant when I read the code meanings in the manuals. I had first went to the TPS sensor (see the first post of the thread) and the readings on the new one were exactly the same as the original one (that was & still installed) so I didn't change it. ILEngine pointed me towards maybe a fuel pump issue which I hadn't even considered before that. I have been posting my experiences & findings to document and help others out here in the future. I am definitely going to change the fuel pump and the filter too.
I'm now trying to get a consensus from others here about using an OEM replacement or better priced (lower) alternatives.
If it is not oem I would not touch an online identically-looking unit. OEM should have sourced a better product. Auto pumps and regulators fail , but not in great numbers (old memories). My experience was if they don't fail near new they go on and on. I have a 1985 Pontiac with its original regulator (45 psi) , and the pump which replaced the new one after it failed. Still running strong. These are not rocket science. I would try a Taiwan, Canada, Australia etc not mainland China.
Thanks motorman. Do you know where I might find the specs of (liters per minute or gals per hr & max pressure output) the OEM fuel pump that Kohler uses? Some of the alternative pumps I have found list pressure close to max of 100 psi and other just say high pressure pumps. Since the fuel pressure regulator after the pump limits the pressure when operating to 39 psi, I'm thinking that 100 psi pump output is quite a bit and maybe too much. Do you think the same or does it really matter as long as the regulator can handle it?
#22
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motoman
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motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Hopefully IL ENG will respond with specifics. My knowledge is only general. I think you are right to be concerned about "just any" pump. Although the reg "should" be key and provide the pressure the injectors want , with so many later (and higher pressure ) systems you could overwhelm the regulator. I know my 85 PONT wants about 45 psi ( I think), my old Audi wanted 80 (I think) and the current direct injection engines want (?1000). I would grab any Japan sourced part. Sorry cannot provide more. Might look into bike pumps.
Hopefully IL ENG will respond with specifics. My knowledge is only general. I think you are right to be concerned about "just any" pump. Although the reg "should" be key and provide the pressure the injectors want , with so many later (and higher pressure ) systems you could overwhelm the regulator. I know my 85 PONT wants about 45 psi ( I think), my old Audi wanted 80 (I think) and the current direct injection engines want (?1000). I would grab any Japan sourced part. Sorry cannot provide more. Might look into bike pumps.
#23
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ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
From what I can dig up the bosch injection system which would be your system, has a minimum rating of 25 liters/hour at 39 psi. the newer ECH system has a minimum rating of 13.5 liters/hr at 39 psi. Something that may need to be verified prior to confirming the injection pump is bad, is to make sure the lift pump is putting a steady flow of fuel to the injection pump. The older systems used an electric lift pump, and the newer systems use a mechanical, or electric lift pump.
From what I can dig up the bosch injection system which would be your system, has a minimum rating of 25 liters/hour at 39 psi. the newer ECH system has a minimum rating of 13.5 liters/hr at 39 psi. Something that may need to be verified prior to confirming the injection pump is bad, is to make sure the lift pump is putting a steady flow of fuel to the injection pump. The older systems used an electric lift pump, and the newer systems use a mechanical, or electric lift pump.
#24
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ajwgator
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ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
I do believe I have a bosch injection system but not 100% certain, but as far as I can tell I don't have a lift pump in the system at all. The fuel lines on the mower extend down into fuel tank to pull the fuel from the bottom of each tank. The lines then to a manual selector valve (left or right tank),from there through the fuel filter, on to the electric fuel pump, to the fuel pressure regulator, then to an additional fuel filter (I think it has been added by previous owner), and finally to the injector manifold.
Concerning the pressures, yes the 25 lph @39 psi is what is required for proper operation of the engines with EFI systems, but I was trying to find out what pressure the electric fuel pump puts out before being regulated. Any excess pressure is bled off and sent back to which ever fuel tank is selected through the manual selector valve.
What I'm trying to find out is the maximum pressure the OEM electric fuel pump produces before the output is regulated by the fuel pressure regulator. For the sake of discussion, if the OEM fuel pump max press is 50 psi and I replace it with an alternative brand but its max press is 100 psi, would this cause problems such as overwhelming the fuel pressure regulator? (I may be worrying too much) I really hate having to pay $200 for an OEM fuel pump when I have found new high pressure electric fuel pumps for a third of that price.
Hope that better explains what & why I am trying to find out.
From what I can dig up the bosch injection system which would be your system, has a minimum rating of 25 liters/hour at 39 psi. the newer ECH system has a minimum rating of 13.5 liters/hr at 39 psi. Something that may need to be verified prior to confirming the injection pump is bad, is to make sure the lift pump is putting a steady flow of fuel to the injection pump. The older systems used an electric lift pump, and the newer systems use a mechanical, or electric lift pump.
I do believe I have a bosch injection system but not 100% certain, but as far as I can tell I don't have a lift pump in the system at all. The fuel lines on the mower extend down into fuel tank to pull the fuel from the bottom of each tank. The lines then to a manual selector valve (left or right tank),from there through the fuel filter, on to the electric fuel pump, to the fuel pressure regulator, then to an additional fuel filter (I think it has been added by previous owner), and finally to the injector manifold.
Concerning the pressures, yes the 25 lph @39 psi is what is required for proper operation of the engines with EFI systems, but I was trying to find out what pressure the electric fuel pump puts out before being regulated. Any excess pressure is bled off and sent back to which ever fuel tank is selected through the manual selector valve.
What I'm trying to find out is the maximum pressure the OEM electric fuel pump produces before the output is regulated by the fuel pressure regulator. For the sake of discussion, if the OEM fuel pump max press is 50 psi and I replace it with an alternative brand but its max press is 100 psi, would this cause problems such as overwhelming the fuel pressure regulator? (I may be worrying too much) I really hate having to pay $200 for an OEM fuel pump when I have found new high pressure electric fuel pumps for a third of that price.
Hope that better explains what & why I am trying to find out.
#25
I
ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
the service manual talks about a lift pump, but the parts diagram for your engine doesn't list it. Kohler is not forthcoming on the specs of their fuel pump, so I don't know what to tell you about the full output pressure. One thing about using the OEM pump though even though it may be more expensive is you know it is the correct pump with the correct outputs specs.
the service manual talks about a lift pump, but the parts diagram for your engine doesn't list it. Kohler is not forthcoming on the specs of their fuel pump, so I don't know what to tell you about the full output pressure. One thing about using the OEM pump though even though it may be more expensive is you know it is the correct pump with the correct outputs specs.
#26
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motoman
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motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
A random thought. Don't know about "lift" pumps, but my Pont, and Nissan have gas tank immersed pumps which pressurize the entire plumbing right to the injectors. Maybe IL ENG can explain why they use a lift pump on a relatively small system?
A random thought. Don't know about "lift" pumps, but my Pont, and Nissan have gas tank immersed pumps which pressurize the entire plumbing right to the injectors. Maybe IL ENG can explain why they use a lift pump on a relatively small system?
#27
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ILENGINE
I
ILENGINE
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
The first Kohler EFI engines had the pump mounted on or near the fuel tank. So maybe the charge pump was built into the injection pump. the newer Kohler ECH engines have the injection pump mounted on the engine and use a mechanical or electric pump to supply fuel to the injection pump since it isn't self priming.
The first Kohler EFI engines had the pump mounted on or near the fuel tank. So maybe the charge pump was built into the injection pump. the newer Kohler ECH engines have the injection pump mounted on the engine and use a mechanical or electric pump to supply fuel to the injection pump since it isn't self priming.
#28
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ajwgator
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ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Like you said ILEngine, the IPB for my engine doesn't show or list a charge pump. Both the Kohler & the Gravely IPB I have only show the injector pump. It is mounted on the frame/platform in front of the battery and is between & below the two tanks. The fuel lines in the tanks exit from the tanks almost at the top so they definitely do not gravity feed. The intake fuel line comes from the tank selector valve that is mount on the front panel under the seat. Each fuel tank has a supply & return fuel line that goes to the selector valve. No evidence of a charge pump anywhere that I can find. Wiring diagram for the mower doesn't show any either. When I turn the key to the on position the injector pump comes on, builds pressure to 41 psi and continues to run for another 10 seconds or so then turns off. Then it comes back on to repeat the cycle two more times. I can hear fuel running back into the fuel tank once the pressure get to 41 psi. The Kohler manual states this is the purge cycle that takes place when ever the key is turned on without starting the engine.
In my opinion the injector pump has to be powerful enough to suck the fuel from the bottom of the fuel tank, up to the top of the tank, on out through the selector valve, filter, and to the intake of the pump. As long as there is fuel in the tank and all the fuel lines have been purged of any air this task of sucking the fuel shouldn't be much of a problem. Simple physics so I really don't see a need for a charge pump as long as the injector fuel pump is supplying an excess of 39 psi +/- 3 psi. The excess is directed back into the fuel tanks from the fuel pressure regulator. I may have already said all this in a previous post and if so, sorry for repeating myself.
Still having a hard time considering an OEM replacement pump for $200.... but might just have to bite the bullet! The way it stands now I can always just mow for 30 minutes and take a little break...lol
The first Kohler EFI engines had the pump mounted on or near the fuel tank. So maybe the charge pump was built into the injection pump. the newer Kohler ECH engines have the injection pump mounted on the engine and use a mechanical or electric pump to supply fuel to the injection pump since it isn't self priming.
Like you said ILEngine, the IPB for my engine doesn't show or list a charge pump. Both the Kohler & the Gravely IPB I have only show the injector pump. It is mounted on the frame/platform in front of the battery and is between & below the two tanks. The fuel lines in the tanks exit from the tanks almost at the top so they definitely do not gravity feed. The intake fuel line comes from the tank selector valve that is mount on the front panel under the seat. Each fuel tank has a supply & return fuel line that goes to the selector valve. No evidence of a charge pump anywhere that I can find. Wiring diagram for the mower doesn't show any either. When I turn the key to the on position the injector pump comes on, builds pressure to 41 psi and continues to run for another 10 seconds or so then turns off. Then it comes back on to repeat the cycle two more times. I can hear fuel running back into the fuel tank once the pressure get to 41 psi. The Kohler manual states this is the purge cycle that takes place when ever the key is turned on without starting the engine.
In my opinion the injector pump has to be powerful enough to suck the fuel from the bottom of the fuel tank, up to the top of the tank, on out through the selector valve, filter, and to the intake of the pump. As long as there is fuel in the tank and all the fuel lines have been purged of any air this task of sucking the fuel shouldn't be much of a problem. Simple physics so I really don't see a need for a charge pump as long as the injector fuel pump is supplying an excess of 39 psi +/- 3 psi. The excess is directed back into the fuel tanks from the fuel pressure regulator. I may have already said all this in a previous post and if so, sorry for repeating myself.
Still having a hard time considering an OEM replacement pump for $200.... but might just have to bite the bullet! The way it stands now I can always just mow for 30 minutes and take a little break...lol
#29
P
pauly50
P
pauly50
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
hi , the lift pump is only lifting fuel from the tank, with no appreciable pressure and the output from the lift pump is filtered with a pleated paper filter 10 micron filter
and supplied to the pressure pump , the pressure pump supplies fuel to the metal can filter before the injectors ( injector filter screen can block up too) ( the filters inside the pressure pumps are 20 micron ) and can block up , pick up filters inside the tank are 75 micron i think the lift pump number is 808656 the number on the pump , these pump are vacuum and pressure pulse activated via the positive and negative crankcase pressures
is your system a in tank pump and regulator system or internal pick up and external pressure pump , with return line to tank and is the fuel pump mounted under the tank inside the chassis rail or on the rear cross rail behind the no2 cyl ? if it was me i would be putting kohler oem pump on , if using non oem pumps with higher output pressures can run into problems ie causing regulators to fail , possible overfueling , running rich
hope this info helps with your decsion
cheers pauly50
hi , the lift pump is only lifting fuel from the tank, with no appreciable pressure and the output from the lift pump is filtered with a pleated paper filter 10 micron filter
and supplied to the pressure pump , the pressure pump supplies fuel to the metal can filter before the injectors ( injector filter screen can block up too) ( the filters inside the pressure pumps are 20 micron ) and can block up , pick up filters inside the tank are 75 micron i think the lift pump number is 808656 the number on the pump , these pump are vacuum and pressure pulse activated via the positive and negative crankcase pressures
is your system a in tank pump and regulator system or internal pick up and external pressure pump , with return line to tank and is the fuel pump mounted under the tank inside the chassis rail or on the rear cross rail behind the no2 cyl ? if it was me i would be putting kohler oem pump on , if using non oem pumps with higher output pressures can run into problems ie causing regulators to fail , possible overfueling , running rich
hope this info helps with your decsion
cheers pauly50
#30
B
bertsmobile1
B
bertsmobile1
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
To limit the amount of high pressure fuel line to a minimum.
The mower will shake areound and bounce around a lot more than your car.
Common method for most deisel engines for donkeys years.
Have seen some equipment where the lift pump inside the fuel tank is not replaceable as it went into the tank before the tank was welded together.
Thus it is part of the tank assembly so will not show as a seperate item in a parts listing.
A random thought. Don't know about "lift" pumps, but my Pont, and Nissan have gas tank immersed pumps which pressurize the entire plumbing right to the injectors. Maybe IL ENG can explain why they use a lift pump on a relatively small system?
To limit the amount of high pressure fuel line to a minimum.
The mower will shake areound and bounce around a lot more than your car.
Common method for most deisel engines for donkeys years.
Have seen some equipment where the lift pump inside the fuel tank is not replaceable as it went into the tank before the tank was welded together.
Thus it is part of the tank assembly so will not show as a seperate item in a parts listing.
#31
M
motoman
M
motoman
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Bert, Pls explain "jump around," and "bounce around."
Bert, Pls explain "jump around," and "bounce around."
#32
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
Mine is internal pick up with an external pressure pump and has a return line to the tank. The external pressure pump is mounted on the chassis rail under the seat between the two fuel tanks. There is not any type of lift pump (vacuum/pressure pulse) mounted on the engine. I know what you are referring to because my non-EFI Kohler has one of these. I'm almost (99%) positive there is not any type of lift pump inside the fuel tank (and there would have to be two of them) because there isn't any wiring going into them.
The question of higher pump pressure pump vs the pressure produced by the OEM external pump and causing possible problems etc... the way I see it after studying it all with the help of everyone here... I came to this conclusion. The required fuel pressure is controlled completely by the fuel pressure regulator. The ECU assumes it will always be 39 psi +/- 3 no matter what. With the Bosch EFI system that I have, the ECU only controls two things: fuel pulse duration of the injectors, and the timing of firing from the ignition coils. It does these two things by using the data it receives from three sensors: the speed sensor, the throttle position sensor, and the oxygen sensor. Everything else is always assumed constant by the ECU. The fuel pressure regulator does not care what pressure is behind it because it dumps any excess over 39 psi +/- 3 back over into the fuel tanks. If the diaphragm in the regulator were to fail it is not going to over pressurize the injectors because the fuel would then exit out the atmospheric port on the regulator and just be a fuel leak.
So I went ahead an ordered an after market external pressure pump from Global Automotive, #GA2236 that have the following specs:GPH (FREE FLOW) is 30-40 and the item PSI (NOT REGULATED)= 70-95 psi and has a lifetime warranty, made in the USA, shipped to the door for $38.00. I think all will be just fine with it. I will follow up after all is installed to let everyone know how this worked out. Thanks again for everyone's input and help!
hi , the lift pump is only lifting fuel from the tank, with no appreciable pressure and the output from the lift pump is filtered with a pleated paper filter 10 micron filter
and supplied to the pressure pump , the pressure pump supplies fuel to the metal can filter before the injectors ( injector filter screen can block up too) ( the filters inside the pressure pumps are 20 micron ) and can block up , pick up filters inside the tank are 75 micron i think the lift pump number is 808656 the number on the pump , these pump are vacuum and pressure pulse activated via the positive and negative crankcase pressures
is your system a in tank pump and regulator system or internal pick up and external pressure pump , with return line to tank and is the fuel pump mounted under the tank inside the chassis rail or on the rear cross rail behind the no2 cyl ? if it was me i would be putting kohler oem pump on , if using non oem pumps with higher output pressures can run into problems ie causing regulators to fail , possible overfueling , running rich
hope this info helps with your decsion
cheers pauly50
Mine is internal pick up with an external pressure pump and has a return line to the tank. The external pressure pump is mounted on the chassis rail under the seat between the two fuel tanks. There is not any type of lift pump (vacuum/pressure pulse) mounted on the engine. I know what you are referring to because my non-EFI Kohler has one of these. I'm almost (99%) positive there is not any type of lift pump inside the fuel tank (and there would have to be two of them) because there isn't any wiring going into them.
The question of higher pump pressure pump vs the pressure produced by the OEM external pump and causing possible problems etc... the way I see it after studying it all with the help of everyone here... I came to this conclusion. The required fuel pressure is controlled completely by the fuel pressure regulator. The ECU assumes it will always be 39 psi +/- 3 no matter what. With the Bosch EFI system that I have, the ECU only controls two things: fuel pulse duration of the injectors, and the timing of firing from the ignition coils. It does these two things by using the data it receives from three sensors: the speed sensor, the throttle position sensor, and the oxygen sensor. Everything else is always assumed constant by the ECU. The fuel pressure regulator does not care what pressure is behind it because it dumps any excess over 39 psi +/- 3 back over into the fuel tanks. If the diaphragm in the regulator were to fail it is not going to over pressurize the injectors because the fuel would then exit out the atmospheric port on the regulator and just be a fuel leak.
So I went ahead an ordered an after market external pressure pump from Global Automotive, #GA2236 that have the following specs:GPH (FREE FLOW) is 30-40 and the item PSI (NOT REGULATED)= 70-95 psi and has a lifetime warranty, made in the USA, shipped to the door for $38.00. I think all will be just fine with it. I will follow up after all is installed to let everyone know how this worked out. Thanks again for everyone's input and help!
#33
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
This is my follow up after installing the new Global Automotive, #GA2236 electric fuel pump. The mower started up just fine and the pressure regulator maintained the system fuel pressure at 41 psi which is within the designed range of 39 psi +/- 3. The excess pressure output from the pump dumped back into the fuel tank as designed. This was just as it was before the pump replacement. The mower operated just fine under all loads and continued to do so for the one and half hours I ran it without an MIL light. So the fuel pump replacement is a definite fix for my original problem of only running for 30-45 minutes before registering a 34 & 31 code. Thanks again for everyone's input, ideas, and excellent help in this issue.
This is my follow up after installing the new Global Automotive, #GA2236 electric fuel pump. The mower started up just fine and the pressure regulator maintained the system fuel pressure at 41 psi which is within the designed range of 39 psi +/- 3. The excess pressure output from the pump dumped back into the fuel tank as designed. This was just as it was before the pump replacement. The mower operated just fine under all loads and continued to do so for the one and half hours I ran it without an MIL light. So the fuel pump replacement is a definite fix for my original problem of only running for 30-45 minutes before registering a 34 & 31 code. Thanks again for everyone's input, ideas, and excellent help in this issue.
#34
A
ajwgator
A
ajwgator
Re: Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minut
One more follow up... on a couple of points.
First; I just want to say that the Global Automotive #GA2236 electric fuel pump that I purchased was the exact match to the original equipment fuel pump that I removed from the mower in all aspects... in fact if laid side by side one couldn't tell any differences at all. Only thing missing were the OEM numbers that were stamped into the original.
Second; On the information concerning if lift pumps were needed or not... I had to take tank selector valve off today to repair the stem that you turn to select the left or right tank. In doing that I learned that the fuel pick lines from each tank siphon to the selector valve. I had to blow air back through the pick up lines to each tank to stop the flow coming from the tanks. That is the reason my system does not have any lift pumps to feed the electric fuel pump.
Glad to have my machine up and running well again!
This is my follow up after installing the new Global Automotive, #GA2236 electric fuel pump. The mower started up just fine and the pressure regulator maintained the system fuel pressure at 41 psi which is within the designed range of 39 psi +/- 3. The excess pressure output from the pump dumped back into the fuel tank as designed. This was just as it was before the pump replacement. The mower operated just fine under all loads and continued to do so for the one and half hours I ran it without an MIL light. So the fuel pump replacement is a definite fix for my original problem of only running for 30-45 minutes before registering a 34 & 31 code. Thanks again for everyone's input, ideas, and excellent help in this issue.
One more follow up... on a couple of points.
First; I just want to say that the Global Automotive #GA2236 electric fuel pump that I purchased was the exact match to the original equipment fuel pump that I removed from the mower in all aspects... in fact if laid side by side one couldn't tell any differences at all. Only thing missing were the OEM numbers that were stamped into the original.
Second; On the information concerning if lift pumps were needed or not... I had to take tank selector valve off today to repair the stem that you turn to select the left or right tank. In doing that I learned that the fuel pick lines from each tank siphon to the selector valve. I had to blow air back through the pick up lines to each tank to stop the flow coming from the tanks. That is the reason my system does not have any lift pumps to feed the electric fuel pump.
Glad to have my machine up and running well again!
#35
B
bmac08
B
bmac08
I have a Kohler 28hp Bosch EFI and having the exact same issue (code 31 after 30 mins, sputtering, etc). The fuel pump is tucked down pretty good on the frame below the regulator and electrical box, any tips on its removal and reinstallation?