Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minutes

[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.

 

[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.

 

[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.

 

[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]

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

 

[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.

 

[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.

 

[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!

 

[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

 

[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.