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Kohler Command Pro 28 w/Bosch EFI Throwing 34 & 31 Code after runniig 30-45 minutes
- Thread starter ajwgator
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Export threadRe: 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!
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.
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!
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?