kohler command pro 26 Efi fault code 34

mjhull

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Nov 3, 2012
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Hellp my kohler 26 efi is having a fault code 34 which is fuel system/oxygen sensor, I don't think its the oxygen sensor because it was replaced two years ago. I had just replaced the crank case seal so the engine was ripped out and wile it was out I had replaced the fuel filter. I put it all back together and now its throwing a code 34, and after it throws the code it runs terrible with a miss, and also looks like it runs very lean on fuel. (Sparkplugs are black) if the computer is reset the mower runs great, until after 15 minutes of running it throws that code again. Any ideas on what it could be, I'm guessing it has something to do with electrical. Thank you, any thoughts will be great!
 

Ifixdit

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Hellp my kohler 26 efi is having a fault code 34 which is fuel system/oxygen sensor, I don't think its the oxygen sensor because it was replaced two years ago. I had just replaced the crank case seal so the engine was ripped out and wile it was out I had replaced the fuel filter. I put it all back together and now its throwing a code 34, and after it throws the code it runs terrible with a miss, and also looks like it runs very lean on fuel. (Sparkplugs are black) if the computer is reset the mower runs great, until after 15 minutes of running it throws that code again. Any ideas on what it could be, I'm guessing it has something to do with electrical. Thank you, any thoughts will be great!

Google Kohler 26 EFI fault code 34 and go to the service bulletin posted under Mymowerparts.com. Page 8 has a fix related to the wiring harness ground terminal. For whatever reason I couldn't cut and paste it here. Hope that helps!!
 

motoman

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From the language used to describe the problem you are somewhat into car EFI (throwing a code). If Kohler builds 'em don't they sell factoy workshop manuals? As you may know car manuals are often good if you will follow their trouble shooting charts. Often this can be done with a meter (vom) looking for votages and grounds. H-Frt sells meters cheap. Go for the middle priced ones.

Edit. Running lean on fuel is not black. It is light tan to white.
 
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