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Kohler CV26 EFI missing running rich

Discussion in 'Mechanic and Repair' started by crater, Aug 26, 2012.

  1. crater

    crater LawnSite Member
    Messages: 36

    I have a Kohler CV26 EFI on a country clipper. Fault code is 34 and 31. Lately it has been missing and bogging down when under load. Misses at idle and full. I replace the plugs, still does it. I have service man for it so I started testing. O2 sensor seems to test ok. As far as I could test the TPS it tested ok until I opened it up to full throtle, my meter went to 0 supposed to be 1800-3000 ohms but I'm not convinced it's the TPS cause it misses at idle also. Any ideas out there as what this could be. As I said there are more tests for the TPS, BUT I'm not sure how to perform them with the TPS mounted as there is no room for probes. Continunity tested ok on the O2 sensor also.

  2. crater

    crater LawnSite Member
    Messages: 36

    So what do you guys think? Fuel or electrical related. I'm leaning toward electrical.
    If the TPS was shorting out would it make the motor mis-fire at idle and run rich when under a load?
    BTY I called my dealer yesterday and there mechanic (great guy to work with, very knowledgable) quit. So it looks like I'm going to be on my own on this.
  3. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029


    It would be easy to determine which is causing the issue with a simple in-line spark tester, There are many styles and this is one of four styles I use;


    From your description I'd lean toward ignition as well, If it is "skipping" it will run rich from not being able to burn the fuel in the "skipping" cylinder.

    Check with your local dealers and see if they have a spark tester, We keep them in stock.....
  4. crater

    crater LawnSite Member
    Messages: 36

    I have tested with a spark tester, not a in-line as your picture shows but one that just tests the wire, it mimics a plug, I set the gap and watch for spark. It seems to have a consistant spark, but thats just by the seat of my pants, it's far from a scope. I've talked to a couple of dealer mechanics (at different dealers) and say they really haven't had problems with this motor so at least they admitted they be in the dark also except one of them has the PC based software to diagnose the EFI system. And again I'm not convinced that it is fuel related. Just curious if anyone has had a short in the wiring harness that has cause a mis-fire but not a consistant mis-fire.
    Yea, I get that due to the mis-fire the motor will run rich, and even probally worse due to the ECU via the O2 sensor thinking it needs more fuel cause something is'nt running right or something along that line. Anyway any ideas?
  5. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    If you suspect ignition, it needs to be tested while running and sometimes under load. ignition modules can act different ways and heat can make a difference, Get a in-line tester or test the coils per the service manual or take it to the dealer with the diagnostic program, the program will also check the ignition system.......
  6. crater

    crater LawnSite Member
    Messages: 36

    :dizzy:and the trouble goes on.:confused:
    I have tested the coils (resistance test) good
    o2 sensor (resistance) good
    TPS --Good
    I took the flywheel off thinking maybe the keyway was worn, I found that all but 1 magnet had come unglued from flywheel and where all stuck to the stator, I glued them back to flywheel re-assembled engine, started motor waited about 3 min and it starts to bog down and revs back up (not high) then under load it mis-fires. But at idle it will bog down the recover, misfire, bog down ect. I thought that it was probally the O2 sensor due to it warming up and going open loop with a faulty o2 sensor. I installed a new sensor but again around 2-3 min it runs then starts the, coughing, sputtering cycle again. The coils are not hot to the touch anyway and they tested good soooo I'm really out of ideas now.
    Really need some help on this one. ANYONE with an idea??
  7. piston slapper

    piston slapper LawnSite Platinum Member
    Messages: 4,335

    Did you get the flywheel magnets back in the right order.?
    There are 2 different magnets...the poles are north-south-north and south-north-south.
    If you get them in the wrong order they will cancel themselves out...no charging.
    Did you gap the flywheel sensor gapped at .060 .?
    Any new codes showing up ?
    Posted via Mobile Device
  8. crater

    crater LawnSite Member
    Messages: 36

    Hmm, don't know about the magnets order. Now, how could I tell? and I didn't take the engine speed sensor off and it wasn't loose, so although it may have rattled out of position I don't suspect it. On the magnet order, could I somewhere, like the reguator, test the voltage to see if I was getting any voltage back out? I am not above trearing it back down to check anything I can, besides check the engine speed sensor should be easy once the top cover is off. Which isn't too time consuming anyway.
    Thanks Piston Slapper for joining in, I sorely need some advice on this.
  9. crater

    crater LawnSite Member
    Messages: 36

    Code 34 is the only code. Cleared codes after new o2 sensor install, ran until it started acting up then checked code again. Code 34, MIL is constantly lite up while running.
  10. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029


    Do you really trust your "glue" job ?

    I've seen magnets come loose and punch holes in the top of engine blocks.....

    The first thing mentioned in the EFI manual section is to check the condition of the engine first, A cylinder leak-down test gives a good idea what's going on inside.

    The MIL light gives a idea which way to go for troubleshooting, If there's no MIL or it's non-functional the manual flow charts and test procedures are the only way to go if you don't have the software program.

    I'd suggest starting from the top and following each step as outlined, If you get to the end of the test procedures and all components pass, Look closer at the ECU.....

    I've used the flow charts a couple times to locate issues with success, But it does take a little time....

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