28 hp Kohler EFI need help.

Discussion in 'Mechanic and Repair' started by bart may, May 24, 2008.

  1. bart may

    bart may LawnSite Senior Member
    from montana
    Posts: 273

    The engine only has around 500 hrs and it just started running rough. Almost felt like it was missing and choking out. I know it has no carb so there's no choke to adjust. I pulled the plugs and one side has powdery black residue and the other was burning white!! It seems one side is real rich and the other real lean. I changed plugs and ran it some more and it seems to stay the same with the mentioned plug colors. I also changed the air filter just in case. It did run a little better after the plug change but I'm still getting that powdery black on one and not on the other. Any advice on what might be going on? Can a bad O2 sensor cause these symptoms? Thanks for your help.
     
  2. jkilov

    jkilov LawnSite Bronze Member
    from MS
    Posts: 1,415

    Sure sounds like it.Does it have a single pump, dual injectors?
    If one injector is clogged with dirt the other will spray more fuel than needed.
     
  3. bart may

    bart may LawnSite Senior Member
    from montana
    Posts: 273

    I'm not sure it it has dual injectors or a single. I have a friend who is a mechanic and can work on stuff for me. Are the injectors a tough one too clean?
     
  4. jkilov

    jkilov LawnSite Bronze Member
    from MS
    Posts: 1,415

    I just checked and it has two injectors.

    I suggest you try to add one of those fuel additives. They contain some sort of cleaning agent that might just work.

    If it does'nt improve after a couple of tanks of fuel ask your mechanic to tear it down. Since he works on cars doing this should be a breeze.

    Here's just a schematic view, he'll know what to do.

    cvtwinefi.JPG
     
  5. bart may

    bart may LawnSite Senior Member
    from montana
    Posts: 273

    Thanks for the help jkilov. I'm going to try an injector cleaner as mentioned then go from there. Thanks again for your help. Bart
     
  6. totallawncare25

    totallawncare25 LawnSite Senior Member
    from TN
    Posts: 288

    yeah sounds like a dirty injector you might want to change the fuel filter also as it might have some more trash in it also.. could also be a bad ignition coil not fireing correctly too ??? I have the same engine it only has 7 hours on it on a new exmark efi... what is your engine on ???
     
  7. sawman65

    sawman65 LawnSite Senior Member
    Posts: 751

    if its on a exmark check all the grounds they have been a problem on the walkers also. allways look to the simple stuff first. also those injectors are touchey and will leak badly when messed with to much. it sounds like its running an open loop. this most times happends from a bad ground some where in the loop or system. if you do change the filter be sure to use the correct clamps or it will leak. and catch fire. these units are not for the shade tree mechanic. with out a laptop the plug and the program you will be lost trying to trouble shoot them.
     
  8. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Posts: 450

    Cycle your key on 3 times and then count the amount of blinks you get on the red light on your dash. Six blinks, pause, then one more and it stays on solid meens the fuel injection system is working OK. You may have a blown intake gasket or head gasket also, as the lean cylinder is actually overheating because it's doing all the work. We need more info to help you out more. Disconnect the wire at your O2 sensor, and pullit out of your muffler. if it's pitch black, blow it off, and use some gold anti-seize lightly ON THREADS ONLY when screwing back in. If on an Exmark, some used metal computer boxes that use to get water in them and mess with the computer. These systems are very electric sensetive. Make sure battery is up to snuff. Also, coils are external, make sure you have good blue chrisp spark on both cylinders, although I don't think I ever remember replacing an EGI coil. Make sure all your grounds are clean. A little corrosion will mess with these systems. I meen we are talking miliamps!!!
     
  9. Sharpcut 1

    Sharpcut 1 LawnSite Senior Member
    Posts: 450

    P.S. Fuel filters are special on these units as they run on 39 psi. You will blow a regular fuel filter out and possibly start a fire if you start messing with the fuel system. Good luck
     
  10. sawman65

    sawman65 LawnSite Senior Member
    Posts: 751

    with a bad ground it will still give the all good code.
     

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