Kohler ECV740 No crank voltage

Discussion in 'Mechanic and Repair' started by Irritated Mechanic, Nov 9, 2018 at 4:53 PM.

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  1. Irritated Mechanic

    Irritated Mechanic LawnSite Member
    Messages: 6

    Been working on this for two days. I have to spark from the coils. After testing everything out it seemed like the ecu had a ground sticking. Put a new one and and had a misfire on cylinder two. Switched out coils and now it’s back to the same problem. Anybody have any ideas because I’m out of tricks.
     
  2. BigFish

    BigFish LawnSite Platinum Member
    Messages: 4,680

    The Kohler manual should be able to help, no? Ya gotta google it, or mayhaps another member will link ya up.
    Joisey Rick has a pretty good grip on them Kohler electronical gizmos ( along with other objects ). He should be chimin' in...
     
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  3. Walker56

    Walker56 LawnSite Silver Member
    Messages: 2,019

    I agree with BigFish. Ricky86 is the EFI guru. You could have a pin fitment or crank sensor signal issue. Do you have acess to a scope to see the signal coming from the crank sensor. From what I remember, that is what triggers the ECU to get the coils to work.
    Heres is the manual
    http://resources.kohler.com/power/kohler/enginesUS/pdf/24_690_02_EN.pdf
     
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  4. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,426

    My advice is listen to fish and walker.
    1) Get the manual
    2) Read it and get an understanding of the system. Don’t assume.
    Because I haven’t any idea what’s wrong.
    Either do you.
    I’m still mulling what a sticking ground is.
    Establish the fault. Critically important. Then worry about the fix.
    Follow the flow chart after reading. You must be methodical.
    And STOP throwing parts at it. You already wasted... what 175?????
    I rarely start any EFI repair without the manual open.
    And take any code with a grain. It tells you something’s wrong but rarely exactly what’s wrong.
     
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  5. Irritated Mechanic

    Irritated Mechanic LawnSite Member
    Messages: 6

    I’m used to automotive ecu’s that work on turning grounds on and off. I have the repair manual downloaded but I can’t find why I have two grounds going to the crank sensor. There’s two codes in it ( one for the injector on cylinder two and one for the O2) but I don’t have a code for the crank sensor or coils.
     
  6. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,426

    Ok. Yes works the same. coils injectors and fuel pump are hot all the time.
    What exactly is the problem.
    It cranks but no start?
    Or it starts with a misfire
     
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  7. Irritated Mechanic

    Irritated Mechanic LawnSite Member
    Messages: 6

    It was a crank no start. But after a new ecu I just had a misfire for cylinder two. Started to diagnose the misfire and it reverted back to the original problem of not having any spark with the same issue from the new ecu.
     
  8. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,426

    So after you move the harness around installing the ecu, you had a different symptom then a return to the original.
    Follow the flow chart and if you want to hear a possible correct/incorrect answer, it sounds like the harness. Perform a wiggle test. Wiggle the harness at different points to see if anything changes, while cranking engine. Your body parts are no match for rotating steel. Use you head performing test.
    It's one of the best tests to find an intermittent wiring problem.
    If it is, great I'm a genius. It it isn't, sorry charlie. Serves you right for listening to some unknown dipchit on a web site.. Good lord, you may have more knowledge than me.
    Listen, I have a lot of experience with theses engines. I learn something on every repair. Electrics never cooperate. Every repair is different. There's no quick answer.
    You have to follow a methodical process to find the problem. As I test, I write things down.
    The harness has reference numbers printed on the blue part of the connector, as you look into the cavity of the pins. They correspond to the wiring on the diagram. Use caution when probing.
    There no reason to touch the ecu. It wont tell you anything.
     
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  9. Walker56

    Walker56 LawnSite Silver Member
    Messages: 2,019

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  10. ricky86

    ricky86 LawnSite Silver Member
    Messages: 2,426

    .....and holding a probe on a pin that is so tiny looking for a problem is close to impossible. I was lucky enough to have old ecu’s and harnesses on hand. I took them apart and used the terminals, after soldering them, for use with testing. It’s time consuming work. Very very time comsuming. That why I write results down.
     
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