EFI 26 Kohler ground issue

Discussion in 'eXmark' started by Mowered, Jun 13, 2006.

  1. Mowered

    Mowered LawnSite Member
    from Canada
    Posts: 4

    I've been workin on solving my open loop, runnin rich problem.I searched extensively in back forums.I have a 2001 Efi 26 lazer z with 1600 hrs. I just recieved the oil temp sensor and ground kit today and ran for couple hours real strong then the rough runnin and smokin again. I have cleaned the grounds i have found, the main Ground from the battery, and one by the power regulator. How many are there? Will adding your own grounds help? I've put one from the starter to battery. I just want to eliminate the ground aspect of the problem altogether. I have the old style ecu with the metal case and the kit came with a bolt, nut and washer to be put in an empty hole in the ecu case but the bolt was too long and hit the frame so u couldn't't tighten it unless u took the ecu completely off. so i attached it to the mounting bolt of the ecu. I'm assuming this is fine? My muffler is new, but of course i suspect the oxygen sensor, i have at times had code 31 and 32. But it could be the oxygen sensor ground. What is the worst that people have seen by running in the open loop , cause it's tough to stop working when its not workin too bad under load.

    I'd appreciate any response , cause i love this site and have already learned more on here then from any other source. The exmark dealer here is useless as they are not a kohler dealer and can not even order parts. Is this common? And the kohler dealers have never seen these motors. I am in canada though and on an island , so that could be it.

  2. DEEJ

    DEEJ LawnSite Member
    Posts: 230


    I have that same exact machine, as well as a 2003 28 EFI. Both have the Ultracut decks - both are excellent trouble free machines that sip fuel. Highly recommended machines and engines.

    My problem with the 26 EFI a few years back was not grounding like I thought, but rather moisture and corrosion on the big connector to the ECU. There is a service bulletin out about this. The fix was to take the connector off, dry both halves of the connector thoroughly (I used light compressed air, then let it sit with a fan on it for a day), then coat both halves with proper dielectric grease, mate and unmate the connector a few times to spread the grease around and work the contacts a bit, then apply a bit more grease if required and put the connector on one last time. I believe the service bulletin also asks that you silicone the connection to keep further moisture out. I did not do this last step - but I have now been 2 years trouble free.

    In my experience it takes very little moisture at this connector to cause a problem. I still wash the machine periodically (blow them off most of the time), but take care not to direct water towards the ECU. The 28EFI doesn't seem to care!

  3. Keith

    Keith LawnSite Gold Member
    Posts: 3,977

    Even though I could never figure out which wire it was, when my new EPS started acting the same way in 2003, the final thing they did was the oil temp sensor and they found a bare wire somewhere. The first dealer didn't ****. The mower sat for over 2 weeks and the best they could do was crank it and let it run behind the fence. The second time the mower was in, they threw parts and troubleshooting instructions at it that were by the book. The next time, they finally got it. I will always believe it was the bare wire myself. In the world of computer controlled engines, sometimes the simplest things get overlooked.

    Everytime I am about willing to buy another EFI machine, I see another one of these threads pop up and remind me about the problems I had with mine. Gas savings are nice, but it's worthless if you have a problem like that.
  4. tomo

    tomo LawnSite Senior Member
    Posts: 660

    hello, offering my opinion on this issue on the small ehg workshops that typically attempt to fix engine management issues. Unfortunatly most shops even in my area do not have the experience that is required and usally built up over many years .I will follow with a few basic general ground rules and procedures i have learnt over the years.

    1/ machines only fail from 3 things, poor maintenance,the !!!!!!!! who worked on it, design.

    2/procedure check all basic operations of engine/ general health check, str mtr, altenator charge ,batt cond, all accesories functioning correctly, fully serviced, water in fuel tank.
    3/ compression wet/dry 4/leakdown test
    5/ power balance
    6/vacumn guage
    7/pressure test cooling system with plugs out
    8/exhaust in coolant test
    9/exhaust blockage
    10/fuel pressure
    11/fuel flow
    12/ fuelpress reg check
    13/injector duty cycle
    14/injector spray pattern and leak down test
    15/all general cable condition routing connection
    16/throtle body cleanliness and adjustment
    17/fault code check[point u in the direction but seldom give an accurate diagnosis of the cause and eg "take with a grain of salt". to many w/shops with out experience read to much into fault codes
    18/ check system voltages at indivdual pins on computer and compare to your knowledge or factory chart input curcuits or outputetc
    19a/use your sixth sense such as items going open curcuit when hot
    19/b more than two problems occuring at the same time 20/there are plenty of other checks, some maybe particular to an individual machine or injection type.
    21/ over the years i have found problems in all these areas
    Hope this helps tomo PS as u can see a small engine w/shop is up against it.Chain saws donot have eng management
  5. Mowered

    Mowered LawnSite Member
    from Canada
    Posts: 4

    Thanx guys for your responses. I cleaned and tightened the grounds again this morning, and with the new temp sensor and ground kit i ran strong all day today.
    I won't say it's fixed cause i've been proved wrong too many times b4 but it was sure great to have it working good. Especially with all the rain we've had, i'm behind 3 days as it is. I'll keep my fingers crossed.


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