Walker Mower 26 hp EFI MT GHS - blown ecu?

Discussion in 'Mechanic and Repair' started by MowinginEureka, Sep 10, 2009.

  1. MowinginEureka

    MowinginEureka LawnSite Member
    Posts: 238

    Ok, so my mower is a 2000 model 26 hp EFI 42" MT GHS that has 329 hours on it total and a hi dump kit. For the last few months it has had a sporadic check engine light and finally started to exhibit some symptoms recently. It tries to die randomly while mowing, has difficulty throttling up in all conditions whether just started or while being used. But these problems are sporadic, it will go hours without a problem, but the check engine light will still come on from time to time. I tried to take it in but the shop says that the ecu will not interface with their computer. Its my ECU, but theres no way to know what the problem is otherwise unless the guy tries to troubleshoot it for hours and hours starting with the throttle positioning sensor, 02 sensor, and other sensors. It does have a code 42, but the sensor that code talks about (dont remember) the tech tested with a meter and it was well within parameters. So somethings awry somewhere. They quote me a new ECU for 519.00, I cant find one on any website including ebay. Kohlers part number on it is a 24 584 22-S. Its a Kohler Command unit with a metal case, not plastic. If anyone knows where one is cheaper, new or used, or possibly what the problem might be. Let me know. I have put 1000 dollars in this mower since I got it a year ago. I have only put on 50 hours and it only has 329 hours on it total.
     
  2. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    The problem you're describing doesn't sound like a ECU issue. With a code 42 there is a problem with the oil temp sensor or the wiring to it. If the sensor checks good then I would have to look at the plug connector. There was at one time an issue with those and there is a repair kit for that. The part number for the kit is 24 755 134-S and the suggested price is $35.03. You are going to need to fix that first before you can diagnose any other problems. The kit comes with a new sensor and a new wiring pigtail. There were some issues with getting moisture and corrosion in the connector. I would start there. It's a pretty simple repair.
     
  3. pugs

    pugs LawnSite Gold Member
    Posts: 3,018

    Sounds like the shop doesnt have the kohler test equipment for EFI engines...

    If you do end up needing an ECU its probably a kit that converts it to a newer plastic box unit...thats why its so expensive I would think.
     
  4. MowinginEureka

    MowinginEureka LawnSite Member
    Posts: 238

    Ok. I will talk to the shop about the plug connector and make sure they checked it. Heres the problem though, the shop DOES have the software and all to check EFI Kohler engines. Mine is messed up somehow, they believe it is related. The Plastic box conversion kit is separate from the actual ECU. Hey Steam, you sound like you know what you are talking about. Are you a shop tech or something?
     
  5. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    There isn't much of a check for the plug connector but if you have a code 42 and the sensor is good there really isn't anything else it could be. The new connector has a boot on it that seals out moisture. You are dealing with very low voltages here and it doesn't take much corrosion to disrupt those voltages and cause problems. If the computers doesn't get the proper voltage from the sensor then it will give you performance problems. If you are getting a code 42 the computer isn't getting the proper voltage signal from the oil temp sensor. Install the kit and go from there. You could have other problems but if you are only getting the code 42 then I would stick with the temp sensor and the kit. Also you don't really have to have the computer program to troubleshoot this engine but it helps. The self diagnose system this engine has many times is all you need.

    Eureka, I am not actually the wrench turner but provide tech support to those who do and I pretty much only deal with Kohler engines. I also have a side business of selling parts for lawn and garden equipment and engines.

    As far as your metal cased computer goes it is discontinued, which it sounds like you already know. I don't think you need a computer but if you do the best you can probably hope for if you don't want to buy the conversion kit is find a used unit from someone who maybe has a failed engine. Exmark used the same computer on their early units so finding a used one isn't impossible.
     
  6. MowinginEureka

    MowinginEureka LawnSite Member
    Posts: 238

    Hey Veg. My stupid dealer says they have called up Kohler and all their west coast suppliers, but cannot find the stupid conversion kit for my metal ecu. They say mine is a 32 pin and the new ones are 26 pin and have a different wiring harness. They say Kohler says the number doesnt exist that I gave them for it or acknowledge that there even is a conversion kit...which I got off of the Kohler wesbite. I even downloaded the PDF file for how to install it..off of the Kohler site. What gives? Do you happen to know if it DOES exist, and if so, where to get this conversion kit, does it include an ECU, does it require a separate harness, and how much? Kohler has crappy customer service, its been 3 full business days, and I still have no decent answer from Kohler/my dealer on a price or an actual solution despite the dealer putting in 4 phone calls! I did however order the plug connector to my mechanics dismay. He seems adamant on me ordering that ECU, so does Kohler apparently he says. Im thinking of selling the stupid mower if the plug fixes the problem. All I have had with this mower is problems. Maybe buy a 25 hp carbureted or maybe a diesel model. I dont know what to do at this point...pain in my butt.
     
  7. VegetiveSteam

    VegetiveSteam LawnSite Senior Member
    Posts: 297

    Eureka,

    The conversion kit part number you would need to replace your 24 584 22-S is 24 755 169-S. Right now Kohler has no stock but they should be available actually in the next few days. This kit includes a new wiring harness so the pin count doesn't matter. Whoever you've been talking with evidently hasn't actually talked with anyone at Kohler because anyone at Kohler would know about the coversion kit. I'll be selling the kit for 620.00 but at this point I really don't think you need a computer. Again, with a code 42 the first thing I would do is install the 24 755 134-S kit. It's only a 35.00 kit and can be installed in half an hour or less.
     
  8. pugs

    pugs LawnSite Gold Member
    Posts: 3,018

    Yah you can diagnose them without the laptop hookup. Just seems odd that if they have the wires to hookup to newer ones....well nothing has changed as far as the hookup goes that I am aware of. So that seemed kinda strange that they can hookup to the new ones but not the old ones.

    Sounds like VegetiveSteam has dealt with alot of these...I would listen to his suggestion.

    There really is nothing wrong with these engines. But if you have a dealer that is not willing to learn about them, you will have problems.

    I used to see the 31HP liquid cooled ones. Built a wiring harness/fuel tank setup to run them on our test stand.

    Dont see the EFI's as much anymore...wish I did as they are actually fairly simple to work on.
     
  9. MowinginEureka

    MowinginEureka LawnSite Member
    Posts: 238

    Yeah, so dealer still hasnt called me back. Big surprise. They said they could try to diagnose the issue but said it would be as much in labor for him to track down the issue as it would be for a brand new ECU, which if there was an ecu that would give him an exact code or whatever, that would solve two issues. Fix the ecu and find out whats wrong with the mower...Kinda makes sense. Except for the fact that Veg's logic on the plug connector sounds like a no brainer to try first. But if all else fails and that is the problem. Im still left with an ECU thats broken that will not spit out diagnostic stuff...wont that cause issues for me later anyhow? I will be having the plug connector installed first no matter what. Thanks.
     
  10. MowinginEureka

    MowinginEureka LawnSite Member
    Posts: 238

    Yeah, so dealer still hasnt called me back. Big surprise. They said they could try to diagnose the issue but said it would be as much in labor for him to track down the issue as it would be for a brand new ECU, which if there was an ecu that would give him an exact code or whatever, that would solve two issues. Fix the ecu and find out whats wrong with the mower...Kinda makes sense. Except for the fact that Veg's logic on the plug connector sounds like a no brainer to try first. But if all else fails and that is the problem. Im still left with an ECU thats broken that will not spit out diagnostic stuff...wont that cause issues for me later anyhow? I will be having the plug connector installed first no matter what. Thanks.
     

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