26hp efi walker running rough??

Discussion in 'Mechanic and Repair' started by jcan, Oct 3, 2013.

  1. jcan

    jcan LawnSite Member
    Posts: 40

    What did yours do when you turned the blades on? Was the service light coming on?
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  2. ZX12R

    ZX12R LawnSite Senior Member
    Posts: 775

    Mine spit and sputted so bad,I did not even try to engage blades. My bulb was burnt out,so I never saw the light.
     
  3. jcan

    jcan LawnSite Member
    Posts: 40

    Ok I fount an o2 sensor at the auto parts store and it saves me a lot of money other than buying a factory one, wish the fuel pump was the same story cause I priced one of those and it was like 215! Crazy right
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  4. ZX12R

    ZX12R LawnSite Senior Member
    Posts: 775

  5. jcan

    jcan LawnSite Member
    Posts: 40

    Ok guys I put new plugs in today and new o2 sensor, and when I crank it up it just runs at a low idle??? Won't speed up when I turn up the throttle or do anything. Any input?? I guess be putting the old sensor in tomorrow as it ran better with the old one in
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  6. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Posts: 718

    Not very surprising being that you are just throwing parts at it to begin with and secondly using non oem parts at that...

    As mentioned a page or two ago, what is the fuel pressure reading? That is where to start with EFI problems! No a bad fuel pump or restricted fuel filter will NOT throw any codes...

    As far as yours thowing a Code 34, well here are the possibilities...

    Another thing to know is which version ECU is on your unit...
     

    Attached Files:

  7. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Posts: 718

    Or some more good reading...

    EFI Troubleshooting...
     

    Attached Files:

  8. jcan

    jcan LawnSite Member
    Posts: 40

    Thanks Jeff ^ lots of good info in those links you attached, I looked at them closely and most of my problems/symptoms seem to be possibly leading back to tps problems. I took it to my nearest dealer and let them see the what was going on and they assured me it was tps problems especially on how old my mower is and amount of hours. They priced me out a whole new tps setup with intake and manifold for $320. Has anyone had this similar problem? I would like to check the fuel pressure but how might I go about that? I've never done it so I wouldn't know
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  9. Jeff in AL

    Jeff in AL LawnSite Senior Member
    from Alabama
    Posts: 718

    I have seen a few issues... Most were on high hour units that had a worn throttle shaft which sends incorrect signals from the TPS to the ECU.

    Does the dealer you took your unit to have the Diagnostic Software? If so, once the ECU is linked up to the software, it should be pretty clear where the problem lies.

    On the fuel rail there is a schrader valve in front of the manifold/TPS. That is where a fuel pressure gauge connects to read fuel pressure... Min of 39 PSI!

    I had a Walker mower that I was pulling my hair out on as I could not duplicate the customers complaint... Which was that the unit would run for a "while" and then loose power and die. I checked the codes and cleared them. Reran the unit, and it ran fine! Called the customer and he picked it up to use. Brought it back in a few hours with the same problem. I checked codes again, none since my reset! I checked fuel pressure again and it was fine. I called the customer and talked about the exact details of the issue... Long story shorter, he came back and drove the unit around with my pressure gauge hanging on the side if the unit for approx. 45 minutes... Then the unit started to loose power and spit! I checked fuel pressure and it was bouncing between 20-about 28 PSI then back up to 39 PSI! When it was reading the 39 PSI it would run fine, but act up when the pressure dropped!
    It ended up being fine sediment in the fuel tank that would slowly restrict the fuel pickup screen in the tank... When the unit was shut off or died, the fuel system lost the vacuum and drained back into the tank and "self cleaned" the screen... Until the unit was started, used and became restricted again!
    I was glad to finally find that problem and get it resolved... Still running today, no problems... Or codes...:)
     
  10. ZX12R

    ZX12R LawnSite Senior Member
    Posts: 775


    What if they install that and the problem still persists? It baffles me ,that with the hours u have,they did not mention the original fuel pump. Will they atleast check fuel pressure? Did u check your in-tank fuel line? It could be other things as well like injectors. If it were my machine,I would change the fuel pump myself due to your hours,and if it still ran bad,find a dealer with the software. As Jeff mentioned,that will point u right to the problem.

    The EFI units on earlier models like ours are the equivalents of the closed loop systems first used on cars in the early 1980's........pretty simple ......just need to find a dealer with software who took the classes and the time to understand it.

    Do a google search on Kohler efi service bulletins 267,268,and 269. Good info there that may pertain to your model.
     

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