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Need help on 360 stumbling under light load intermittently.

Discussion in '360/430' started by DDavid, Sep 9, 2019.

  1. DDavid

    DDavid Rookie
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    May 3, 2018
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    DDD
    My 2000 360 manual Spider has a fairly constant fault that is driving me crazy. I've tried to solve this doing the usual work.....replaced many parts along the way, and yet still it happens.
    It's hard to pin down when the stumbling happens, mostly under light load at cruise. Having said that it can also do it under hard acceleration too.
    Parts replaced thus far - fuel pumps, MAF sensors, all four 02 sensors, all coils and plugs, fuel injectors removed and professionally cleaned and flow tested (all OK) and lastly crank angle sensors. The car has done 63,000 kilometres (Australian guy here!) and aside from this fault.....the car's perfect.
    I regularly get trouble codes P0102 and P0152. I've swapped MAF sensors from left to right, same with upstream 02 sensors and as far as drivability goes, it's made no difference. Having said that, it hasn't thrown any codes (YET) but I'm braced for the inevitable blow. The stumbling feels kind of like a momentary misfire, but it isn't. My gut feeling is perhaps an electrical glitch somewhere, a plug to a sensor that is weird (oxidised) and making resistance? I'd be most appreciative of any advice. I'm a retired mechanic and know my way around most car related things.....although this car is definitely the one that is forcing me to navigate uncharted waters.
     
  2. 24000rpm

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    not sure what's happening. So you replace all o2 sensors and MAFs, and you still got p0102/0152 or the code never appears after the replacement?
     
  3. DDavid

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    It still appears despite changing many components including 02 sensors and Mafs.
     
  4. 24000rpm

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    wow , if new maf and new o2 sensor still get you P0102 and P0152, then im be scratching my heads too

    but if no code appears just the stumbling, i'd check vacuum leak.

     
  5. 24000rpm

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    on a second thought, check wiring of maf and o2

    a
     
  6. DDavid

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    When you say check wiring of MAF and o2, I've actually replaced the plugs on the wiring loom that go onto the MAFs, and have ordered new plugs for the o2 sensors as well. I agree that more than likely it's a wiring issue. Any further advice regarding what and how to check wiring would be GREATLY appreciated.
     
  7. 24000rpm

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    sorry, I should be more specific. Actually i am chasing a different problem of my 360 which entails checking wiring too

    so, to be more specific, check wiring means check the "harness side" of the wiring. for exapmle, i'd check the harness that connect to the o2 sensor ( 2 connectors makes 1 connection. because your o2 sensor is new, so u need to check the connector and its wiring on the other side. since you replaced the plugs, that leaves the real wires.)

     
  8. RedNeck

    RedNeck F1 Rookie
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    Have you smoke tested the vacuum system? Does sound like it could be vacuum related. The intake runner gaskets are a very common failure item on these cars.
     
    RANDY6005 and brookliner7 like this.
  9. mello

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    Check your ground points. There are lots of them.
     
  10. DDavid

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    I also thought of that. I've gone through all the ground wires I could find and removed them, cleaned all surfaces where they goto and from and refitted. I've also run several other grounds of my own making. As I said, I'm convinced its a wiring fault, and as I tried to explain, I've already replaced the wiring plugs FROM the loom to the MAFs, so all that checks out....however where the OTHER side of the MAF wiring goes....as in to the ECU, well I have no idea about what to do on that end.
     
  11. DDavid

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    Oh....and I actually have smoke tested the intake side of the car and the ONLY leak detected was a VERY small one underneath the red covers where the actuator is for the intake manifold valve system. However it was so small that I decided the amount of work to repair it wasn't justified. I absolutely don't believe that is the cause of the stumbling or the throwing of codes. Intake gaskets are good too. I'm completely convinced it's some gremlins in the wiring/electrical system. Someone else must be suffering with similar problems. Perhaps we can all help each other.
     
  12. mello

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    There is ground wire close to each ECU. You might want to check those ground point. While you're at it, re-seat and do a visual inspection on the ECU connector.
     
  13. SoftwareDrone

    SoftwareDrone F1 Veteran
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    I had this exact same problem - for THREE YEARS. I tried EVERYTHING. Everything mentioned in this thread. It would just stumble every so often, no codes. Like once every two weeks or so.
    My mechanic told me that another guy with a 360 called him and said he had the same problem, but it was happening all the time. They figured out what was wrong with his car, fixed it, picked my car up and checked, and the same thing was wrong with my car. They fixed it (two dollar fix) and it never happened again.

    Here's what it was:

    On the firewall in the front, behind the cover that surrounds the master battery cutoff switch, is a rivnut. The rivnut is pressed into the firewall, and a threaded stud is screwed into the rivnut. The traction control ground wire has a ring terminal on the end, that goes over the threaded stud and is bolted down. Well what happens is that the rivnut itself comes loose from the firewall, and whenever you gun it (or even go over a bump just a certain way), it shorts out and cuts the throttle for a second. They replaced the rivnut, and, voila! Problem solved.
     
  14. DDavid

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    Can you please have a look at the photos I've posted and tell me roughly where it might be? For the life of me I can't find it so far......
    Image Unavailable, Please Login Image Unavailable, Please Login
     
  15. 24000rpm

    24000rpm F1 Rookie
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    u got me thinking. If you use the "asr off" mode, then your symptom(not problem), will go away. Logical?


     
  16. 24000rpm

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    im looking for it for you now. hold on

     
  17. DDavid

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    I very much appreciate your help.
     
  18. 24000rpm

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  19. 24000rpm

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  20. 24000rpm

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    If that's culprit, you probably need to remove wheel, wheel mudguard.

    but still, is your stumble associated with your MAF and O2 code? or they are isolated incidents?
     
  21. 24000rpm

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    or maybe "on" the wall, or on the "side wall"
    check it out, trace the wire from your abs unit.

     
  22. DDavid

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    I found it. Annoyingly it's still tight and feels good......damn it!!
     
  23. 24000rpm

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    remove it, wd40 it, clean it, screw it up.

     
  24. DDavid

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    I drove it last night and this time it threw out a P1104 as well. Everything seems to be related to either MAF or o2 sensors.....but they're all new. Driving me nuts.....!!!
     
  25. DDavid

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    I was thinking of doing just that....now I definitely will. Going out to do it now.
     

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