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Need help on 360 stumbling under light load intermittently.

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

  1. SoftwareDrone

    SoftwareDrone F1 Veteran
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    Jan 19, 2004
    6,493
    San Jose, California
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    Mike
    Look closely around the rim of the rivnut and make sure it's not black from arcing. If it were me, I would loosen the nut on the threaded stud, then see if I could move the rivnut by trying to wiggle the treaded stud.
    I was told there is another connection like this under one of the panels near the firewall (this time inside the cabin) that can do this. I don't know exactly where that one is at though.
     
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  3. DDavid

    DDavid Karting

    May 3, 2018
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    DDD
    Removed both wires, cleaned surfaces on firewall, wire connectors and bolt and reassembled. No arcing or looseness anywhere. I'd love to know more about the other connector inside the cabin though. Any advice will be greatly appreciated.
     
  4. 360+Volt=Prius

    360+Volt=Prius Formula 3
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    Sep 1, 2013
    1,416
    Western Mass
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    Raimondo
    How long have you had the car and When did the problem start?

    Is this something that occurred since you have owned it, or did you inherit this problem when you took ownership?



    Sent from my iPhone using FerrariChat
     
  5. SoftwareDrone

    SoftwareDrone F1 Veteran
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    Jan 19, 2004
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    I'll tell you who fixed my car and who knows about all those other ground points.

    Call Jesse at San Francisco Motorsports. 1-415-259-5488

    These guys are phenomenal. No one could help me with this problem (including the Ferrari dealers) but they fixed it. In fact, they rebuilt my 360 engine from the bare short block after I pushed out a head gasket, and it has been running perfectly for 30,000+ miles and has crazy horsepower. These guys are the real deal. They mostly work on late model Ferraris.
     
  6. 24000rpm

    24000rpm F1 Rookie

    how did u blow the head gasket? overheating?

     
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  8. zstyle

    zstyle Formula Junior
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    Jun 28, 2007
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    Some other areas to check:

    Oil within the plenum pooling up around the trumpets. This usually leads to oil being blown back onto MAFs. You've already replaced them but make sure there is no oil within plenum. Oil usually pools up when the oil sump is over filled.

    Ground strap between engine and chassis.
     
  9. Some Guy in the sky

    Sep 19, 2018
    183
    What did they do to get crazy horsepower?
     
  10. vrsurgeon

    vrsurgeon F1 World Champ
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    Dec 13, 2009
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    Other possibility is one or both of the throttle bodies aren't opening completely. On the side of the throttle body by the oval plastic is the motor, there is a gear that opens the valve body. This can wear and not open completely for a given throttle setting. Thus the stumble. perhaps on startup remove the MAF's with the key turned on, depress the throttle and see if both open equally and completely.
     
  11. one4torque

    one4torque F1 Rookie
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    May 20, 2018
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    I’ve had brand new mas be bad... try a known working pair from a buddy w a 360
     
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  13. SoftwareDrone

    SoftwareDrone F1 Veteran
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    Please PM me with my engine rebuild questions. I do not wish to hijack DDavid's thread and sincerely hope his issue has a resolution soon.
     
  14. DDavid

    DDavid Karting

    May 3, 2018
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    DDD
    Sorry for the late reply to all this, I've been away from my computer for a day or 2. I have added extra earth leads to various spots in and around the car. No oil in intake area at all and MAFs clean as new. As far as when problem eventuated, I feel the car has been a bit off since purchase. The single biggest improvement to the performance of the car was the fitting of the new MAFs. That gave the car an enormous kick in the arse. Was like it grew an extra few cylinders! However, it DIDN'T throw these codes before that, and now it does. So, the performance is far greater BUT now have this stumbling issue and codes all relating to either MAFs or o2 sensors. I'm interested in checking the throttle bodies....I'll have a look at that today hopefully.
     
  15. DDavid

    DDavid Karting

    May 3, 2018
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    DDD
    Checked the throttle bodies. All good. I gave it all a good clean inside the seat for the throttle blade/valve. Alas, the quest continues.
     
  16. brookliner7

    brookliner7 Formula Junior

    May 5, 2018
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    Hans
    How did you check the throttle bodies?
     
  17. DDavid

    DDavid Karting

    May 3, 2018
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    DDD
    Remove the rubber bellows off the throttle bodies that connect to the MAFs, get another person to sit in the car with the ignition on and operate the gas pedal to see if they look like they are completely in sync with one another.....they were.
     
  18. vrsurgeon

    vrsurgeon F1 World Champ
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    Darn! Was worth a shot...
     
  19. 360+Volt=Prius

    360+Volt=Prius Formula 3
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    Sep 1, 2013
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    Raimondo
    Sorry to quote my own post but 90% of diagnosis made by a good history.


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  20. KILOCHARLIE

    KILOCHARLIE Formula Junior

    Oct 14, 2012
    314
    Cardiff, UK
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    KC
    Any chance the MAF's could have been knock offs? There were fakes around a few years ago and even indy's were supplying them as they were hard to tell the difference.

    Sounds like a problem I've had on my car since purchase. Does it almost hold back when you floor the gas for a second before bucking up and taking off? Also when coming to a coaster stop does the idle fluctuate slightly like it's trying to find a smooth idle?
     
  21. DDavid

    DDavid Karting

    May 3, 2018
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    DDD
    That's pretty much exactly what it does. I'm intrigued by your post. I bought my MAFs from a UK supplier as they were hard to find in Australia. Any further information on getting original MAFs would be appreciated. They were Bosch ones, came in Bosch boxes etc.....but I know a LOT of stuff is make by knock off people.
     
  22. KILOCHARLIE

    KILOCHARLIE Formula Junior

    Oct 14, 2012
    314
    Cardiff, UK
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    KC
    Ok I definitely have the same issue then. I put up a thread a number of years ago with the same issue and had similar responses. I've checked as many of the earths on the car as I could find, I cleaned my MAF's but never replaced them and after much research accepted some 360's just are like it and learned to live with it. I never had any codes thrown due to it. I definitely remember conversations on her relating to imitation MAF's that had a thinner or thicker wire inside than genuine ones that people had issues with.

    Did you not have the problem with your original MAF's? From your post I'll buy some new ones and see if it has any effect on my problem and can let you know.
     
  23. LorenzoR

    LorenzoR Formula 3
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    Sep 26, 2015
    1,563
    Sarasota Fl
    Maybe i missed it but what was wrong with you old MAF,S.....If you still have them id put them back in and see what happens.
     
  24. KILOCHARLIE

    KILOCHARLIE Formula Junior

    Oct 14, 2012
    314
    Cardiff, UK
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    KC
    Google search fake Bosch MAF's and there's quite a lot of issues with them. Thet are very convincing. What exact place did you purchase them from?

    Ebay prices vary from £20 to £150 so there's definitely some disparity that is not normal. Eurospares sell for £130 each so I wouldn't expect resellers to get much below that. There are also advertisements aftermarket ones which I would assume perform better than fakes but no idea in comparison to Bosch ones.
     
  25. brookliner7

    brookliner7 Formula Junior

    May 5, 2018
    641
    San Antonio, TX
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    Hans
    Now you guys are making me paranoid my Bosch coils I got on eBay might be fake!

    Mine stumbles as well with light/moderate load. it's a euro 99, but also has the issue of sounding like a broken tractor/Harley Davidson for like 5 secs on a cold start then it sorts itself out and idles normal...not sure how this helps me track down my issue but assume ot must be related.... I don't have any codes.

    never had my injectors cleaned so I might start there.
     

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