F355 unsolvable issue - please help!

Discussion in '348/355' started by nicklondon, Jun 21, 2019.

  1. johnk...

    johnk... F1 Veteran

    Jun 11, 2004
    New England/FL
    Vibration/intermittent TC signal could be a cause. I watched the video in stop frame. The engine appear to be at 1000 rpm when the SDL flashes on. It then goes off and the RPM drops, then recovers back to 1000. The SDL flashes on/off again and the cycle repeats. It does seem possible that the injectors cut off momentarily and there is a slight time lag before the engine slows. Eventually the engine races to 3000 rpm and returns to normal idle. The 5-8 CEL is also on the entire time until the engine drops to normal idle after racing to 3k.

    After viewing frame by frame I'm more inclined to think intermittent TC or MAF problem.
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  3. 97 Spider

    97 Spider Formula 3
    Rossa Subscribed

    Dec 15, 2012
    Full Name:
    Exactly, I watched the video a decided not to even add my 2 cents.
    If you’re really looking for answers why would you mask the sound of what’s going on with music? Hearing the car is a major part of diagnosis. Heck the engine could be running smooth and the gauge cluster might have a short for all the video shows us. I know he explained what was going on but really... the music on the video made me click away. I also suggest if he wants help to shoot a new video. Longer, and let us hear the car. Maybe also record a bit at the engine bay while it’s happening.
    Beetle likes this.
  4. nicklondon

    nicklondon Rookie

    May 21, 2013
    Dear All,

    Thank you so much for all your comments - I'm overwhelmed with how how helpful all the information is. Just as an FYI, the car is not with me, she went to have a cam-belt service and they're trying to resolve the issue whilst it's there... I'm not that handy with a wrench!

    I've sent the thread to the engineer who has the car and I'm sure it will help him greatly. I'll keep you all updated on what the issue ended up being!

    P.S sorry about Phil Collins, it was the only video I have as the car isn't currently with me!
  5. Krisatcruz

    Krisatcruz Rookie

    Apr 15, 2017
    Hi was this issue resolved?
    ernie likes this.
  6. John Glen

    John Glen Formula Junior

    Dec 30, 2009
    Victoria, B.C, Can.
    Full Name:
    John Glen Wesanko
    I just completed a major engine out maintenance program on my 348 and upon re assembly I had an issue. The right side bank (1-4) was not firing. After much investigation I decided to look more closely at the engine harness that is fed through the firewall to the ECU. What I found was one of the wires going through the white nylon plug beside the main ecu plug was probably slightly misaligned and when I re connected this nylon plug it pushed one heavy green wire out the back of the plug (engine side) . Once I pushed the wire terminal properly back into the plug and joined together with the other half the connection was secure and running issues SOLVED ! Just a reminder that the engine harness can take a beating getting pulled through the firewall. Check the integrity of the plugs and pins...... JGW
    ernie, ShineKen and Qavion like this.
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  8. POLO35

    POLO35 Formula Junior

    Feb 21, 2005
    Treasure Coast Florida
    Full Name:
    I agree with one of the previous poster's ....sounds like its idle hunting. Try cleaning your throttle bodies it's very easy and can't hurt.
  9. POLO35

    POLO35 Formula Junior

    Feb 21, 2005
    Treasure Coast Florida
    Full Name:
    Are your cats and 02 sensors back on the car since putting the exhaust back to stock? Could be bad 02 or crossed wiring.
  10. 26street

    26street Karting

    Jan 30, 2021
    Westchester New York
    Full Name:
    Mark k
    Would like to know what your tech does as far as testing and results I’m sure armed with all the help here you will find it

    Sent from my iPhone using mobile app
  11. jssans

    jssans Formula Junior

    Jun 1, 2005
    St. Louis
    Full Name:
    I had similar issue. It was the connector to the MAF. Not a bad MAF. A tech who worked on Volvos figured out. Apparently F355’s use a Volvo MAF.

    Sent from my iPhone using Tapatalk
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