Stalling out then backfiring but engine doesn't stop? | FerrariChat
Buy

Stalling out then backfiring but engine doesn't stop?

Discussion in '308/328' started by Speedsterbeast, Jun 13, 2020.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. Speedsterbeast

    Speedsterbeast Rookie

    Nov 20, 2018
    31
    Thunder Bay Ontario
    Full Name:
    Cory Zyromsky
    #1 Speedsterbeast, Jun 13, 2020
    1982 GTSi
    Looking for suggestions on what I'm guessing is a fuel problem.
    It is intermittent, but increasing in occurance.
    While driving, the tachometer drops to 0 while the engine is still running, but hesitates and doesn't pull.
    Then after 3-8 seconds the tach jumps up to the accurate reading and the car backfires and then is fine.
    Happens at anytime- idle / speed/ coasting / acceleration
    I'm doubting it's bad fuel. I thought maybe the fuel cap was the issue because when I remove it I get a lot of suction (not venting properly?), but I left it loose after fueling up today and the problem happened more than normal.
    I used to race VW Scirrocos and they had the BOSCH FI system. I've had bad injectors before and it sounds similar, so that is what I'm going to look at first- unless there are some other suggestions- Anyone?
     
  2. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    11,190
    CT
    Full Name:
    John Kreskovsky
    #2 johnk..., Jun 13, 2020
    Sounds like you are loosing the 1-4 bank. Electrical problem with the 1-4 digiplex. Bad connection.
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,630
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    #3 Steve Magnusson, Jun 13, 2020
    Most likely you are losing a bank of ignition (so the engine stays running on the "good" bank, but at 1/2 power -- then when it wakes back up = the fuel in the exhaust system ignites = backfire). Determine which bank is losing spark, then swap the connectors on the Digiplex ignition ECUs:
    If the lost spark moves to the other bank = not a good sign for one of the Digiplex ECUs
    If the lost spark stays on the same bank = then probably TDC sensor, Dist cap/rotor/button, Coil, or Coil wire for that bank (and some of those could also be swapped to see who is the problem - but just a visual look inside the dist caps can be informative).
    Good Hunting!
     
    thorn likes this.
  4. Speedsterbeast

    Speedsterbeast Rookie

    Nov 20, 2018
    31
    Thunder Bay Ontario
    Full Name:
    Cory Zyromsky
    #4 Speedsterbeast, Jun 13, 2020
    How would I know if the misfire moves to the other bank?
     
  5. thorn

    thorn F1 Rookie
    Silver Subscribed

    Aug 7, 2012
    3,324
    Tallahassee, FL
    #5 thorn, Jun 13, 2020
    Do you have any equipment - like a meter/scope with inductive clamp, that you can use for testing while driving?
     
  6. johnk...

    johnk... F1 World Champ
    Owner

    Jun 11, 2004
    11,190
    CT
    Full Name:
    John Kreskovsky
    #6 johnk..., Jun 13, 2020
    Tack runs off the 1-4 digi. If you swap digis and the car still acts the same but the tac doesn't die then the problem moved with the digi to the 5-8 bank. If thr tac still dies, it's still the 1-4 bank.
     
  7. Speedsterbeast

    Speedsterbeast Rookie

    Nov 20, 2018
    31
    Thunder Bay Ontario
    Full Name:
    Cory Zyromsky
    #7 Speedsterbeast, Jun 13, 2020
    I see. Thanks John. I'll try that first.
     
  8. Speedsterbeast

    Speedsterbeast Rookie

    Nov 20, 2018
    31
    Thunder Bay Ontario
    Full Name:
    Cory Zyromsky
    #8 Speedsterbeast, Jun 13, 2020
    Thorn- I do not.
     
  9. Speedsterbeast

    Speedsterbeast Rookie

    Nov 20, 2018
    31
    Thunder Bay Ontario
    Full Name:
    Cory Zyromsky
    #9 Speedsterbeast, Jun 13, 2020
    Thanks Steve. That all seems like simple steps for trouble shooting. Much appreciated!
     
  10. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
    1,602
    California SF bay area
    Full Name:
    Paul
    #10 kcabpilot, Jun 14, 2020
    Yup definitely not a fuel issue. Jiggle, reset, clean the electrical connections to the coils (especially 1-4)
     
  11. Saabguy

    Saabguy Formula 3
    Silver Subscribed

    Mar 28, 2012
    1,785
    Shreveport, LA
    #11 Saabguy, Jun 14, 2020
    Rule of thumb, "fuel" problems are mostly electrical and visa versa.
     

Share This Page