Backfiring question... annoying..

Discussion in 'Technical' started by woody_z32, Jul 27, 2005.

  1. woody_z32

    woody_z32 New Member

    Well after the sucessful completion of my 100k and plenum pull i have noticed one little annoying thing... when cruising along and i release the accelerator pedal and the car is decelerating when the revs slow down between 2000 >> 1700rpm the car backfires and makes popping noises etc.. what could this be? it only happens between these revs and only when slowing down... just curious on how to fix it cause its quite embarassing. :(
     
  2. K-zed

    K-zed Secret Squirrel

    Timing ... out?

    How accurate was yr marking & re-positioning of belt?
     
  3. Planet Z

    Planet Z Member

    Check all ya coilpack and especially injector connectors!

    Especially after the plenum pull!
    Cheers
     
  4. woody_z32

    woody_z32 New Member

    I'm quite sure its not a coil pack or injector problem, as then the car

    would be runing shite all the time. However as rob suggested possibly my timing may be out... there were half-a-dozen of us present when that was getting done.. and i think we did a good job.. on the drivers side the cam gears seemed to be out by 1/2 a tooth so there was nothing that could be done.. also when i was adjusting the timing when i first fired it up.. the markings that i made on the CAS which i had set it up to the car was waaaaayyyy advanced... like 25-30 deg btdc.. so i have pulled it back quite a bit.

    any other suggestions?
     
  5. zed4life (zedcare.com)

    zed4life (zedcare.com) Ω vicarious zedder Ω

    Long shot but service manual states check Coolant Temp

    Sensor and circuit. Sensor should Ohm out thus:

    o 2.1-2.9 kOhm at 20C (68F)
    o 0.68-1.0 kOhm at 50C (122F)
    o 0.30-0.33 kOhm at 80C (176F)

    Check for code 13 indicating circuit fault.

    PS: I'm more inclined to agree with Rob - timing out...
     
  6. Ns-Zed

    Ns-Zed Member

    RE: Backfiring

    This is a common problem for all types of cars that have aftermarket "Performance" chips installed...which rely heavily on advancing the timing. Combine this with a pod and you have serious backfiring...well popping anyways. I personally experienced this on my previous car, and know many people that have had the same thing.

    Its a timing issue for sure, but unless the timing is way out, then there is no real need to retard it, unless the popping is annoying-which it is.
     
  7. K-zed

    K-zed Secret Squirrel

    Someone else may enlighten further, but ...

    ... it does sound as if the timing belt is out by a tooth as all gears should have re-aligned 100% without altering the CAS.

    It may be necessary to turn over the motor several times to achieve correct alignment if cams have moved during the service.
     

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