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    Results 1 to 6 of 6
    1. #1
      Join Date
      Sep 2019
      Posts
      4

      PCM refuses to deliver spark

      Hi,
      I am currently having a problem with no spark and no injector pulses on my LS1 -99. Here are some facts and background:

      - One day recently it simply refused to start.
      - The car is a Chevy Business Coupe -40 with 5.7L LS1 -99 and 4L60E.
      - Wiring harness is PSI HAR-1016.
      - VATS are disabled.
      - It has been running fine for years and no modifications made lately.
      - The battery is fresh and it is cranking as it should.
      - The fuel pump is priming as it should and I have pressure in fuel rails.
      - All fuses and relays checked and are ok.
      - No spark at spark plugs while cranking!
      - No pulse signal to the injectors while cranking!
      - I have a good 12v from the ignition relay at the fuse/relay center of the harness.
      - The HP tuner communicates fine with PCM and I can read the tune and scan for error codes.
      - The codes I get from scanning is P0102, P0203 (I'm running in SD mode without MAF sensor), P1571(pending,history),P1689(ses,current).
      I have allways had these codes and I don't think these are related to the problem.
      - I verified with the HP tuner/scanner that the crank and cam sensors are giving signals as expected.


      Now I'm completely out of ideas. Any hint or suggestion on what to do is appreciated!

    2. #2
      Join Date
      Sep 2010
      Location
      Beach Park IL
      Posts
      2,838
      Country Flag: United States
      Do you have 12 volts at the fuse/relay center _while_ cranking?
      Donny

      Support your local hot rod shop!

    3. #3
      Join Date
      Sep 2019
      Posts
      4
      Quote Originally Posted by dontlifttoshift View Post
      Do you have 12 volts at the fuse/relay center _while_ cranking?
      Yes

    4. #4
      Join Date
      Sep 2019
      Posts
      4
      Quote Originally Posted by dontlifttoshift View Post
      Do you have 12 volts at the fuse/relay center _while_ cranking?
      I was wrong Donny. Checked more carefully today and while cranking the +12v feed to both coils and injectors disappears!

    5. #5
      Join Date
      Sep 2019
      Posts
      4
      Problem solved! Bad ignition switch block on the steering column.

    6. #6
      Join Date
      Sep 2010
      Location
      Beach Park IL
      Posts
      2,838
      Country Flag: United States
      Cool!!

      Donny

      Support your local hot rod shop!






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