Seeking help with 2002 Buick 3.1 crank no start diagnostic next step.

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  • July 18, 2025 at 11:42 am #313421
    Seele7
    Participant

      No Codes present
      Has 3 new coils on ICM that was tested and passed @orielys
      Compression is 195+/-
      New spark plugs gapped at .060″
      New fuel filter
      Fuel pressure 55psi when commanded on then 50psi after 2second run time. Holds pressure.

      I’ve been chasing missing CMPSignal for some time now with no success.. when monitoring with ThinkCar 689bt I get all the modules and monitoring the live data has shown a consistent “no camshaft position signal present” in every test I have done except the first time when I was able to record it for the one second it ran.

      AllDataDIY says the CMP is not used for ignition start up timing.
      the following is from the diagnostic page..CIRCUIT DESCRIPTION
       The ignition control (IC) module has independent power and ground circuits. The circuits between the IC module and
      the powertrain control module (PCM) consist of the following circuits:
       ^  The IC timing signal
       ^  The IC timing control
       ^  The low-resolution engine speed signal
       ^  A low reference signal
       The ignition control (IC) module sends 3x signals to the powertrain control module (PCM). The IC module controls the
      timing advance during engine cranking. The timing advance changes to PCM control after the following actions:
      ^  The PCM receives the second 3x signal.
       ^  The PCM applies 5 volts to the IC timing signal circuit.
       ^  The timing advance switches to PCM control.

      All I know is that sometimes it will crank normally and other times it sounds like doo doo caw caw.

      I have the tools to check things out and effect repairs for most things but I’m weak on how newer stuff is integrated.

      Items that I have for testing..
      Pico 2204
      MicSig VATO 4ch USB
      40/400v amp clamp
      FSM and AllDatadiy for reference

      At this point I’ve gone through the different symptom and diagnostics diagrams only to hit dead ends and am uncertain which direction to turn.. what are the most important things to test or retest?
      Which Waveforms would be best to share with you?

      July 19, 2025 at 11:33 am #313452
      Seele7
      Participant

        Fixed it… Nevermind

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