GM 4.3L CMP retard PID fault

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  • jpgarrido
    Junior Member
    • Dec 2006
    • 10

    GM 4.3L CMP retard PID fault

    Hi fellow techs.

    If you get a 4.3L V6 on a GM vehicle and the CMP retartd PID reads outside of 0 degrees +/- 5 you may want to pull the distributor and inspect the drive gear, the entire drive gear as in 360 degrees of it.

    I took a look at one today that had a P0016 CMP/CKP correlation DTC. The CMP retard PID read -19 to -20 degress. I pulled the distributor to look at the distributor drive gear. It looked fine, till I rotated it to the other side, Yikes! Thought you might enjoy the Know Bad pics.

    A new distributor and the CMP PID was at +4 degrees and no more codes.
    Attached Files
    Jim
  • john4842
    SDE Member
    • Oct 2006
    • 38

    #2
    gear it up

    thank's for sharing your info.good pic's

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    • INLANDSMOG
      Banned
      • Oct 2006
      • 24

      #3
      Great post, Thanks.

      Comment

      • tenfooter
        Senior Member
        • Apr 2007
        • 101

        #4
        Other causes?

        I have seen this in about 6 different gm 4.3L engines. Three out of six had distributor gear wear issues. One was an improperly installed distributor. And two are still going down the road after modifying the distributor holes. The modified distributors I suspected timing chain wear but when reversed the distributor showed little wear. Has anyone seen camshaft gears wearing on this engine? Or possible bushing wear allowing improper alignment of the gears?

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        • tenfooter
          Senior Member
          • Apr 2007
          • 101

          #5
          Some other useful tidbits.

          I have found that a misfire can occur if the cam offset is around 15 degrees. This will cause the ignition advance to go wide out off idle this in turn drives the coil output KV's through the roof causing a misfire due to inadequate spark. On an oscilloscope, in parade mode,it is really distinct when the KV's go super high at around 1200 rpm. Look for normal KV's at idle that jump for no apparant reason around 1200 rpm on slow acceleration. I would include nice photos but sun 1215 doesn't print them.

          Comment

          • INLANDSMOG
            Banned
            • Oct 2006
            • 24

            #6
            Also make sure the driven gear on the dist isn't installed 180 out. Seen this one last week.

            Comment

            • travsirocz
              Junior Member
              • Jun 2007
              • 4

              #7
              there are many causes for 4.3 cam codes. here is a crank shaft position sensor problem. http://www.dewitzauto.com/1999_GMC_Safari.html
              Travis Dewitz
              Dewitz Truck & Auto Repair
              Dewitz Diagnostic Solutions
              Mobile Automotive Diagnostics
              www.dewitzauto.com

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