ESC diagnostic

am018 am018 at post.almac.co.uk
Sat Sep 5 11:01:31 GMT 1998


Try (lightly) hitting the block with hammer ner the sensor with engine idling on some systems  it will cause the idle speed to hunt.

Joe Boucher wrote:

> I don't think my ESC module is working.  I was experiencing knocking, so I retarded my timing.  Then I thought, that ain't the way this is supposed to work.  So, I dug in the factory manual, and
> found some diagnostics.
>
> I thought the system worked by grounding a wire from the ESC module through the knock sensor.  The one in the Suburban was new when I installed the engine.  The diagnostics said to disconnect
> the knock sensor and hook that wire "momentarily" to a 12 volt source while watching the timing mark.  Well, I tried both ways, 12 volt and grounding,  and didn't notice any difference in the
> timing.
>
> There was voltage at the ECS module, so it is powered.
>
> I forgot to hook the knock sensor up and the next day the check engine light came on.  I rehooked the wire up and started the engine and the light was out.  I was rushed and didn't use the ALDL
> to look for trouble codes.  I'm assuming the ECM somehow figured out the wire was disconnected, but how if the module isn't working?
>
> Any suggestions?
>
> Thanks,
>
> Joe (Looking for fly turds) Boucher
> '70 RS/SS Camaro  '81 TBI Suburban
>




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