ESC diagnostic

[Shannen Durphey]

Lessee, knock box maintains 5v on sensor line.  Sensor produces a/c
voltage, so any change from 5v within reason means knox.  Mebbee test
lamp to battery positive and sensor line, in rapid on/off fashion will
give desired results.  It's what I'd try...12V seems high.
Shannen

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