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Re: Knock sensor woes



There's also another problem. The code is supposed to run an ESC test during
fixed throttle warm run. If the engine DOESN'T ping during this test, the
EST code
will set. Run this car with 87 octane and see if the problem goes away -- OR
just upgrade to the false EST 43 PROM.
Lyndon...
-----Original Message-----
From: D Kunnath <djktno@engin.umich.edu>
To: gmecm@diy-efi.org <gmecm@diy-efi.org>
Date: May 31, 2000 8:54 PM
Subject: Knock sensor woes


> Hey all,
>
> I've posted in the past to get help on other issues in the past few years,
>and while I stay in the shadows most of the time, the wealth of knowledge
>around here is amazing, so I'll have at it again if you all don't mind.
>
> I just picked up another Camaro (91 Z28, 5.0TPI A4) out in California, and
>like with any "new" used car, there are always a few bugs.  Right now I
>can't seem to clear a code 43, relating to the Electronic Spark Control
>system in the car.  This particular ECM ('730 / ''727) has the ESC module
>moved into the mem-cal, as far as I can tell from the GM Service Manual, so
>I am assuming that the memcal is good because everything else works fine.
>
> I disconnected the knock sensor when I had the car jacked up and I
>connected an AC voltmeter to the sensor along with grounding to a known
>good groundpoint.  Running the engine at idle produces no AC signal on the
>voltmeter.  I figure that is normal considering the no-load
>condition.  Revving the engine up (engine IS in closed loop) produces no
>signal either.  Now I'm not sure about this.  Is this a normal
>condition?  I traced the sensor wire back to the ECM and it is fine, and
>not running close to spark plug wires.  The engine runs very smoothly both
>under idle and under load.
>
> The only other thing I can think of is that the car has been in California
>its entire "life", and it does have California emissions.  It has now been
>transplanted to Michigan.  Could there be a certain something with
>that?  I've been running 89 octane gas from Amoco, which has always been
>fairly good in my other TPI cars.
>
> Any ideas, inputs, points of stupidity that I may have missed?  I wish I
>had a scantool to peek inside the brains, but I know that all of us who
>don't wish for the same.  Whatever you guys can throw at me, I'm all
ears...
>
> Thanks,
>
> DK
>
> 91 Z28 Convertible, 5.0 TPI A4 2.77
> 86 IROC, 5.7L TPI, T56 6-speed, 3.73
>
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