[V8] ECU grounding, etc. (abridged)

[Coleman, David]

If you didn't feel like reading my lengthy post, the ultimate question
is: where does pin #54 of the ECU harness connector get its ground?

And as an FYI, all troubles are present with the g62 ECT sensor and the
02 sensor unplugged or plugged in...



> -----Original Message-----
> From: v8-bounces at audifans.com 
> [mailto:v8-bounces at audifans.com] On Behalf Of Coleman, David
> Sent: Monday, October 10, 2005 2:42 PM
> To: v8 at audifans.com
> Subject: [V8] ECU grounding, etc.
> 
> So yesterday I finally got a chance to spend a few hours w/ 
> my poorly-running V8.  Here's a quick recap:
> 
> + Car starts only after a few 1-second cranking sessions.  Won't start
> w/ extended cranking.
> + Once warm, idle begins to fluctuate wildly (0-1500 rpm) until engine
> dies
> + Engine suddenly bogs down to the point of killing the motor if
> anything close to WOT, either revving or driving.  Sort of 
> like I'm mashing the brake pedal while keeping the throttle open
> + Car runs WAY too rich, in all running/driving circumstances
> 
> I've replaced the FPR and spark plugs.  From there:
> + Code consistently shows 2324 (bad ECU ground, MAF wiring) Running 
> + diagostic output tests indicate all injectors click, ISV
> actuates, but carbon canister solenoid no good
> + Replaced canister solenoid and associated vac hose clamps, 
> now clicks
> away during output tests.
> + About this time chunks of ceramic began appearing on the 
> ground behind
> tailpipe
> + Cats wasted.  Gutted what was left, replaced center 
> muffler, left rear
> section alone (verified no cat innards got caught in there).
> 
> No change... this brings us to yesterday.  Test light and 
> multimeter in hand, I went through the manual's check process 
> for ECT sensor (G62), O2 sensor, and MAF sensor -- all failed 
> the checkout, with all blaming the ECU or its wiring.
> 
> So I pulled the ECU harness connector away and did two checks 
> before it was time to call it quits:
> + ECU voltage supply check asks to confirm ground at terminals 10, 14,
> 19, 24, and 54 of the harness connector ---  All were good 
> except at 54.
> + I also picked back up on the MAF sensor check procedure, which was
> asking to verify continuity between ECU harness connector 
> pins 19 & 37.
> No good.  Blames an apparent short between ecu pin 37 and 
> terminal #5 of the MAF sensor connector.  So far no luck 
> finding a short...
> 
> So the upshot is: how does terminal #54 of the ecu harness 
> connector get its ground?  Any other thoughts?
> 
> Delirious in Delaware,
> 
> DaveC.
> '91 V8 5-speed
> 
> 
> 
> 
> 
> 
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THE INFORMATION CONTAINED IN THIS MESSAGE AND ANY ATTACHMENT MAY BE PRIVILEGED, CONFIDENTIAL, PROPRIETARY OR OTHERWISE PROTECTED FROM DISCLOSURE. If the reader of this message is not the intended recipient, you are hereby notified that any dissemination, distribution, copying or use of this message and any attachment is strictly prohibited. If you have received this message in error, please notify us immediately by replying to the message and permanently delete it from your computer and destroy any printout thereof.