RE ; MAC11 update

[Louis-Alain Richard]

Sorry for the repetition Rick, I just re-read your original post, and these
things were already covered by you. 

Now, I don't know the MC1 configuration, but on the urQ, there is an
ignition module located in the top of the glovebox that provides the spark,
while the MAC-02 provides the ignition table. That module is grounded on the
top of the intake manifold, and breaking that wire result in a dead engine
(ask me how I know). Is there such a device on your car ?

There is also another possibility : Geraint here has a Porsche 964 that had
an intermittent ABS malfunction light. After much hair pulling, the solution
came from a forum where he found that a bad ignition coil, there is 2 on
this engine, would cause a parasitic current that would trigger the ABS
light. Very strange situation, but indeed after replacing both coils and
dizzy caps+rotors, the ABS light is now dead quiet. Is there a
high-impedance device that could confuse the ignition in your car ?

Don't give up, we're with you ! :-)

Louis-Alain



> -----Message d'origine-----
> De : Rick Houck [mailto:rhouck at neo.rr.com]
> Envoyé : 9 septembre, 2008 22:38
> À : Louis-Alain Richard; cody at 5000tq.com; 'Ben Swann'
> Cc : quattro at audifans.com; 'P Cole'; 'Ado Sigal'
> Objet : Re: RE ; MAC11 update
> 
> Louis-Alain,
> 
> I have read through the suggestions on SJM's site, and feel that I have
> tested or eliminated things sufficiently, but since I have not yet found
> the
> problem, I am obviously missing something. Opening the ECU was one of the
> earliest things I did, since the problems started at a rainy track event.
> I
> found no evidence of moisture or water tracks, but dried it out in the sun
> just to be sure. After no improvement, I ordered a spare ECU and
> distributor
> from Force5.
> 
> I have at least two of each of the major ignition and mechanical
> components,
> and I have tried about every combination of ECUs,plugs, wires, dist caps
> and
> rotors, complete distributors, coils, flywheel RPM and TDC sensors, knock
> sensors, fuel filters, and COMPLETE ENGINES. Nothing so far changes the
> situation except turning the distributor counter clockwise.
> 
> It seems unlikely that I have two identically bad components, but maybe I
> do. It also seems unlikely that both engines have a sheered key on the cam
> or crank, but the relationship between the distributor rotor and the TDC
> trigger is good enough for starting but not for running at higher revs.
> The
> ECU is getting full voltage during the problems, and I also have confirmed
> ground (don't remember pin numbers now). As Ben says, ignition seems to be
> satisfied enough to start and run properly for the first 25% of the RPM
> range.
> 
> Cody, I have some very loud exhaust backfires (3" from turbo back with no
> cat), but others come back into the intake system. I have been concerned
> that I may damage my turbo or intercooler plumbing. This indicates to me
> that the timing is getting confused at some RPM, or that the plug is
> firing
> at an improper time because of arching. When I changed plugs last week
> (again) the Bosch's had a dry carbon coating, but IMO nothing out of the
> ordinary for an engine running at low speeds. New plugs are NGK's, but
> results are the same.
> 
> Rick
> about to give up
>