Re: Continuing saga of Ur-Q with no spark

[Robert Houk - SMCC Bos Desktop Hardware <rdh@UrQ.East.Sun.COM>]

   Maximum frustration! My Ur-Q still won't spark. I've replaced Hall Effects 
   Distributor Module and tonight I replaced Ignition Control Module.

   Three questions:

   1. Local supplier did not reference an Ignition module for 83 TQC in his parts 
   inventory but he did have one for '84-86 5000 Turbo. I optted to try the 5000 
   Turbo Module. Does anyone have any information on compatibility/incompatibility 
   of 5000T modules with Ur-Q?

Audi/VW (/Porsche?) all use the same (or a set of same?) little ignition
modules in those years, so the odds are very good that what you have is
OK (you have the old one, right? Just take the number off of it...)

[We are talking about the little black box -- 'bout the size of a small
padlock -- with, what, 5 or 6 pins, mounted to a heat sink underneath
the dash, in glove box, a foot or so from the main engine computer, right?]

   2. I now get a weak spark just after I stop cranking. I recall a recent thread 
   on low voltage in Ur-Qs causing this. Can you repeat directly to me (to 
   eliminate redundancy on the Q-list)

Pop the ECU cover, and see what voltage you have on connector pin 14 (+12
to the ECU) to, say, pin 18 (ground within the ECU itself). Both of these
pins are on the "top" side of the connector, and easy to get to. Pins 9
and, I think, 1 are main ECU grounds (lead to chassis ground), measure the
voltage from them to chassis ground -- should hopefully be only a few
random millivolts...

If you're adventurous, measure the voltage on the pressure transducer,
one of them should be +8 (green or white, I think).

The +5 logic can be checked on most any of the ICs; for example the 6840
chip pin 14 is +5 supply, the 2532 (ROM) chip is pin 24, or the 6802 cpu
is pin 8.

By the way, don't be surprised (alarmed, panic-stricken) when you measure
0V everywhere on the board -- it is "conformally coated" with sealant
glop to protect against moisture/etc; you will have to [carefully!] scrape
through the glop coating to get to the pin metal to measure the voltage...

   3. In dropping (almost literally) engine back in I hit the original coil. As 
   insurance I replaced the dented old coil with a Lucas "Super Coil."  Resistance 
   measurements are not exactly Q specs. They call for primary resistance of 1800 
   ohms I get 2200. They call for .60. 85 ohms across secondary and I get 1.3. Will 
   this affect spark?

I wouldn't think so, but dealing with the Audieties, you never know . . .

I really hate to tell ya this, but it's sounding more and more like your
ECU may have bitten the big hairy one. But before you decide to shoot
yourself as the less-painful alternative, make sure the sensor signals
are getting *into* the ECU -- measure them at the connector pins inside
the ECU (as long as you have it out and apart on your passenger floor).

Any one of half-a-dozen signals gone AWOL within the wiring harness will
cause the ECU to say no. See if the ECU is pulsing the ignition module
(pins 2 and 17 on the connector go to the ig module, one is I think
+12 (?) and the other is the trigger signal to fire the spark.

Got a scope handy?

If you can get together with any of the other fools in your area, try
swapping ECUs and see if you get spark...

					-RDH