90 C4 all of a sudden running rich

[dkcaims]

...also posted on R-list.

A little background first...

The car is supercharged.
Recently has a new FTC1 (controls 7th injector & retards timing), a PSC1 (signal modifier to accommodate larger injectors, 30lb).
Also installed was a dashdaq monitoring AFR, Fuel Pressure and Boost.

Once everything was wired up and fined tuned the fuel maps, it ran fantastic for the last month, including immediate start-up and idle. WHAT A DIFFERENCE !!!
Note: o2 has been disconnected since tuning and ran great for the last month.
AFR's were consistently 14.2-14.7 at idle and under light load.
AFR's were 11.5-12.0 under full boost.

Just a couple days ago when starting, AFR's were just where the always are at start-up, 14.5-14.7
... but after 15 seconds or so at idle, the AFR's drop to a low of 10.3 and don't go over 11.0 even during a short drive around the block.

What I've checked so far...
Fuel Pressure good
Distributor belt good
Cleaned ISV
Pulled new injectors and had them checked. Thought maybe one or more was stuck open. All checked out fine, re-installed. Also checked 7th injector in case it was firing at idle, but it's not.
Re-connected O2 sensor, but same result.
Checked the coils... runs the same on either coil.

Vacuum leak somewhere ?
Some kind of fault with the AFM ?

Any thoughts? I'd like to have this resolved before the Porsche Parade.

Thanks
Derek

[dkcaims]

UPDATE...

Someone suggested the Head Temp Sensor.
Can't find my multimeter at the moment though.
I used a jumper on the plug for the head temp sensor going back to the DME and it ran the same as it does connected to the sensor.
The question is... should it? Did I find my problem?

Found the mulitmeter... engine was run for 30 seconds an hour ago and I just now measured the resistance.
It measured .839 ohms.
I'll check it again in a few hours, but I think it should be much higher, correct?

Car is gathering dust... ANYONE ???

[cjoenck]

Here you go:

[dkcaims]

No one at all?
My regular tech is on extended vacation, so I went to another highly recommended tech nearby and he says 25-30 hrs to diagnose. Does that seem an appropriate labor charge to diagnose a rich running problem? 3 grand ?
I'm about ready to sell the car, but who would want a car that does not run properly.
It's a shame, this car has had $57,000 in repairs since 1997, plus 12k this year by me and I can't drive it because it runs too rich.
I guess they were not meant for driving, only for lookin at !


Will have an oscilloscope by Sunday if anyone has any ideas.