The ECM is 1227747and was remanufactured although I'm not sure which "brand" it is. The PROM is modified by the guy who sells the kits. I don't know exactly how it's modified (which data) but the seller asked questions about engine size, transmission, A/C, thermostat temp, 2bbl, factory timing spec, idle RPM, etc.
The original chip the seller made for my car was not a good match and I was having additional problems early on. The idle speed was too high in the chip so the computer was trying to compensate for what it thought was low idle. We fixed that with a replacement chip and the car is running much better than it did originally. I didn't put all that into my original post because I didn't want to confuse the issue. However, the check engine light and problems I described in the posts above are persisting.
I looked at Summit Racing for a replacement ECM. They have a 1227747 replacement from Cardone for $74 and a replacement from AC Delco for $107. Both are remanufactured. I'm leaning toward AC Delco although it goes by a newer part number 88999146. I guess the newer number supercedes 1227747.
The seller of the TBI kit is willing for me to return the ECM and he will put it in his truck and run it for several days. That should verify whether the ECM is at fault. While I'm appreciative of the seller's willingness to help that whole process could take as long as two weeks - sending, testing, returning.... On the other hand, I can have a replacement ECM from Summit or any number of other parts dealers today.
A few more details about the system I installed:
- external electric fuel pump is providing 12 psi to the TBI
- MAP sensor
- 180 degree thermostat
- A/C compensation increases RPM in an attempt to overcome the huge load of the A6 compressor
- engine coolant temperature sensor is in the block side of the water (not the radiator side)
- installed new small-cap electronic distributor
- TPS is set to 0.50 volts but sometimes varies a small amount (0,49 - 0.52) after driving the car. It doesn't seem to always return to 0.50
- when the engine is idling normally the IAC is anywhere from 0 to 10, sometimes a bit higher
- the VSS is disabled, as is the knock sensor, any other sensors not mentioned above have been disabled.
- ECM is mounted in the cab, and it has plenty of air around it and is easy to access (it's not way up under the dash)
- the two relays are attached to the bottom of the ECM with adhesive. I did not screw the relay tabs to a piece of metal
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