Request: 3A Engine ECU Connector Pinout

[thunderpumpkin]

Hi all, new member here and apologies in advance for the long read...I've tried to summarise my diagnosis so far! I drive an Audi B3 Coupe 2.0 with the 3A engine 1990 UK model (it's been in the family since the 90s) and I'm hoping that someone may have a pinout for the 35-pin 3A Motronic connector.

I dived into trying solve some idling issues following a leaking DPR which was replaced. Also replaced the following with matched part numbers and genuine Bosch:

1. Coolant temperature sensor (old one was over 15k Ohms at room temperature)
2. Oxygen sensor (old as the hills)

Further testing revealed the oxygen sensor is not receiving power to the sensor heater, the idle microswitch has high resistance with a closed throttle and the ISV does not receive a voltage which is probably explained by the failed microswitch not telling the ECU to idle. Vacuum leaks should not be a problem as I've smoke tested and found the injector holder o-rings needed replacing, one holder is cracked but a replacement is on its way.

After replacing the DPR, coolant temperature sensor and oxygen sensor the car would start idle at around 1,000rpm and then settle to just above 800rpm. While all seems okay, the DPR current fluctuates from 6-15mA not 0-5mA and there is no power going to the oxygen sensor heater which would explain the problem. I am not able to get a sensible voltage from the oxygen sensor either, the voltage is around 5mV which would suggest a very lean condition. I've also managed to pull error codes from the 2x2 diagnostic connect under the steering wheel, 4431 which suggests an ISV problem or a break in the cable.

Also since trying to go through the cabling, I've gone from having a steady idle to the the car not being able to idle at all. I had richened the replacement (second-hand) DPR screw since it was not able to idle when warm. Yes, perhaps I should have not tinkered but I also have a couple of Mercs with KE-Jetronic and I've gotten curious about the system so hence the tinkering

Since I have a number of electrical issues with the engine harness, I'm hoping someone may have (or point me in the direction) the pinout of the connector for the 3A Motronic ECU so I can at least rule out a problem with the harness as no power is going to the oxygen sensor heater and the ISV.

Thanks!