1991 audi 80 5 cylinder, auto, non-quattro


#1

I installed new plugs, plug wires, rotor and cap. I had the car detailed it hasn’t run right since! I picked it up from the detail shop with a strange clicking noise under the right dashboard (like a stuck relay) the car got running great for about 3 hours and now it runs poorly at best, I have replaced the fuel pump relay, the fuel pump, the fuel distributor, the low temp sensor, and have tried different computer moduls, distributor and cannot get these thing running better. Two garages and 6+ months later nobody can figure it out. Anybody out there, that can help???


#2

I’ll put money on the fact that the strange clicking noise has nothing to due with your problems. The detail shop may have dropped something down the heater or defroster vent that is now rubbing against the blower fan.

First thing I would check for is vacuum leaks. In particular, look at the rubber/plastic duct work that runs from the fuel distributor up to the throttle body as well as the fuel injector o-rings (they’re extremely prone to hardening and cracking).
If that doesn’t do it, check the fuel pressure AND the control pressure. You’ll will need a specialized pressure tester that is designed for the Bosch CIS-E system that is on this car.


#3

OK, what I think I might do is take it to my local Audi dealer, and let them have 2 hours to diagonois it. Do you think that would be wise?

Incidently the clicking noise stopped within the next 2 days. And maybe the detailing had nothing to do with my problem, just the timing of it all?


#4

Oh, the other thing is I also replaced the fuel filter, the guy who has it now (has been an Audi mechanic for 21 years) said it has good fuel pressure, and supposedly he has looked the car over numerous times for a vacuum leak and a ground or broken wire. The car will start after a bit of cranking, and sometimes it runs awesome, but with in anhour it’s back to running likes it is onl;y running on 2 cylinders. It runs real rough. I also understand that there is no code reader involved here, what would the Audi shop do to come up with the problem? They cclaim to give them 2 hours and they’ll be able to figure it out. Your thoughts?


#5

“the guy who has it now (has been an Audi mechanic for 21 years) said it has good fuel pressure”

Did he take the pressure measurement while the car was running on five cylinders or two cylinders?
If the car was running on five cylinders while he measured the pressure, then I wouldn’t be surprised that it was good.
Have him verify that the differential pressure regulator is working correctly. Your new fuel distributor may have come with one. If so, skip this step.

Try disconnecting the oxygen sensor while it’s running rough. Just a thought . . . might give you a clue.

If everything on the fuel system checks out fine, then start looking towards the ignition system. Bad coil or hall sender perhaps.


#6

Well, I just talked to theis guy, I ran everything by him that you suggested and he claims to have done all of that, and also that if it was the coil or the hall sender then the car wouldn’t start. He claims the car has good spark, and it runs good sometimes but for the most part it runs poorly. He told me to come and get it and do whatever I want. That is why I thought I should take it to an actual Audi dealer and see if they can figure it out. What else would you recommend, and what are your thoughts regarding the Audi dealer?
Thanks for your advice!


#7

There’s a good chance the mechanics at the audi dealer will be unfamiliar with how this fuel injection system works. It hasn’t been used in production in over 14 years. But, it’s probably worth a try anyway