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1991 Audi 90 Quattro 20V Issues

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Old 05-08-2012, 03:53 PM
troysherk's Avatar
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Default 1991 Audi 90 Quattro 20V Issues

I have some problems I'm working on right now. I'll go through them one-by one. Here is the list so you can skip ahead if you want:

-Engine idle while cool/loss of power under full throttle
-Hydraulic issues
-Ignition switch
-Handbrake

Starting with the idle problem, the symptoms are that the engine will start while cold, but will not maintain an idle on its own. My starting procedure is to put my foot on the brake since the parking brake doesn't hold it, put the clutch in, take it out of gear, switch feet with left on brake and right on gas once it starts up. If you let it warm up by keeping the revs between 1 and 2k for a few minutes, it warms up to the second line on the coolant gauge and idles fine from there on out. But then it runs out of power around 5-6k rpm (it seems to vary depending on the day). I've heard others refer to these as "open-loop" mode, but I'm not 100% sure what it means in terms of what causes the differences between open and closed loop modes.

Next, the hydraulic system in this car has been a huge pain in my neck ever since I bought it. I attempted to have the pump rebuilt last summer, but they sent it back saying they couldn't rebuild it due to its type. There are no replacement parts available online either from what I have checked (let me know if you know of a reasonable replacement pump). I think that's my problem, but I'm not sure. Could be they "bomb" too. The steering does have assist. That power assist gets better as the RPM rises, which makes me think the pump is weak. The other symptom is that the Antilock Off light illuminates after a short distance of driving. The brake pedal is often hard for the first couple of stops, but then I feel it loosen up under my foot. I have drained and flushed the system. Originally, I didn't have assist at all for the steering, and that's when I sent the pump in. When I got it back and reinstalled it, the power assist came back to what I have described.

The ignition switch isn't what I would consider a huge issue, but it is an annoyance. The original switch was faulty, so I replaced it, but I can't figure out how to get the switch itself to join up with the lock cylinder without tearing the whole dash apart. I can access it from underneath, but not actually remove it or put in the new one. Any ideas?

In comparison to the other flaws, the handbrake is a minor annoyance too, but it would be nice to fix it. Maybe I just need new springs. I adjusted the springs that were there, and the handbrake was functional for a while, but the calipers would hang up, which is pretty inconvenient. It doesn't grab the discs at all now.

Thanks for any help!
 
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