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Oct 2, 2011 | 03:37 PM

Mikechips03

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Please Please someone help!

Hey there guys I have a 1990 Audi 90 quattro 20v that is driving me insane! I bought the car a week ago knowing that it had a bogging issue. I didnt think anything of it and thought it would be an easy fix. It starts really rough and i have to pump the pedal to get it to start which doesnt make sense to me because it is only adding air.... It will bogg down in any gear from 1000 to 3000 rpms and it seems to be missing a lot of power. I have taken it to 3 shops and no one can find the issue. The plugs and wires have been changed and so have the cap and rotor. It doesnt have a vacuum leak and the fuel pump is coil is good. One mechanic thought it was the fuel pressure regulator but i dont think so... they are supposed to last forever. The problem is the car has no check engine light and no ones diagnostic tool will work on it

If anyone has any input at all i would greatly appreciate it! Thanks.

Oct 2, 2011 | 05:37 PM

grillage

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Joined: Sep 2010

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From: Cincinnati OH

I've had similar symptoms with a plugged exhaust. Had a catalytic converter come loose and plug in the pipe.

Oct 2, 2011 | 07:30 PM

yodasfro

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Joined: Mar 2005

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From: CT

Could be the 02 sensor first thing I'd do is check the fault codes.
http://www.20v.org/

Oct 2, 2011 | 09:14 PM

1993audi90

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From: Pittsburgh, PA

Quote:

Originally Posted by grillage

I've had similar symptoms with a plugged exhaust. Had a catalytic converter come loose and plug in the pipe.

here. here. I've experienced this first-hand. But the car tends to run hot with plugged/broken up CATS. Wonder if moisture is getting into something? Have you done a vacuum leak down test?

Oct 2, 2011 | 10:41 PM

bwkdotcom

Audiworld Junior Member

Joined: Nov 2010

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From: Los Angeles CA

I would 2nd the check for a plugged cat. Car would barely get over 30-40mph, and take forever to get there. I had to take a dremel cutting disk to the exhaust to cut a slot in front of the cat in order to reduce backpressure and get the car moved.

Oct 4, 2011 | 05:43 PM

Mikechips03

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Pretty sure its not a plugged cat... it accelerates up to over 100.. doesnt backfire or anything like that. more of just a hesatation feeling and loss of power. could it be something with the fuel system? Fuel pump or filter?

Oct 5, 2011 | 07:11 AM

Lago Blue

AudiWorld Senior Member

Joined: Apr 2007

Posts: 1,532

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From: Canada

Perhaps it is something simple...

But do the LED code pull. If you can't build such a thing, you can buy an electrical LED test light that will be suitable.

You seem to have fuel and spark. Is the car running especially hot like it is working too hard? If your cat/exhaust is in fact clear (a muffler shop may help you there), your issue(s) may be up top. If you have to "add air" to achieve a start;

- was the car sitting for some time before you bought it?
- is the gas fresh?
- has the car been modified?
- is the air filter element stock?
- is the air filter box OEM original?
- is the air filter element clean?
- is the air filter element intact?
- is the air filter box and and cold air intake free of squirrel nesting activity?
- is the MAF entry screen free of debris?
- are the MAF sensor's element wires bright shiney and new looking clean?
- are the throttle switches serviceable?

If they haven't been done, all the original little fabric-covered vacuum hoses need to be replaced with better to properly deliver vacuum. Follow the under-hood diagram and do a thorough survey to find them all.

See also the vacuum connection hose and tubing for the FPR; and the engine grounds mentioned in "Limp-Home" Mode at 20v.org.

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