Hafner

Hello all, apologies for the long introductory post, but there is a question buried down below.

I recently purchased a gunmetal gray 1986 Audi Coupe GT with 110K milesfor roughly $2,000; it's somewhere in between a beater jalopy and an impressively clean original car. For example, the paint looks impressive from 20 feet away, but when you get closer you can see the clearcoat peeling in places. The parts all appear all original, which isn't necessarily a great thing if they should have been replaced. And the previous seller was a 21-year-old hot-rodder who had no maintenance records.

Anyway, I have always loved these cars and am eager to restore this CGT to its original running condition. Unfortunately, I have little to no mechanical chops of my own and so am mostly acquainted with writing checks to get things done on cars. I am trying to change that, and I'm trying to learn how to do this myself with the help of the Haynes manual, a lot of Google searches, and hopefully with any advice you guys see fit to help me with.

Anyway, on to the issue at hand. I hired a local shop to get the car up to basic spec - change oil, change brake fluid, change tranny fluid, repair an exhaust leak at the manifold, that sort of thing. Then the car failed emissions; cruise emissions were okay, but idle emissions were pretty horrible, failing both CO and HC.

I'm suspecting one of two things, possibly both. For one thing, the distributor cap, rotor, and spark plugs all look old, possibly even original(!). It's definitely possible that we're getting incomplete combustion, and so redoing cap/rotor/plugs/air filter might help give the engine the raw materials it needs to get a good spark and better combustion. It's a measure of how raw I am under the hood that I was super excited when I replaced cap/rotor today and everything worked. Tomorrow comes the plugs, plug wires, and air filter, and hopefully that will help.

For another, the idle can be pretty unstable depending on conditions - when I start the car, it almost stalls a few times before recovering, when I declutch coming to a stop, it almost stalls, and when the cooling fan kicks on the idle drops to almost stall to normal, then back to almost stall, etc. It was doing this when they were measuring the idle emissions, and I'm guessing the see-sawing probably didn't help my case.

So, my question is this - I've found a few links across the web that say this idle issue is pretty common on these cars, and that one of two things will help:
- This gent argues that unscrewing the idle screw, cleaning it off, and spraying a bunch of carb cleaner in while the engine is running will clear things out.
http://www.carbibles.com/coupegt_tips.html
- I've seen many other places that the ICV can cause problems if it's dirty - that disconnecting it and liberally flushing it with carb cleaner can help.

Of course, the placard on the bottom of the hood and the Haynes manual strongly discourage messing with this stuff. What do you guys think? Should I go ahead and start messing with the idle screw and ICV? Is there any harm to doing so?

Any help would be appreciated. Future questions from me will probably cover these topics - don't worry about answering this stuff now, it's just a preview:
- Does anybody have a good source for a sunroof crank?
- Are there two fuse box locations? I found mine under the hood near where the windshield washer fluid heads up to the hood, but Haynes says there's one behind the glove box ...
- Are cigarette lighter failures common? I *believe* the fuse checks out fine ...
- I get a couple of minutes worth of ticking noise when starting cold in the morning - likely hydraulic lifters. Is that common? Should I be worried?
- Does anybody know of a good independent VW/Audi shop in the Seattle area I could use when I get over my head? The dealer and the all-makes independent shop I normally use seem flummoxed by the CGT.

Hafner

In case anyone's curious, here are pictures of my new CGT - isn't it pretty?

Hafner

In case anyone's curious, here are pictures of my new CGT - isn't it pretty?

Sigh ... not so pretty when you can't see the photos.

I created an AudiWorld Forum Gallery instead. Pics are here:
https://www.audiworld.com/forums/alb...albumid=161142

1986audi

Looks like a very nice coupe GT. The condition is very good considering most I have come across. I think the leather interior is fairly rare in the later cars as well. Good luck with it.

ScottRB

Is a pain in the butt to get to.
Have fun.
Very nice looking.

Blewtoon

Nice looking car.
Be careful when doing the airfilter that you get all the vaccume hoses connected & tight Vacccume leaks are one of the most common problems with these cars. Yes clean the ICV while changing the filter. Spray carb cleaner through it & click it open & shut with a 12v jumperwire. A sticky valve will cause surgeing at idle. The lifter noise at startup is common. try using 20/50 oil & a Mahle or Mann oilfilter at the next oil change.
There's a good chance that you are gonna need a new O2 sensor. to get passed emisions but a full tune up (Plugs,wires,rotor,cap,& airfilter)first should help

4corners

In many cases it is easier and quicker to gain access to the air filter by simply removing the headlight, remove filter box clips and then tilt it up and pull the old filter out sliding it towards the front then reverse the procedure for the installation. This way you avoid damage to the intake boot and associated vacuum hoses.

Hafner

Good news - my mechanic tweaked the CO mixture and the car passed emissions with flying colors.

The new distributor cap/rotor, air filter, and spark plugs & wires have made a difference too, it sounds more like a car than a truck now!

Now, on to the next few projects - I'll put up new topics for those as I go.

Thanks for the welcome and the help!