skystrick

1986 Coupe GT. 2.2L manual trans.

Fuel injection has been acting up for the last week. Motor idles high. Normal idle for this car is ~800-900, but been doing anywhere from ~1500 to ~2500 at stop lights the past week. Sometimes it does it, sometimes it doesn't. Also intermittently surging while driving (i.e. cruising with steady throttle, car suddenly gets more power.) Can't find a pattern.

Now it won't start. Hold the key and the engine just keeps turning over without firing. If I do it long enough, I can smell unburnt gas. If I slack off a few minutes and try again, it will cough/fire one time the second I hit the key, but then go right back to cranking with no ignition.

Rogviler

The #1 thing on these is vacuum leaks. You HAVE to use smoke to find them, the dinky "spray carb cleaner trick" is useless (especially if the car doesn't start), probably because there's so much vacuum stuff buried under other stuff.

Use a machine or just blow smoke into a vacuum line. Look for where the smoke is coming out.

Once you've found and fixed any leaks you can move on to the next thing.

-Rog

AudiCoupeGT1986

Would be worth checking the O2 sensor and the related wiring as well. A failed O2 sensor could cause running issues. Wouldn't hurt replacing the fuel filter.

skystrick

So a vaccum leak would cause my car to not run?

I'm assuming it can't be something ridiculous like a vaccum leak to the cruise control?

What part of the ignition and/or fuel injection system runs off of vaccum?

skystrick

For the record:

1) This is my only vehicle

2) I have no tools beyond a couple of screwdrivers and a pair of pliers

3) I can't afford a tow and shop repairs

4) No one works on Audis within 40 miles of where I live in MiddleOfNowheresVille, North Carolina

5) I can take a bus to Wal-Mart. There are no auto parts stores I can get to.


I plan to try spraying some starting fluid later. It's the only thing I haven't tried. Flooding rules out fuel filter problem.

Something is telling this CIS system to dump way too much fuel into the cylinders.

AudiCoupeGT1986

Check the Cold Start Valve. Make sure it's not staying open when the car fires up. It shouldn't open when the car is already warm either. Again, check your O2 Sensor. Make sure it works.

If you plan on owning a car this old, it would be smart to own some tools. It's almost a 30 year old car. Seriously should consider getting another car as a daily driver while you attempt to get this car going. It will break...

AudiCoupeGT1986

I highly doubt that. I would check out Quattroworld.com and ask around on the 4000/CGT forum there. There are definitely people in NC who could help you.

Rogviler

Oh yes. I tested it once and a 1/4" hole can cause the car not to run at all. So think of a small crack or two somewhere you can't see...

The fuel injection system itself, really. Since how much air is going past the metering plate dictates how much fuel goes into the engine, a vacuum leak anywhere can cause a big problem. Common places are the air boot itself, especially in the folds and underneath, and braided lines (I've seen smoke come out of the pores during testing). You can also get leaks around the injectors.

At any rate, that's an easy and cheap thing to test and fix, and if there is a leak, nothing else will make it any better.

-Rog