eventoday

Hi everyone.
I have a 1990 Audi 200 quattro wagon. 220k miles.
It runs really great until...

The other day I drove about a half hour away. When I went to leave I turned the key and the car stumbled and stalled. I Tried to restart and it would not start. I tried to start for an hour and it would not. It cranked and sounded like it normally does but wouldn't turn over.

Towed to my mechanic

Go figure a few hours later when he tried it , it fired up and started. They couldn't find a problem. They put a new distributer cap on.
I drove for a few days with no problem till today. Drove it on freeway for half hour. Got home . 10 min later I went to go back out . I turned key and it started, stumbled and stalled. It would not start back up.
Few hours later started with no problem

Any advice or thoughts? Don't want to drive it and get stuck

yodasfro

Possibly a failing hall sensor in the distributor. That or it could be fuel related? Need to check for fuel and spark when it won't start. Also check the fault codes. Don't rule out regular maintenance/tune-up stuff too fuel filter could be getting clogged plugs/plug wires could need changing. Also it could be that the fuel injectors are leaking after shut down.

eventoday

Thanks for the reply. Is there an easy way to check for spark with no special tools? Could I take the wire to the rotor off and see if it Sparks? ( is that a bad dangerous idea) What about to check fuel?
Sorry to ask these are probably basic questions. I'm good at following directions but have no experience in diagnosing issues.
I get the feeling it will not reproduce at the mechanic shop.

yodasfro

To check for spark take a wire off a spark plug and insert a spare spare plug
(or remove one to use) and rest it on the valve cover so it makes some contact. Have someone turn the key while you watch for it sparking. Safer way is to buy an inline spark tester that has a light bulb that will light up. Checking for fuel listen for the fuel pump priming while cranking. You could also remove a spark plug and see if it's getting wet with fuel.

eventoday

Thanks so much again.
Next time it won't start I will try those tests.
Just another quick note I remembered.
Both times it happened I filled up on gas prior.
Also
I've noticed a hum in the back of the car when it is on and I'm driving. I found out that is where the fuel pump is. Any correlation do you think?

yodasfro

Yes and no the fuel pumps are known to make noise nothing really to worry about. It's when it stops making noise then it's a problem = dead fuel pump
Fuel filter is worth changing if you don't know when it was done last.

Kneale Brownson

A failing engine speed sensor (counts the teeth on the flywheel ring) or ignition reference sensor can prevent hot/warm restarts. They're mounted on the driver side of the engine where the bell housing connects to the engine. Sometimes a bath of cold water will permit a restart. You also can test their soundness following the procedure in the Bentley.

eventoday

Thanks Kneale,

Is that the same thing as the hall sensor? Or are the different?
If different are they cheaper than the Halls sensor? Maybe I should try it first?

My mechanic mentioned to mee when it wouldnt start again he was suspecting the Hall sensor. The only reason he didnt replace the first time is because he said something about the dis cap was sparking kind of crazy and wanted to try the cheaper route for me first.

Im taking back to him tomorrow. He generally works on Volkswagen Vanagons but has worked in a few of these in the past. Ive been asking lots of questions and reading to give him any insight I could find out. He probably knows everything I have been told but I like to learn myself too.
Once I move out of my condo and back into a place with a garage I will work on it myself.


Im going to take the car for a 45 minute drive today and end up back at home and see if I can reproduce the no start

THanks

yodasfro

In my experience the crank sensors don't tend to fail on the turbo cars like they do on the V8Q. But next time it happens try some cold water on them like Kneale said.

eventoday

Hi Again,
Just an Update.
I was able to reproduce the no start today. I drove it for about 45 minutes. Drove terrific. Mixed freeway and stop and go.

Got home as soon as I shut it down it did start right back up. I waiited 10-15 min went back out. It started but idled rough. I shut it down. I immediately tried to start it again and it would not fire back up. It just cranked.
I noticed this time none of my tach items were moving except battery volt. I read somewhere to check and see if tach was moving.

I tried cool water on the engine speed sensor. Still would not start. went back out 20 min later. still no start.
So I am waiting (at home) and expecting it to start up for me in 2 hours.