Audio 80 1994 iddle problem

Vegeta

Hi all,

I was wondering what could be causing a 1994 audi 80 1.6 petrol to iddle badly when it is cold in the mornings. It takes several attempts to start it in the morning.

Once the car is warm it runs fine

What is the worst case scenario here?

might it be a sensor, if so how much would it cost to set it right.

Is an Audi main dealer the way to go???

Your help is greatly appreciated

mike65

It could be the cold start valve/injector. You car has Bosch KE injection which uses a fifth injector to enrich the engine on a cold start, if its not working properly you can get the symtons you describe. Do you have to keep your foot on the gas until its got some heat in the engine?

Mike.

Vegeta

mike65 wrote:

It could be the cold start valve/injector. You car has Bosch KE injection which uses a fifth injector to enrich the engine on a cold start, if its not working properly you can get the symtons you describe. Do you have to keep your foot on the gas until its got some heat in the engine?

Mike.

Ok just to fill you in a little more on the issue.

For instance the car took four attempts to start this morning. if the car was warm it starts first time

Once the car is started and running for a while everything is fine bar the low iddle problem. The car iddles at very low revs close to cutting out at times

If the accelerator is pressed while iddle (regardless of being warm or cold) the revs climb uniformly and smoothly but when you take your foot off the accelerator the revs drop very very low the car chugs a bit and then it recovers.

mike65

The low idle can be tweaked manually. There is a warm idle adjustment
which can be changed with a screwdriver but as I'm not familair with your car I don't know where it is. (Its usually to be found under the airbox above the cylinder head).

example

Something else that might need altering is the throttle cable rest postion and the micro-switch if its wrong starting can either be hard or cause crazy high idle (depending on position).

The pic below is from a 1990 Merc using the same basic injection system. If you are'nt familair with your engine systems then it best to leave it to a professional.

http://img.photobucket.com/albums/0903/mike65/micro-switch.jpg

Mike.

Vegeta

mike65 wrote:

The low idle can be tweaked manually. There is a warm idle adjustment
which can be changed with a screwdriver but as I'm not familair with your car I don't know where it is. (Its usually to be found under the airbox above the cylinder head).

example

Something else that might need altering is the throttle cable rest postion and the micro-switch if its wrong starting can either be hard or cause crazy high idle (depending on position).

The pic below is from a 1990 Merc using the same basic injection system. If you are'nt familair with your engine systems then it best to leave it to a professional.

http://img.photobucket.com/albums/0903/mike65/micro-switch.jpg

Mike.

You the man cheers Mike I will give it a shot.

Is it possible it could be a sensor. When the car is moving there is absolutely no sign of a problem. the throttle response is excellent. It revs uniformly with no dips or splutters.

I'd rather not take it to the local Audi garage as the guy is a pirate and would rob me blind.

mike65

It does'nt need to be a franchise dealer, any good indy should be able to diagnose what needs altering/replaceing.

Mike.

Vegeta

mike65 wrote:

It does'nt need to be a franchise dealer, any good indy should be able to diagnose what needs altering/replaceing.

Mike.

well the girlfriends dad is a mechanic but if i can fix it myself i didn't want to bother him with it.

Cheers Mike

I'll let ya know if you were right