Audi 90 stalls in park or neutral
 

My Audi 90 (1994) 2.8 liter automatic, stalls in park or neutral. Seems to idle well when not in those two. If I start it it idles in park for about min and then turns off. If I drive somewhere, anywhere, it shuts off a second after I put it in park or neutral.

I read about stall problems here and other places on the net and I have a few ideas about what it might be (ie idle control, fuel injectors, others that I forgot), but no ones problem or symptoms is/are exactly the same as mine. So I'm here begging for help [sm=hail.gif]

RE: Audi 90 stalls in park or neutral
 

What happens if you try to give it more gas in either park or neutral does it respond or die?

RE: Audi 90 stalls in park or neutral
 

I tried it today, and it keeps running if you give it gas. But if you get off gas it stalls.

RE: Audi 90 stalls in park or neutral
 

You may need to clean or replace the idle air valve.

RE: Audi 90 stalls in park or neutral
 

Idle air valve and the throttle micro switch is a good start. However I find it kind of odd that you can idle in gear but not in neutral or park. Usually it is the other way around. How long have you had this problem? Was it something that just happened all of a sudden or was it more gradual? Do you have the "check engine" light? If not, does the bulb light up with the ignition in the on position, sometimes the bulb is deliberately pulled out or burned out. I would also check the timing and look for vacuum leaks especially between the mass air flow sensor and throttle body.

RE: Audi 90 stalls in park or neutral
 

I cleaned the ISV with half a bottle of WD-40. But I'm not sure I did it right. I just sprayed it in and rinsed it out, a few dozen times.

I left the car idling on in wet snowy weather. And it stopped idling. And then I've been having the problem ever since then. So it was not gradual. I don't no what micro switch is.

The check engine light comes on when ignition is in on position. But not when car is running.

I will check for vacuum leak between the the mass airflow sensor (don't know what that is) and the throttle body (got little better idea what that is). I fixed a vacuum leak between the value cover and air intake tube near the manifold, so it's possilbe i got another one.

RE: Audi 90 stalls in park or neutral
 

Jimmy

When did you clean the ISV before the problem started or after?

Never use WD-40 to clean the ISV. WD-40 is designed to evaporate and leave a sticky residue for lubrication. It is actually quite thick and gummy when all the solvents evaporate. I use brake cleaner or carb & choke cleaner. Generally what I do is plug one end and spray some cleaner inside, plug the other hole and shake it back and forth for a few seconds, drain and repeat a few times until the cleaner comes out clear. A word of caution be very careful that the plug doesn't pop out or when removing it as there is tendency for some pressure to build up from the cleaning agent. Carb & choke cleaner really works great but is more aggressive towards some plastics, brake clean works well on mild deposits and I recommend it first. Never leave the cleaner for a long time and don't use any brushes, cotton or paper towels, etc to wipe or scrape the inside. The tolerances are very close and even one piece of lint can cause the valve to stick. I use compressed air to blow out any remaining cleaner.

I think that this is probably, as one famous individual now in jail says, "that’s a good thing!" If you have a vacuum leak I am almost certain that the check engine light would come on and drivability would suffer. It still doesn’t hurt to check for any air leaks. Mass airflow is usually located on the air filter box and has an electrical connector.

The micro switches are located on the throttle body and are not always accessible or visible, but there should be a connector. When the throttle is closed this switch tells the computer to open the ISV and start controlling the idle speed. There is also a throttle position sensor. Which connector(s) is where I don’t know but I would check them as they have tendency to wear out, break, or corrode. The switches could be checked for electrical functioning with a digital volt ohmmeter (DVM) but you will need a wiring diagram to know which one to check.