20 Most Recent 1991 Audi 100 Questions & Answers

It automatically opens and adjusts the amount of air into the intake to control idle when the throttle valves are closed (foot peddle not pushed). Older carbureted cars used a set screw to hold the throttle valve open a little to let air in, but your Audi throttle valves close tight when you take your foot off the throttle. If the air idle control valve is not working and sticks in the closed position the engine will not idle unless you step on the gas peddle a little. I cleaned mine up by removing it from the engine and spraying carburetor cleaner through the ports until it was clean.

best idea is to go to a battery shop and have them replace the battery 1---you will get a right replacement battery 2-- they will or should use a supply battery plugged into the electronics so that all codes and programs are not lost

You seem to have a stuck linkage problem. Lubricate linkages to the gas pedal with WD 40 or CRC spray.

check the carb or air intake body if its injection where the breather pipes connect to it .sometimes the metal pipe where the rubber breather fits on to gets carbon inside it .all you need is a thin wire to poke through it .this should clear it out and may solve your problem.

When you say wont accelerate does the RPM flares that would be the transmission slipping, or you step on the pedal all the way and the vehicle has lack of acceration you can hear a hissing noise that would be a plugged exhaust.Here the thing you related it to fuel has the problem on the ignition coil is a powerstage if this stage acts up it allows you to accelerate you just dont go anywhere it back fire through the intake that would be the power stage it located on the ignition coil

There are many possible causes of an engine stallng, however, The most likely cause of the symptoms you are describing would be a defective Idle Air Control Solenoid. (IAC).
It is located on the intake plenum near the throttle body and it looks like the picture below.

The first thing you must do is have the electronic engine control scanned for fault codes, otherwise you have no place to start from

Is your check engine light on? Have your run a scan to check for fault codes? The symptoms that you describe can be caused by more than one problem. There are various sensors on the fuel and ignition systems that could be faulty.

Not good! If your sure it not a hose leaking, you could buy some raidiator stop leak product at the auto parts store. The stop leak product will stop up your heater core so you won't have much heat in the winter, but it will probably stop your water pump leak if it's not a big one. I'd say replace the water pump and stay warm, unless you're not going to keep the vehicle much longer.

its so old this car a i cannot remember correctly ,havent seen one of this model for at least 5 yrs ,anyway if i remember rightly the door panel comes off first then the wooden trim ,its held on with 2 nuts 10mm heads

can it go from 1st 2nd 3rd then drive? if so it can be a transmission shift control module

you need to reset the immobiliser,if you havnt got a book get back soon......

follow your fuel line from the fuel filter and it will lead you to a pressure regulater and than to the injecters.

Please see my tip at http://www.fixya.com/cars/r5833579-auto_truck_c_recharge and let me know if you have questions.

under the back seat

either crank sensor or ignition module

Replace the caliper.td

You may have a ground that has lost connection,check all your grounds near the front of the vehicle.They will be grounded to the body make sure they are clean and free of rust.