Audi200T5000S

I have just recently replaced on my '89 200 Turbo the fuel pump, starter, fuel pump relay. The car starts when cold. After it has warmed up the car will not start. It also does not want to idle well. At times if I have to slow for stop sign or traffic light and remove foot from gas the car will quit. Then when I try to restart, it will not start until it has cooled down. Thought the problem may be the fuel relay. Replaced it yesterday, not it. Any help greatly appreciated.

elToro

1) Hot start problem: might be temp sensor. The car doesn't know how hot the engine is so defaults to cold start mode which is too rich. Does your exhaust seem rich?

2) Bad idle/stall problem: probably a vacuum leak (check your breather hoses).

86_5K

Hold the gas pedal all the way down, see if you can start the car.

Zhaoming

SteveAngry

since you just replaced your fuel pump.

New fuel pumps come with a check valve already mounted...

I'd check crank postition reference sensor or fuel injectors...

Maybe a clogged fuel filter that swells with the heat?

Steve
Michigan

Adam Mowafy

would'nt a bad check valve cuase: poor starting regardless of temp. becuase fuel pressure would leak back into the tank and then youd get your hard starting. the engine might still be warm when this happens or it might be cold. I dunno I could be off on this one.

heres a test for the check valve: turn the key to the on position(not start) then turn it off, then on, this will give the fuel pump a chance to build pressure since it comes on for a few seconds when the key is in the on position. then try to start it.

I have a bad check valve and I get poor starts cold or hot. usually after about 20 minutes of sitting thats when the fuel pressure starts to go away. I dont think it's injectors or seals because it would take longer than 20 mins. to leak out of an injector (I think...)

Adam Mowafy

Damn, I forgot you said you recently raplaced the fuel pump, oh well Just more typing practice

audiqv8

Pull the DTC code when it doesn't start. Crank the engine for approx. 15 seconds and leave the ignition on, then pull the codes.

If it isn't the fuel check valve, then my guess would be crank position sensor (quite common for Quattro V8 engines, because they are located so close to the exhaust manifold). Heat kills these sensors.