Ok I drive kind of an older model. It's a 92' 100 CS and I've been having some trouble with it starting lately. I took to it an import shop and they claimed it was the fuel pump and replaced it and said it was fine but then the next day I started to have to same problem only where before it wouldn't start at all now it starts after I crank it a few times. It seems like the engine isn't getting any fuel to start it and I dont know what to tell the shop people so if someone could help with a suggestion that would be great! Thanks.

 

It sounds like the shop addressed one of your problems but did not fix all of your troubles. I suggest that you ask them exactly what was wrong with the fuel pump (was there no pressure? High amps? Bad windings?) and tell them that car starts but does not just pop off at the first crank. Extended crank time can be caused by several different things, If you have access to tools I suggest you check fuel pressure (Just to double check) and watch for pressure drop with key off and engine off. I think you should also try to determine if it is fuel trouble or ignition related trouble. If you don't have access to tools or the place to work on your car, you might end up spending less money taking your car to a reputable repair shop for the tough problems and tackling easier stuff (i.e. maintenence like tune up and fuel filter) yourself. Oh, something easy to check, make ABSOLUTELY SURE that you have good power and ground connections at the battery and chassis.

 

IowaTech, summed it rather well. Quite often I hear the same story all the time, if there is a starting or running problem, replace the fuel pump only to find out that it didn't solve the problem. If the pump is putting out the correct volume and pressure it will last a l-o-n-g time. Most pumps are rather well made and robust. The only way to shorten the life is to run it dry or to use poor quality fuel that is full of sediments and water. As for your starting problem, try using a different brand of fuel first and try puling some codes of off the ECU just after a bad start.

 

Might this be a good place to ask if a problem on my '90 100 is related?

Hot or cold, turn the key, it fires, let off the key, it dies. Remove, re-insert the key, turn, it cranks, starts to fire, then spins the engine a few more revs before it catches. Perfect, after that.

Wondering if the check valve atop the fuel pump is the culprit, quickly losing line pressure, but the cold start valve is giving that initial shot of gas to get the "false start"?

I say quickly losing pressure because it can be from night to morning, or stop at a store, get back in in 2 minutes, same thing.

8 dollar item, the check valve, so I have read, and the manual says take the pump out to replace, though it seems it "could" be done with the pump in the car.

Have to see if my mech has the connectors to test the Audi residual pressure, what, some 70 psi in the later cars?

Cheers,

George