trouble starting when engine is hot
#1
trouble starting when engine is hot
Can anyone give me a clue as to why when my engine is hot it gives me alot of trouble starting? It cranks over fine but, it won't "catch." After a minute of cranking it will usually start and generally run real crappy and blow out black smoke. Today I tried to start the car when it was already hot and it wouldn't start. Finally with the gas pedal all the way down it started, and blew out alot of smoke. Then I had alot of trouble keeping it running on the way home. The car starts and runs great when cold though. This is a 92' Audi 100 with the 2.8 V6. Any input is greatly appreciated! Thanks alot,
-Matt
-Matt
#2
RE: trouble starting when engine is hot
its look like its too reach, I would check the fuel pressure, and if it doesn't help I would disconnect one by one the injector.
example disconnect the first cyl injector and try to start, then conect it back and try the second then therd etc...
and therir is definatly more that I said.
example disconnect the first cyl injector and try to start, then conect it back and try the second then therd etc...
and therir is definatly more that I said.
#3
RE: trouble starting when engine is hot
If the car starts and runs OK while hot but refuses to start after a short break. The problem could be inability to hold pressure due to a defective check valve. When the engine is hot and there is no or low pressure in the fuel line, the fuel boils and you get a vapor lock. Perform a residual pressure test.
#4
RE: trouble starting when engine is hot
Offramp, I'm guessing you mean to check the fuel pressure when the engine is hot?
P.S. Sometimes the car will start up and run perfectly when hot. This is not a consistent issue. Does it still sound like a check valve to you?
P.S. Sometimes the car will start up and run perfectly when hot. This is not a consistent issue. Does it still sound like a check valve to you?
#5
RE: trouble starting when engine is hot
That's the idea. There should be a procedure in the manual on how and where to hook up the pressure gauge. Then you follow a chart, I think it should be fuel pressure vs. time. Warm up the engine, shut it off, then watch the gauge, I think you should have at least %50 of pressure after 30 minutes.
#6
RE: trouble starting when engine is hot
Haha that's just my luck, I've looked all over for a manual on my car and finally had to order one... It'll be in, in about 2 weeks! Anything I can do before that? Does anyone know if this is a return or return-less style fuel system? Could I try turning the key on and off priming the fuel pump over and over again and filling the line with fuel?
#7
RE: trouble starting when engine is hot
P.S. Sometimes the car will start up and run perfectly when hot. This is not a consistent issue. Does it still sound like a check valve to you?
All modern fuel injection systems have a return line. I don't think that turning the key on and off will help. This is due to the fact that injectors don’t have a return line.
It is also very likely that you might have an electrical problem. When the car fails to start try pulling a trouble code of the ECU.
#8
RE: trouble starting when engine is hot
I just want to understand this alittle better. One possibility is that my fuel line is losing pressure, and making it difficult to start. Why does it start right up in the mourning when there's no fuel in the line? Does the car have a different procedure for starting when the engine is cold?