Fuel pump or filter issue?

[morris400]

Car is a 94 s4, in the morning or after it sits for even just a hour it takes forever to start. I will turn the key and it will crank but not fire up, then I turn key to acc, then try again and 99% of the time she will start right away.

If I park the car on a down hill slope (hood down trunk up) she will 90% of the time just fire up first key turn but if I park on flat ground or up hill slope then I have the above problem.

What do you guys think it can be? Pump filter ect ?

Thanks guys

[morris400]

Re: Fuel pump or filter issue?

Well I changed the fuel filter today, when I pulled the FP fuse the car died right away, swapped the filter and the car started after a few cranks, then resized I installed the washer on the wrong side of the banjo bolt. So I pulled the fuse again to fix this problem and this time with the new filter it took almost a min for the car to stop running. Is this a good sign?

I also changed the oil and got rid of the k&n air filter and replaced with a Mann.

[jta430]

Re: Fuel pump or filter issue?

Car is a 94 s4, in the morning or after it sits for even just a hour it takes forever to start. I will turn the key and it will crank but not fire up, then I turn key to acc, then try again and 99% of the time she will start right away.

If I park the car on a down hill slope (hood down trunk up) she will 90% of the time just fire up first key turn but if I park on flat ground or up hill slope then I have the above problem.

What do you guys think it can be? Pump filter ect ?

Thanks guys

there is no one way valve in our cars so if the car sits for a while the fuel can drain out of the lines, and take a few cranks to get the fuel back to the injectors.

[morris400]

Re: Fuel pump or filter issue?

there is no one way valve in our cars so if the car sits for a while the fuel can drain out of the lines, and take a few cranks to get the fuel back to the injectors.

That I understand but in the mornings it takes almost 20-30 seconds....is that normal?

[PRY4SNO]

Re: Fuel pump or filter issue?

That I understand but in the mornings it takes almost 20-30 seconds....is that normal?

No.

[morris400]

Re: Fuel pump or filter issue?

ive ruled out fuel pump cause it works. fuel filter is still in the air. next is fuel lines under the car

[morris400]

Re: Fuel pump or filter issue?

ok so this morning the car was facing dwn hill and started fine. drove to work (50k) and parked. car sat for a hour and a half and when i went to start it it took forever again. im guessing im looking at clogged fuel lines maybe?

[BaggedGLI]

Re: Fuel pump or filter issue?

Maybe run a bottle of fuel system/injector cleaner through?

[morris400]

Re: Fuel pump or filter issue?

ive ran some seafoam through the fuel system a few times with no change.

[onceover]

Re: Fuel pump or filter issue?

I would think that it's losing fuel pressure somewhere if you can prime the pump a few times and have it fire right away

[EXP]

Re: Fuel pump or filter issue?

It sounds like the check valve, its a banjo type bolt that fastens the fuel line at the fuel pump inside the fuel tank.
my rule of thumb, engine is warm and has been run for a while,has been shut off for a period of time, long crank starts and stumbles -injectors,leaking and flood cylinders
same as above, long crank and starts and runs normally, check valve, it bleeds off pressures and draws air into the fuel line.

[morris400]

Re: Fuel pump or filter issue?

It sounds like the check valve, its a banjo type bolt that fastens the fuel line at the fuel pump inside the fuel tank.
my rule of thumb, engine is warm and has been run for a while,has been shut off for a period of time, long crank starts and stumbles -injectors,leaking and flood cylinders
same as above, long crank and starts and runs normally, check valve, it bleeds off pressures and draws air into the fuel line.

From what I've been told there is no check valve in the fuel lines.

[EXP]

Re: Fuel pump or filter issue?

I know your asking a question, you are also getting conflicting answers but Riddle me this then.....how does the fuel system stay pressurized after it has run and than shut off. As the engine is now warm or hot it will not need as much fuel to start so the cold system function does not operate to start the car which gives more fuel, you also have little pressure after it sits and cools off, ie a fuel pressure test and should hold for a certain length of time
When you do a hot start engine demands very little fuel therefore the system needs to be pressurized to be able to deliver the fuel instantly
you may not be able to get a check valve separately, maybe comes built into a pump.
You might have to just call and ask for one and see how it comes
Hopefully this helps you out.
Good luck

[morris400]

Re: Fuel pump or filter issue?

im looking into some more ideas, thank you EXP, i will be looking to see if there is a check valve in the fuel pump. i am also looking into changing fuel injector seals and cleaning uot my injectors.

[toplessvw]

Re: Fuel pump or filter issue?

you seem to be having a fuel pressure bleed down issue, the fuel pump check valve, fuel pressure regulator, or injectors could be at fault. I would have to guess the pump has an internal check valve. So I would recommend getting a gauge on there and checking the residual pressure drop. Should not be more then 0.5 bar over a half hour.
Do you have any black smoke at start up when it sits? You could have your injectors bubble tested to see if they are leaking.