Fuel pressure leak

[Germanator]

I am trying to find a fuel pressure leak.
I already know it is not the fuel pump, it can only be a fuel injector, or the fuel pressure regulator (according to the Bentley manual).
Does anybody have some advice on what is the best way to find out what's the culprit?

Any input, suggestions or advice?
Cheers
Jurgen

[ossiblue]

Originally Posted by Germanator

I am trying to find a fuel pressure leak.
I already know it is not the fuel pump, it can only be a fuel injector, or the fuel pressure regulator (according to the Bentley manual).
Does anybody have some advice on what is the best way to find out what's the culprit?

Any input, suggestions or advice?
Cheers
Jurgen

We need much more information, beginning with the year and model of your car.

You need to let us know how you concluded you have a fuel pressure leak. Tell us what tests you have run and what were the results. Tell us how you concluded it can only be an injector or the pressure regulator.

Please share with us your diagnostic process so we can understand how you reached your conclusions.

[Germanator]

Sorry, my mistake.
It is a 1988 911 and I performed the Bentey fuel pressure test. Connecting a fuel pressure gauge at the fuel rail. When achieving operation pressure running only the fuel pump I shut the pump off and the pressure quickly drops. Normally it should be 15 min or so before the pressure should be low. In my case it was minutes.
I repeated the test with clipping the return line off which according to the Bentley manual indicates it is the fuel regulator or fuel injectors.
I also noticed my fuel pressure was a bit high can 40 PSI and the manual says 36 not sure if this matters.
The
J

[ossiblue]

Originally Posted by Germanator

Sorry, my mistake.
It is a 1988 911 and I performed the Bentey fuel pressure test. Connecting a fuel pressure gauge at the fuel rail. When achieving operation pressure running only the fuel pump I shut the pump off and the pressure quickly drops. Normally it should be 15 min or so before the pressure should be low. In my case it was minutes.
I repeated the test with clipping the return line off which according to the Bentley manual indicates it is the fuel regulator or fuel injectors.
I also noticed my fuel pressure was a bit high can 40 PSI and the manual says 36 not sure if this matters.
The
J

The above helps a great deal. We now know you have a car with EFI and not CIS which make a huge difference in diagnoses and solutions. Since I have no experience with EFI engines, I will let others chime in and offer suggestions. No doubt, it will be very soon. Good luck.

[bazar01]

If you clamped just the fpr return, and it lost fuel pressure, you have 3 suspects, injector stuck open, fpr bleeds or the check valve is stuck open.

Clamp the fuel rail pressure line too. If it holds pressure, then the check valve is the culprit.

[Germanator]

Thanks for the feedback, I will try this. Which of the hoses is the fuel rail pressure line?

The real problem that I am trying to solve is the warm starting issue I have a for a while now.