Fuel Pressure Test hookup..

[rothsean]

My friend will let me borrow his fuel pressure digital guage. Where do I hook it up? I really want to check fuel pressure after shutdown to make sure that my new accumulator is holding pressure.

How long should the accumulator hold pressure for? What should the pressure be while running and while shut down?

Thanks!!

[WelmoedJ]

My friend will let me borrow his fuel pressure digital guage. Where do I hook it up? I really want to check fuel pressure after shutdown to make sure that my new accumulator is holding pressure.

How long should the accumulator hold pressure for? What should the pressure be while running and while shut down?

Thanks!!

There are a lot of threads in this regards.
Just do a search for fuel system (pressure), rest pressure etc.
You'll find all you want to know.

[David T]

If you are going to be doing this kind of stuff it is really important you have (and use) the Workshop Manual. This is all explained in there.
David Teitelbaum

[Bitsyncmaster]

The workshop manual says to have 15 min of rest pressure but that only proves you don't have a masive leak. I have found holding less than 4 hours can give me a warm start problem in hot summer days.

[82DMC12]

Dave (Bitsyncmaster) has a fantastic solid state rpm relay that will do a couple of things to help maintain rest pressure as long as everything else is working ok.

My car had no problems as per the specs go but I still had a problem with hard semi-warm starts. Dave's relay cured all my ills and I can't say enough good things about it!

Andy

[David T]

If the TTS is not working right and won't fire the CSV on a warm motor you will also have difficulty starting. There is a period when the motor is too warm to start on the CSV but you don't have enough rest pressure to have fuel coming out of the injectors. The CSV will operate without rest pressure but the injectors won't. You could also have a CPR a little out of spec. Between that and a TTS that is out of spec you have a hard warm start.
David Teitelbaum

[Bitsyncmaster]

If the TTS is not working right and won't fire the CSV on a warm motor you will also have difficulty starting. There is a period when the motor is too warm to start on the CSV but you don't have enough rest pressure to have fuel coming out of the injectors. The CSV will operate without rest pressure but the injectors won't. You could also have a CPR a little out of spec. Between that and a TTS that is out of spec you have a hard warm start.
David Teitelbaum

The CSV only works when the engine temp is below 95 deg/F. So how long do I have to wait on those 100 degree days after drive somewhere?

[David T]

Probably till nightfall! You probably have leaky injectors causing you to not hold rest pressure long enough. The book says 1.7 bar after 10 minutes. I have seen cars that hold rest pressure for hours and some that only hold it for 10 minutes. Obviously the longer the better, the quicker the motor will start. The "improved" RPM relay will help by getting system pressure up faster so the injectors can work sooner.
David Teitelbaum