V8 Fuel Pressure Regulator symptoms?

[Foxspell]

Good morning all,
I have a '97 D1 V8, going through a process of elimination, what are the symptoms if your Fuel Pressure Regulator has failed.

As always, your help will be greatly appreciated.

Lee

[bee utey]

Two common failures of fuel pressure regulators are

1. Failure to hold the desired pressure, put a suitable pressure gauge on the rail and note the reading at idle, on sharp acceleration (should be about 10 psi higher) and how long it holds pressure after switch off.

2. Failure of the diaphragm inside, petrol bypassing the diaphragm will enter the inlet manifold and make it run super rich.

Also the vacuum hose to it can go soft and fall off its vacuum nipple on the back of the manifold, also causing rich running.

[steelo]

Could that be causing the surge I get when left in "D" at a set of lights, but when I put it into "N or P" or put aircon on it stops??? :confused: Oh & the 1st start-up of the day can most times be a pain in the but, I have to hold pedal down all the way & just continually turn motor over till it kicks, & get a huge flooded petrol smell. Funnily enough if it's sat for a couple of days it starts straight up 1st click.
Thanks :)

[Roverlord off road spares]

Have you checked the small rubber hose that connects to the FPR, it goes to a small nipple on the plate at the rear of the plennum. If you look at the IAC (Stepper motor) on the rear of engine drivers side, and feel with your fingers you'll feel it. This hose is small and can fall off or break. It controls the vacuum on the FPR.