quick fuel prossure drop when off

[z1huggy]

I've got a adjustable fuel pressure regulator and as soon as the engine is off the pressure drops to 0. HOw long should it take for the AFPR to bleed down? If the AFPR has a vacuum leak inside would it in turn have a hard time raising the fuel pressure under boost? Could enough vacuum leak out to cause drivability issues too?

 

[gnturbo]

been wondering the same thing lately,one way of finding out if you have fuel pressure at wot is to have an extension off your fuel rail monted gauge and hang it out of the top of the hood when you are driving and see for yourself thats what I am about to do.I have a problem with my fp dropping once the car has warmed up

 

[Ormand]

Three possibilities

When you shut the engine off, the fuel is trapped in the fuel rail. It can get out by 1) leaking past the AFPR, 2)leaking into the engine through one or more injectors, or 3) leaking backward through the pump check valve to the fuel tank. You can check it by using a pair of clamp-on pliers. Use the pliers to squeeze the rubber return line closed at the front of the engine, between the AFPR and the tank. Turn switch on, then off. The pump should pressurize the line. If pressure goes up, stays up, the AFPR is the problem. If not, try again. This time, turn on switch to start fuel pump, or use a jumper to the fuel pump connector behind the alternator. REAL QUICK (need someone to help you if you use the switch) close off the rubber line from pump to the fuel rail. This will eliminate the path back to the tank. If pressure drops off, it must be the injectors.
All this stuff is on the GnTType web site, I think.

 

[Crazi]

Here is what my problem was. The feed line had been rubbing on the floor pan of the car for long enough to wear it thin. I started smelling gas about a week before I couldnt take it any longer and crawled under the car. Actually, my fp started dropping fast at cut off so I knew there was a problem. Anyway, the rubbed through part was really close to the end where the rubber line is at the tank so I just cut the messed up part off and connected the rubber line to the good remaining hard line.

Moral of the story... Do you smell gas at all???