I recently made another post about my issues with lack of fuel pressure. When I hook up a fuel pressure gauge to the fuel rail and KOEO I hear the pump prime and the fuel pressure jumps to about 43 and immediately drops to about 21 then bleeds off to zero. I would like to test my regulator by pinching the return hose, but it is not immediately obvious to me where it is located. Does anyone have any clues?

 

you can tell the return line bye the size of the hardline on the frame it is the smaller 5/16 tube.

 

The regulator is on the fuel rail. Pull off the vacuum hose to it & watch for gas to come out.

 

The fuel rail holding pressure after the fuel pump shuts off was barely reliable when these things were new. There is a check-valve in the factory fuel pump system that's supposed to prevent back-flow through it. After tens of thousands of miles (and decades of time) they just can't be relied on to work perfectly any more. Fuel pressure will bleed down after the fuel pump shuts off. Some will do it quickly, some slowly, but they all leak back.

Bad regulator, leaky injectors..... sure, anything is possible in those areas as well. If it runs OK, it's probably not injector problems. The regulator could have a ruptured diaphragm (do ex-x-fire's check, above for that issue) or it could just be leaking past the regulator valve itself.

The question really is..... does it hold fuel pressure if the engine is running and does the engine run well at idle? If so, the problem is likely a minor one (small-leak back at the FP or regulator) not worth getting too twisted up over.

 

Hey guys thanks alot for those responses. I would have thanked you sooner but I have been so busy latley, Military keeps us busy. Ill go ahead and these things, unfortunatly a few other problems have popped up with the vehicle but its a 26 year old car and I guess that is to be expected.