Fuel Pressure Regulator Replacement --- Results???

[Wade Nelson]

Who here has replaced a fuel pressure regulator, and what were the beneficial results, if any?

How did you diagnose it as having failed?

What symptoms led you to decide to replace it, if it wasn't by Tee-ing in a gauge?

[CuadroS]

I replaced mine thinking that the fuel flooding problem was generated here due to a fissure at the regulator's diaphragm. Te regulator was really cheap so I decided to take my chances and replace it. The fuel flooding problem continues with no changes.

[Mikes Z car]

Mine was replaced due to fuel overflowing out of both carbs plus I was having a hard time starting the car, I imagine due to flooding. The overflow was not just a drip or two it was a constant flow, scared the heck out of me with visions of an engine fire. Replacing it stopped the overflowing.

[CuadroS]

Well, mine is a 280zx 1982, which is Fuel Injection, counterwise those with carbs, the fuel overflow is still continues.

Can anyone guide me to whats really the problem allocated.

Tks

[Zed Head]

What do you mean by "flodding"? Running very rich? Search for threads about running rich, there are many. Could be the coolant temperature sensor, or a plugged fuel return line. Measure the fuel pressure with a gauge if you can, that will tell you if it's a fuel system problem.

[CuadroS]

Maybe it's just semanthics, flooding I mean by excess fuel in the cylinder in such manner that the spark plug gets wet and won't ignite. Maybe that's a "running rich issue". I installed a permanent fuel pressure gauge between the fuel filter and the injectors rail. When running rich the pressure is normal, then I disconnect the fuel pump and the pressure drops, but the engine runs normally until, after a few minutes, the engine shuts down.

[Classic83owner]

Yea I'm a bit late here but, From what I'm seeing here Zed is on the right track. I would be checking electrical components such as coolant temp sensor, cold start injector, thermotime sensor, etc. Does the fuel system hold pressure when you shut off the car? Sounds a lot like leaking injectors. The only real way to test the pressure regulator is with the car running with a fuel pressure gauge attached. At idle with full vacuum applied it should read about 30 PSI and jump to about 37 when you rev it up or disconnect the vacuum line. Then you need to attach a hand held vacuum pump and test for leaking vacuum. If you don't feel too stupid doing it you can just suck on the vacuum line as hard as you can and block off the hose with your tongue. It should hold on firmly to your tongue for at least 90 seconds without loosing vacuum.