low fuel pressure after blown head gasket

If you know the fpr is good and should regulate at a higher pressure; it is either a leak or the fuel pump itself. If you know there is not a leak and the pump is working, some times you can have a problem where the pump is leaking the pressure partially back into the tank instead of the lines and you will only have partial pressure. A clog somewhere (fuel filter, line kink) could also cause it.

Okay thanks, Ill look into that today.

One other thing I thought about; the fuel pumps do not have a constant voltage from the eccs. On the z, the voltage will vary depending on running conditions. Try hooking up a constant power lead to the pump and see if it fixes your problems. Might just be a wire, relay, or connection problem as well.

Thanks, I'll keep you guys posted. I'm going to work on it today when I get home. I also noticed that my temperature stays very low, no where near half way.

Would putting a Turbo head gasket set on a non turbo motor cause this low fuel pressure problem? I think that car stuff sent me the turbo gasket set and the mechanic put it on my na2t car, will causethis problem?

nope, fuel only goes through the lines and injectors. Nothing to do with engine gaskets or internals.

Okay, I did notice that the pressure goes up when I pull out the vacuum hose from the top of the FPR but only up to 21 psi. I'm going to change the fuel filter tomorrow and see if that works, if not ill try wiring the pump directly, thanks for the help.

My bet is on a fuel pump problem.

okay, I'm frustrated, changed the fpr, the fuel pump back to stock, fuel filter, and still no pressure, i also changed the pressure gauge and nothing. It climbs to 20 psi when I take out the vacuum hose from the FPR, what's going on?

Well, the only components controlling pressure are the pump, fpr, filter, and lines. If you tried two pumps and two fpr, odds are you either have a kinked line not allowing the pressure to build or you have debris in the lines/filter from changing the pump/fpr. If you totally kink the rubber line after the gauge, see if the pressure builds up. It should quickly increase. If the pressure does not increase, you have a problem with the pump not building pressure. If it increases, you either don't have enough freeflowing space in your lines/filter to allow it travel through them fast enough to build up pressure or a bad seal on the pump.

check the pressure at the fuel filter inlet. see if it even gets up passed 20 to begin with. Then check the pressure on the return.

I'll check those tomorrow, thanks for the suggestions

Kinked both lines and pressure built up pretty fast. I think that my mechanic kinked the fuel rail, so ill take off the plenum and see, another gasket to buy ugggggh! Thanks for all the help guys,

Kinked rail shouldnt affect pressure negatively…Also, use the metal plenum gaskets, I reuse those things religiously LOL