Fuel pump/pressure question

[240ShaneX]

Hey guys, I am having problems with my car starting and think it might be my fuel pump. Hopefully you can help! If I try to start the car (hot or cold) it will just crank and crank 7+ seconds before starting. Now if I prime it by turning it to on, back to off, then back on then start, it usually starts right up. I checked the fuel pressure with the engine off and it was about 33psi the first prime, then 39 the second prime (normal spec is about 42 with no vacuum). When I started the car it dropped to about 36psi. Now, once the car's started, it revs smooth and strong with no hesitation. I replaced the fuel filter just to see if that was it, but no difference. This kinda leads me to think its not the pump since it runs so good after its started, but then why would it need to be primed to start? Thanks for any advice!!!

[compactfean]

You have one of two things going on. Rather the fuel pump has a pressure relief valve going bad causing fuel to blead back into the tank., OR the fuel pressure regulator is bleeding off fuel so your fuel has to work a little harder. From my professional experience, if mean more toward the fuel pump.

[240ShaneX]

Thanks for the reply. Is the pressure relief valve part of the pump itself, or is it something I can replace without buying a new pump?

[compactfean]

Its part of the pump. Its a safety device built in, In case your pressure regulator goes bad and pressure goes too high. The rest of the pump will fail soon after.

[240ShaneX]

I forgot to ask, does that also necessarily mean my FPR is likely going bad?

[compactfean]

No, and actually when fprs go bad the usually are the opposite. Usually a bad fpr will cause high fuel pressure and rich conditions.

[SR86]

Have you checked your voltage at your fuel pump? It fluctuates depending on how you're driving, but during startup it should have a full 12+ volts.

[240ShaneX]

good to know, thanks! Ill check it