Hello!

I just swapped over to a 350 carbed from a 305 tbi motor, and I'm having issues with the fuel pressure. I have a mallory 4309 by-pass regulator and it is set at 6 psi. The motor ran yesterday and it was running really nice, but today I go try to start the motor and it doesn't keep running. My fuel pressure guage reads 3 psi when the pump primes, but once it starts fuel pressure doesn't keep going. My oil pressure perfectly fine. Is it the pump or the relay that is causing this problem?


Thank you

Chris

 

well once the engine is running the oilpressure sending unit is really the switch for the fuel pump so as long as the engine is running so should the pump

 

well do you think it's the pump? It does prime properly so I don't think it is, maybe its a faulty oil pressure switch?

 

where are you getting your FP reading from?

 

I have a guage installed after the FPR and before the carb.

 

then why are you only getting 3 psi after the pump has primed? souldnt you have about 5-6 as the pump is probably at 12-13

i am guessing regulator

 

Im not 100%, I had 6 psi when the carb was running. It was a tbi car, so the pump shouldn't be hard on the regulator. Is there a way to check the regulator?

 

yep try and get a FPgauge between the pump and the regulator that way you will know how much the pump is actually putting out and what you have after the regulator

 

k i just tried to start it again and it appears that there was a jump from 0-3 psi only once and then it never happened. I think it's probably the fuel pump.

 

I will definetly check that out, I think it might be the fuel pump.

 

Yeap!! It was the fuel pressure regulator alrite, got that replaced with another unit, and it runs! Thanks for the help!!!