Fuel pump problem? maybe?
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Joined: Oct 2004
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From: Bay area, ca.
Fuel pump problem? maybe? Ok, so... I just got my 454 in the car, up and running.
With the old motor, until the day I pulled it out, I had no problem with fuel pressure or bucking. Mods in sig.
I have a fuel pressure guage hooked up to my driver side fuel rail. The first time I primed the pump before I started the car, it only primed to 45psi. Primed it a couple more times and got it to 58psi.
I've only driven the car about three times so far.. I was having issues with vacuum leaks, idle problems, surging, bucking, stumbling and backfiring.
I fixed the vacuum leaks and found out that a loose plug was causing the backfiring and stumbling.
Now that I'm paying attention, the car NEVER primes up to 58psi anymore. It primes to about 42 for about a second, then drops to about 38 (before I start the car) Once I start the car, it jumps to about 48 - 50psi.
I don't take the car above 3k rpm yet, but even at that rpm it's bucking and surging. Other then that it runs smooth. It's just when it bucks like crazy.
I dont see why the guage would be bad, or why the pump would be bad. The car sat for about a year before I got the motor built and back in the car. Have had about a half a tank idled / driven through it, so I know it's not the gas.
Also, it loses about 10 psi at the guage in about 5 minutes. I don't know how normal that is.
Think it's actually the fuel pump..? maybe tune related? It's only got a map for the injectors and thats it so far... it's running on the tune from my old 427. I don't wanna take it to get tuned with a fuel problem, and I dont wanna buy a fuel pump unles i'm sure that's the problem.
With the old motor, until the day I pulled it out, I had no problem with fuel pressure or bucking. Mods in sig.
I have a fuel pressure guage hooked up to my driver side fuel rail. The first time I primed the pump before I started the car, it only primed to 45psi. Primed it a couple more times and got it to 58psi.
I've only driven the car about three times so far.. I was having issues with vacuum leaks, idle problems, surging, bucking, stumbling and backfiring.
I fixed the vacuum leaks and found out that a loose plug was causing the backfiring and stumbling.
Now that I'm paying attention, the car NEVER primes up to 58psi anymore. It primes to about 42 for about a second, then drops to about 38 (before I start the car) Once I start the car, it jumps to about 48 - 50psi.
I don't take the car above 3k rpm yet, but even at that rpm it's bucking and surging. Other then that it runs smooth. It's just when it bucks like crazy.
I dont see why the guage would be bad, or why the pump would be bad. The car sat for about a year before I got the motor built and back in the car. Have had about a half a tank idled / driven through it, so I know it's not the gas.
Also, it loses about 10 psi at the guage in about 5 minutes. I don't know how normal that is.
Think it's actually the fuel pump..? maybe tune related? It's only got a map for the injectors and thats it so far... it's running on the tune from my old 427. I don't wanna take it to get tuned with a fuel problem, and I dont wanna buy a fuel pump unles i'm sure that's the problem.
