Bad Fuel Pump???

[dohc v6]

How do you know if you have a bad fuel pump. I start my car up, and it drives, but when I am driving the car will like to shudder only sometimes. Also if I try to go into boost, sometimes it wont let me, it will feel like I am hitting a rev limiter at 3k. I di hook up a fuel pressure gauge and get 42 when its priming and when it stops it goes down to 0 in about 10 seconds.

[dohc v6]

just started the car, the needle on the psi gauge goes from 34-36 when the car is running.

[Crazy K]

well... obviously something is wrong. maybe the pulsator in the tank is bad? or the fuel injectors are havnign leak down? or the FPR is bad?

[rockfangd]

sounds like an internal leak somehow. It should hold pressure for at least 5 minutes after the key has been cycled off

[dohc v6]

Injectors are not leaking, I checked them and they are brand new, 300 miles on them. The pump is a walbro but its been ran dry twice, on accident.

 

Mark

[1990lumina]

If you lose static pressure so fast I'd suspect the check valve in the gas tank/fuel pump is failing and allowing the fuel line to drain back to the tank.

[rockfangd]

either that or a return line leak. to lose pressure so fast definately means a problem.

[jake63]

As stated already, the "fpr", or fuel pressure regulator could be bad. It is designed to slow flow after the injectors to keep pressure up.

[dohc v6]

I replaced that, and I checked the vacuum line going to it and there was no fuel in it.

[Canada]

Just because the FPR isn't leaking fuel out the vacuum line doesn't mean its leaking fuel down the return line.

[dohc v6]

Yes true, but 90% of the time it will leak in the vacuum line. Plus I ran the pump dry twice. So I am going to guess on this one and say its the pump. If its not the pump I will replace the FPR.

 

Mark

[dohc v6]

A+, fixed the problem. It was the pump after all. thanks guys. Now all I have left to fix is the MAF