Car starts hard,Fuel pressure problems

[LeafsFan13SHO]

I have a 95 ATX that starts hard. When running it has about 40 pounds of fuel pressure,but as soon as I shut it oh off it drops off to zero.I was thinking of replacing the fuel pump. Will this take care of it? Also, when i removed the Schrader valve from the test port on the fuel rail no fuel came out, but about 30 seconds later a whole bunch of air bubbles and gas came out. That doesn't look right. Any Suggestions?

 

[BlankDisk]

Before I changed my fuel pump, I noticed that the more gas I had in the tank, the more power the car had. Now it's no longer an issue since the new pump went in. So yes, the pump is no doubt the problem. Either that or there's a hole somewhere in the tank, but that's not too likely. So a new pump should solve it.

 

[F-22 Raptor SHO]

Welcome to the forum both of you. Having recently had fuel pump problems, I can offer up some advice:

Hard starts dont always equal bad fuel pump. Does the car start right up if you push the pedal to the floor while starting?

1: While the motor is running you should have 40psi. That tells me the pump is working. When you turn the key without starting the motor, the fuel pump will cycle for 1.5 seconds (the pressure at the rail should be 40 psi) which would also tell me the fuel pump is working.

2: when you shut off the motor, the pump shuts off and the pressure sould go to zero.

The only reason I am suggesting you troubleshoot things further is that replacing the fuel pump is no simple task and your problem could be related to something else.

 

[masho95]

F-22 Raptor SHO:
2: when you shut off the motor, the pump shuts off and the pressure sould go to zero.

When you shut the car off fuel pressure SHOULDN'T go to zero. It's supposed to hold pressure in the system for quite a while. Change your fuel pump and you should be all set. There is a check valve on the pump that should hold the pressure and it's obviously not working.

 

[ckinart]

F-22 Raptor SHO:

1: While the motor is running you should have 40psi. That tells me the pump is working. When you turn the key without starting the motor, the fuel pump will cycle for 1.5 seconds (the pressure at the rail should be 40 psi) which would also tell me the fuel pump is working.

I could be wrong here, but I'm fairly certain that at idle, fuel pressure at the rails should be in the neighbourhood of 28-32 psi, and closer to 40 psi if you disconnect the vacuum hose to the fuel pressure regulator.

Regardless, I agree with masho95 on the check valve.