I have a 1985 z28 with Tpi. When I hit the gas the motor dies. My fuel pressure gauge does not move when I check the fuel pressure with just turning the key over and letting the fuel pump run, even when I clamp off the return hose. When the car is idling the fuel pressure is at 14 or 15 psi. The service engine light does not come on when I turn the key on either. This car has sat for 4 years as well. Can anyone point me in the right direction? Im not sure if the ECM can cause this or if it would be a fuel filter or fuel pump issue.

 

You have no fuel pressure with just the key on/engine off and have 15 psi with the engine running. Sounds like the fuel pump relay is not sending power to the pump and the oil pressure switch is providing power when the oil pressure gets high enough. Since it's been sitting, change the fuel filter regardless of if it's the problem or not. The ECM has no control on fuel pressure. You could have a bad pressure regulator (check the vacuum line going to it, if it has fuel in it the regulator is leaking), a leaky fuel injector, or a weak pump/ low power or ground going to the pump. And above all your pressure gauge could be wrong.

 

Could also be the rubber line in the tank that has gone bad or even a bad pump.

 

My money is on the pump.

 

Gonna point you to a nice new Walbro Pump.

And since it's been sitting, while you're at it, a fuel line flush and new filter when complete.

JMO....might want to look into new injectors while you at it.

 

Thanks guys! I'm positive it is the pump now. I ran a jumper like to have constant power to the fuel pump and it still only gets up to 15 psi even after I changed the fuel filter. I am going to look into new injectors if they wont hold their pressure after I put a new fuel pump in. One more question though. I do not have an oil pressure switch on my car due to having a manual oil pressure gauge. Would this cause any problems with my fuel pump? The fuel pump does run with the car running and with just the key turned over right now.

 

The oil pressure switch is the back up for the fuel pump relay so if the relay dies while driving the engine doesn't just die. The fuel pump should still turn on if the oil pressure switch is there or not but the fact that when you crank long enough, you get fuel pressure sounds like the oil switch isn't the problem. Sounds still like a problem with the fuel pump relay circuits. I couldn't find the 1985 diagram so this is the 1986 diagram, it could be a little different. http://austinthirdgen.org/mkportal/m...ine_wiring.gif

As far as your injectors leaking...pinch off the fuel return line while you build fuel pressure. If it holds it's a problem at the tank. IF it drops it could be the regulator or injectors leaking.