c4nate

OK! I have a 1985 corvette bone stock 160,650 miles it runs good but I cant figure out whats going on. Last summer I noticed that my car would stall at a light when at operating temperature, and will stumble when I give it gas. I also noticed that the fuel pump doesnt run for the 2 seconds it suppose to when I turn the key to the on position.......I know it sounds crazy but the gauge is showing there is no fuel pressure when I turn the key to the on position but it still starts and the pump sounds strong(After 10secs of cranking). I checked the fuel pressure when the car was started and it read 37-38 psi. Could my pump be going bad or am I aiming at the wrong thing?

Y-ME

Should pressure up when you hit that key.

Cliff Harris

The ECM turns on the fuel pump relay for 2 seconds when you turn on the ignition. Sounds like that is not happening. Probably a bad relay. They are pretty cheap so it's probably easiest to just replace it. It could be a wiring issue.

If the fuel pump relay fails there is an oil pressure switch backup that turns on the fuel pump when oil pressure reaches 4 PSI.

For the stalling issue do a minimum idle adjustment:

http://forums.corvetteforum.com/1570563689-post1.html

c4nate

I just replaced the fuel pump relay and the pump still doesnt come on for two seconds but it still starts and runs. If I gas it from a dead stop or try to do a donut the car stumbles like its thirsty for fuel.???

Cliff Harris

Pull out the fuel sender assembly and look inside the tank. There is a plastic tray in the bottom that holds fuel when cornering. The fuel pickup sits inside that tray. If the tray comes loose and moves out of position you can get the stumble when the fuel moves away from the pickup. The tray is glued to the bottom of the tank.

This excellent article by Frizlefrak will show you how to take the fuel sending unit out:

http://forums.corvetteforum.com/c4-t...h-article.html

Cliff Harris

Did you notice in my earlier answer where I said, "It could be a wiring issue"?

You need to get a digital meter or test light and start troublehooting.

ccrazor

Here is the drawing for the fuel pump, this is for the start problem, for the stall problem you might want to connect a pressure gauge and tape it to the windshield to check pressure when the problem occurs..