1990 starts, revs, then dies

[jim protiva]

I have a 90 that will start, then it revs up (leaning mixture?),then stumbles and dies. I swapped VAFs with a running car and that did not help.Broken wire between VAf and computer? Bad fuel pump relay? Can I temporally bypass VAF to cause fuel pump to run without imput from VAF?

Thanks, Jim

[jayber]

Verify fuel pressure

[dalebwilson]

+1 What Jayber said. I suspect you are getting a slight build up of fuel pressure that goes away quickly. Also, there is a fuel pump test connector (T shaped) located near the master cylinder. Jump it with a paper clip and listen for the fuel pump running. Fold the back seat forward, lift the carpet and remove the fuel pump. Check the fuel pump sock (pic below) and replace it. At 25 years old they get hard, brittle, varnished and plugged. You have another fuel filter near the inlet to the fuel rail. Replace it as well.

[jim protiva]

ok, i have 32 psi fuel pressure. It now mysteriously runs with out dying, but it will rev up to 4000 rpm on its own. while in self rev mode, the throttle is ineffective. new plugs which seemed to make it run smoother, but something is still wrong. Thanks again, Jim