OT, Chevy Lumina up and died!

Hint: If you have a little propane torch, stick it in the air cleaner and turn it on, and crank the motor. If the engine runs, then your injectors are probably the problem.

I had a 95 Chevy Astro one time that wouldn"t start unless you poured gas into the inlet, then would run perfectly once it started. Turned out to be a fitting on top of the in-tank fuel pump leaking. Found it by monitoring fuel pressure during cranking with a guage connected to the fuel rail test port. Injector pulse width is set to a fixed value during cranking, and then is determined by engine speed/load once it starts and the computer closes the control loop. In this case, there was enough pressure once it started that the computer could compensate by keeping the injectors open a little longer, but there wasn"t enough fuel pressure to start.

But a cheap air conditioning pressure guage to check fuel pressure with. The fittings on the old R-12 systems are the same as the fuel rail schrader valve.

Have you dumped the codes to see if the computer is showing some particular problem?

Keith

You really need to check the fuel pressure at the fuel rail. If it doesn"t come up to the specified value, plug the return line where it comes out of the regulator (squeezing the hose with a pair of vice grips generally works) & see if the pressure comes up. If the pressure comes to the right value when you close off the return line, the pump is OK & you probably have a bad regulator. If the pressure doesn"t come up to the spec"d value, then you have either a pump problem or a leak somewhere in the tank.

If you"ve replaced the pump, the prime suspect is the little rubber "pulsator" (I think that"s what its called) on top of the pump itself.

Keith

With NO vacuum to the fuel pressure regulator, the regulator will be at it's MAXIMUM pressure setting.

As vacuum is applied, it acts AGAINST the spring pressure on the diapragm, reducing fuel pressure a few PSI for better fuel economy at light load or idle.

Most regulator failures are diaphragm leaks that dump raw fuel into that vacuum line, and from there, into the intake.

About the only other way the regulator could fail would be if the spring broke, and there was no pressure against the diaphragm.

Then, without a buildup of pressure in the fuel rail, all the fuel would pass through the regulator, and through the return line, back to the tank.

Get a pressure gauge on there, and see what the pressure actually is. You've thrown a lot more money at it than what a fuel pressure gauge would cost!

If the fuel pressure is up to spec, you've got a problem with the 'puter cycling the injectors.

I had a 91 Lumina, and it was, and still is an excellent car.....exwife has it. Once upon a time it ran hot and I could not figure why. Took it to Chevy garage and the mechanic said before he even looked at anything, he knew what it was. There is an aluminum fitting under the intake someplace, that will go bad and leak. You will never find it looking from the outside. Sure eneough, I watched him tear it apart and out came this corroded fitting. Cost me $191 to get it fixed. Worth it? Damned right! The car was fixed in one day, I would never have found it and I didnt suffer any scraped knuckles or invent new cuss words. It makes no difference what you paid for the car ($50 or $5000)..if it is a good reliable vehicle, get it fixed and move on.

Allan