fuel pressure

[procrstinator]

ive got a 99 3.4 70000 on it ......haynes book says fuel pressure with key on should be 41-49 lbs. ive read some other threads that say pressue should typicaly 56lbs. anybody? i read 41lbs on mine -key-on engine off

[BNaylor]

There are differences in fuel pump pressure depending on your year model Alero. The 1999 3.4L Alero had the older design fuel pump which puts out less than the fuel pumps on the 2000 and up Aleros with 3.4L. Therefore, the 41 - 49 psi is probably corrrect, however, if you are getting 41 psi you are borderline.

What problem are you having?

If you are getting 41 psi in fuel pump prime then what are you getting with the engine running with and without the vacuum line connected at the fuel pressure regulator?

[procrstinator]

my alero has been down for a few months.im the one that put bad fuel in.and it ran good the rest of the day.parked it that night and the next morning it would crank but no start.coincedence? i dont know Ive changed the fuel filter,changed the injectors,plugs,drained the bad fuel,took the pump modual out and screens were good.i have ignition control modual voltage,coils have correct resistence ,i have 7x crank sensor signal,temp sensor is good maf sensor is good.batterie voltage is 12.4.i have power to the injectors and so i was going to check at the injector harness for sigal from the pcm.I had it towed to a shop who calls me to say he refuses to work on it cause when he hooked it up to his $ 7000 machine it blew a fuse.he also said the alternator got beet red hot with key on .i have yet to see what he is talking about ..doesnt get hot for me .lol .all the fuses and relays are good .HELP!!!! also the day before it died i had kragens test the batterie and alternator .they passed the test

[BNaylor]

Oh yes, I remember. I can understand your frustration. Out of curiosty have you pulled at least one spark plug and checked spark? I see you mentioned the 7X crank sensor but what about the 24X crank position sensor? It is the main sensor that generates ignition timing positioning to the ICM module and coil packs. Located behind the harmonic balancer pulley.

[JTrujillo86]

First thing I would have checked were the plugs/wires or coil packs. Usually thoguh, won't the car run, albiet rough, with a bad coil pack?

- Jeremy