05 Grand Am Hard Starting

[emiracleworker1]

This is my dad's car.... Today it began taking a while to start. It will turn over, just doesn't start. If you crank on it a while it will eventually start then runs perfectly fine. The problem occurs both cold and hot. I tried cycling the key 5 times, each time until you hear the fuel pump shut off then cycle again... it's starts just fine doing that. If you shut it off then try to restart, it'll just sit there and crank until you cycle the key a few times. There's no check engine light or OBD codes.

The fuel pump only runs for a second or two when you flip on the key, which tells me it's not having a problem coming up to pressure... and I'd imagine if I had a fuel pressure issue, it wouldn't be running smoothly and I'd have some hesitation, right?

Any ideas of where to start looking? Thanks in advance for any help.

[thephantom1492]

Hook up a fuel pressure gauge.

Basically, there is a check valve in the pump that prevent the pressure from dropping.

The 2 seconds priming is really just a timer. It do not even check the pressure (and actually there is no fuel pressure sensor).

This would be the first thing to check: if it hold pressure.

[emiracleworker1]

OK... thanks and I was slightly mistaken when saying it's acting up hot or cold. I tried starting the car this morning after sitting all night and it fired right up. Had my dad drive it for his errands today and wouldn't restart unless he cycled the key a few times. I looked at it tonight after about 5 hrs of it sitting and was still acting up. Once running, it won't let me rev above 4000 RPM... it runs strong up to 4000 then the motor just cuts out till it falls to about 3700. If I hold the pedal down it'll just surge between 3700 and 4000.

I do have a fuel pressure tester on order, so won't see it until Tuesday or so. Are these symptoms still sounding like a fuel pressure/check valve issue or are there other things I could be looking at while waiting for the tester?

Once again, I assume with no OBD error codes that I can automatically rule out things like the crank position sensor or ignition issues, as those would all signal an error code if something wasn't functioning properly, right?

[GTP Dad]

The rev limiter in the computer will not allow the car to rev above 4000 when in park that is why this is happening. I suspect that you have a faulty fuel pressure regulator on your car as it is allowing the fuel pressure to drop when hot. It appears that the fuel pump is working fine since once started the car will run and perform just fine.

[xeroinfinity]

since you mentioned you have to cycle the key several times, it is possible the ignition switch is going out..

[emiracleworker1]

OK... back to the drawing board. Ignition switch is fine, fuel pressure checks fine. Still no OBD codes. A mechanic has had it about a week now and he's completely lost as well. It's definitely a warm/hot issue and will not act up at all if it's cool/overcast outside or if the car has been sitting. Any other thoughts?

[Tech II]

While he had it, it probably never happened....intermittant problems that don't occur are the hardest to fix....

You say you checked for codes....I'm sure PCM codes were checked....but were BCM codes also checked?

First thing to do is eliminate the fuel.....need to attach a fuel gage and leave it on.....then when vehicle won't start, fuel pressure can be checked....

If it won't start and fuel pressure is ok, then check for spark....if ok, then spray carb cleaner into intake....it it starts and runs as long as you spray, could be a security system problem(when there is a problem, the injectors won't fire).....

[danielsatur]

Also see AF Similar Thread http://www.automotiveforums.com/vbul....php?t=1082304