PontiacBonnevilleClub.com

To start, i have noticed for a long time...really since i have owned the car that while starting, once it fires...it seems like the car drops to low low RPMS..then jumps back up to idle.....maybe this is a normal Bonneville thing though.

So, this morning, i go out to start the car...and it cranks over and acts like it is gonna fire...then just sputters to nothing. crank and crank.....acts like it is trying to fire...but again......won't start. I turn the key to hear the fuel pump run and shutoff then try to start.....always have done this.....still no start.

I was running late and couldn't put tester on before i left this morning to see if there are any codes. car ran fine when parked saturday evening. no problems at all.

I figure tonight, i will check for any codes, then start by checking fuel pressure. Anything else i should consider? EGR? Ignition module? Any common hard or no start issues with these cars?

EGR won't prevent a start unless it's got a severe leak, and like a vacuum leak, would typically cause a high idle, not low.

Fuel pressure isn't likely to be an issue if you don't have any serious driveability problems at higher rpm's.

Best thing to start with is to disconnect the MAF sensor (square sensor on the throttle body) and start the car. If the symptoms are greatly relieved, clean the MAF sensor gently (the delicate wire filaments) with a q-tip and rubbing alcohol or MAF cleaner available at your local auto parts store.

If that doesn't make a difference, let us know and we'll get started on the next steps. The two primary components to cause a low idle would be the IAC (idle air controller) and MAF (mass airflow sensor). The MAP sensor, however, can also be a culprit.

i will give those things a try.

i should clarify my post though. My statement of the way it would start and drop low then come back up...that was a common thing...when it did start at least since ive bought it. wanted to throw it out in case it may have been a sign of what i got going on now.

as of right now, the car isn't running/starting at all. it just cranks and sputters.

will report back tonight once i get a better look at it. car just turned over 90K as well.

On the chance that it is now flooded, try putting your foot to the floor while cranking. This shuts off the injectors and allows maximum air into the engine while cranking.

Checked for codes, nothing.
Checked fuel pressure, all good
Unhooked MAF no start.

Unhooked Ignition module and took in to get checked. It came back as bad. So, looks like it was the ignition module this time around.

Weird how it ran fine when i drove it home last time and then suddenly goes bad.....

Good luck with the ICM test. I've seen test results show good ICM's as bad, and Bad ICM's as good. Most test results I've seen or heard of were wrong. Let us know, but in my experience, bench-testing ICM's doesn't tell you jack squat.

any other ideas i can check on to try to pinpoint it down?

i really think my fuel system is in tact.

i unhooked the connection you stated and it still wouldn't start.

again, no codes being thrown

Have you checked for good spark? One way would be to pull both wires off from one coil at a time. A good spark should jump across the terminals. That could rule out the ICM.

FWIW, my son's '99 Grand Prix had a bad MAF sensor and he had symptoms similar to yours. Disconnecting the sensor did not change the situation. A news sensor took care of the problem. It is not an inexpensive part, so other things should be ruled out first. Do you know anyone that you could swap MAFs with?

i have them same problems with my car,but mine stalls while driving rpm drops to zero,i did the spray test on the coil packs and found they were arcing like crazy so i changed 2 out of 3 coil packs,car has not stalled in 2 days but rpm still drops to zero while driving,seems to do it when air temp goes under 40ish.

i still have my ICM out of the car. Was going to hit another store to let them test too just to make sure first store wasn't jerking my chain.

I can always put the ICM back on and try letting the coils arc as you stated...nothing hard about that one.

as for MAF swap, not sure i know anyone i could swap with.....any certain year range i would have to be in? lesabre/grand prix...all the same as mine??

its just odd that the car hasn't shown 1 problem even the day i last drove it. ran fine. then when i went to start it yesterday, just won't start....? wouldn't a MAF sensor show signs before just going? i guess the same could be said for the ICM though too.

all depends what the computer is seeing,why not just bring it to the mechanic and stop the guess work,60 bucks and they can diagnosis it,or if you know someone do it for free,it could be anything maybe crank shaft sensor,my car stall's becuase of that i forgot to mention that,just does not kick engine light.

Dealers here in our town are now 90 hr. Plus, i would have to have it towed up there, $40.

I could have a brand new ICM in the car for that and know i have a good one if nothing else since the car has 90K miles on it now.

i do see your point, i could be just throwing parts at it. Tonight, i am going to put it back on the car and check for spark from the coils. I can also test for signal off the ICM posts as well.

does your engine have the plastic cover on it? if it does check around the fuel injectors wires,ect.....last year i had a mice crawl upthere and it chewed some wires up.

does, but i removed it when working on it. i didn't see anything out of place as far as wires or hoses or anything doing a basic check-over on the car.

update.

took ICM to another store, checked fine. Brought it home and put back together.....pulled boots off of 1 coil at a time and cranked...all coils sparked across terminal.

Still no start

Did option stated above as far as possible flooding. Put foot to floor and cranked it....stumbled and started and then ran fine. Shut it off and started couple times no problems.

Smoked more then i would have thought it would have that first time...but then it cleared up after running...

How could the car have flooded when trying to start first time on monday morning after sitting from saturday evening through sunday???

Any ideas?

anybody?

im thinking of biting the bullet now and letting dealer run it on computer to see what happened to cause this now since it is running now and i don't have a clue what caused this situation. leary to drive it to work until i know for sure what caused it. 30 mile hike home doesn't sound fun right now in 15 deg weather

If you have the time next time it doesn't want to start, try pulling the plugs to see if any of them are wet. If there are one or two that are, the injectors for that/those cylinders are leaking.

i haven't had a no start situation on this for a few days now. took in to dealer to have them check things over, they said they didn't see anything in the computer or such that would indicate a problem to cause the no start.

now, i did notice when i came back that under the car back by where the mufflers would have been, that there was 2 black carbon looking stains on the garage floor. so, am i to assume my exhuast system is plugging up?