Mysterious stalling car


#1

i have a 200 pontiac sunfire. until 3 days ago it ran great. the other day i was on my way to work at 70mph when the engine just stopped running. pulled over to the berm turned the key and it started right up…continued on to work went home after, no problems…just a glitch i thought. the next day same thing happens except this time it doesnt start right back up,it took about 15 mins. to get it started again but this time i turned around headed straight to my mechanic dropped off the car and went to work in my wife’s van. later the mechanic calls me, says he test drove it extensively under all conditions put it on the diagnostic thing and could find no problems. i had him put a fuel filter on just for GPs. (the car has 145,000mi and its never been changed). next day i drive to work no problems…coming home, lots of problems stalled out the first time and there was no getting it started again. a guy pulls up behind me on the freeway berm and offers to push me anywhere i want to go. after some discussion he listened to the car as i tried to start one more time. he suggested it might be the fuel pump. ithought this might be logical and allowed him to push me off the highway and several miles toward anything that looked like a repair shop. at some point i tried and was successful at starting the vehicle we pulled over i thanked him and gave him all the money in my pocket ($26.00). icontinued on my way towards home on surface sts. in rush hour very frustrating…so idecided to head back towards the freeway. i no sooner got on the freeway and up to speed and…Damn, it stops running again. it did start up again relatively quickly this time and another time on my journey back to my local mechanic. that was yesterday. today the car sits until someone differant can look at it on monday, because the primary mechanic expressed little hope of finding anything wrong with the car.

ANYBODY GOT ANY IDEAS?



thanx

sralph


#2

You may have a faulty Idle Air Control valve or a dirty throttle body.

A vacuum leak (air plenum or hoses) can cause stalling also.


#3

[b]There are two things that can cause this sort of problem. One is the ignition module, and the other is the crankshaft position sensor.

If the problem doesn’t show up for the mechanic’s, then what you can do is carry an extra sparkplug in the vehicle. The next time it stalls, and you can’t get it restarted, remove one of the plug wires from a sparkplug, and plug the extra sparkplug into the plug wire and lay it on the engine. Now try cranking the engine over, and see if there’s a bright blue spark at the sparkplug. If not, the ignition module and crankshaft position sensor become suspect.

Tester[/b]


#4

The engine sensors could be suspect as Tester suggested. If they are the cause then there should be a code listed in the ECU the mechanic could clue in on. Another real suspect is the ignition area as Tester also mentioned and would put most of my money on it if I was betting on the cause of this trouble. There may be a power source problem to the ignition system due to a faulty connection. You may be able to locate it by tapping lightly on suspected areas with a screwdriver handle. Possibly a faulty ignition or fuel pump relay is the cause. I really think the cause is due to an electrical problem somewhere.

This kind of problem is really frustrating since you never know where things will act up and leave you stranded. If you don’t have any error code clues to go by then the screwdriver trick may be your best bet to solving this.


#5

Ha! I’m not the only one. I’ve been dealing with this problem for two years on my 99 grand prix.

The mechanics have told me that fuel pumps last at least 120,000 miles so it could be the fuel pump. A fact about fuel pumps, though. When their time is up, they go. They don’t linger around long. So, don’t get a new fuel pump unless you are darn sure because that is probably the most expensive route to go.

If I were you, I would throw a new fuel relay in it because that seems to be a common problem with GM cars. It costs about $40 and takes about two seconds to put in your relay box. You can do this yourself. Just look at your owner’s manual.

It could be the ignition module or damaged wires in the steering column. That is also a good shot, but that may cost you up to $400 for parts and labor.

i’ve been reading about this a lot and here are some other things I’ve found:
damaged spark plug wires
loose connection with the SRS airbag wires. Apparently the airbag is on the same circuit as the fuel pump so when the airbag goes off, then the fuel pump stops (not sure if this is really true, but it’s worked for at least one other person)
bad computer (another very expensive problem)
any kind of wire harness frey (hard to find)

This is the HONEST TRUTH. There isn’t a mechanic out there that can fix your problem until you have a hard failure. They can only guess.

I seriously doubt it is the EGR valve. Some people say that is the problem, but usually you have rough idling with an EGR valve with carbon buildup


#6

There is a way to bypass the computer and the fuel pump relay to power the fuel pump directly. It’s included on many GM cars. Under the hood, on the left side(?) is what looks like a wire somebody forgot to connect. When the car stalls, use a piece of wire to jumper that wire to the positive side of the battery. You should hear the fuel pump run and maybe be able to start the car. If yes, tell your mechanic.


#7

Neato. I see the wire that “somebody forgot to connect” just below/behind the battery. What happens if the poster does what you said and the car decides to start? Could there be an overload somewhere?


#8

Good point. An in-line fused wire (available at auto parts stores) should be used, just in case there is a short in the wiring. This jumpering is more of a test than a temporary fix; but …This test will tell the mechanic that the problem isn’t the fuel pump, itself; but, just as important, it won’t tell him that it IS, either.