Dead 1990 Pontiac Grand Prix

pontiac

#1

I’ve got a 1990 Pontiac Grand Prix LE (3.1L) which recently died in a parking lot. The engine suddenly quit with a hissing sound. Fuel pump? Probably not, it’s running when the key is ON and the lines are pressurized, says the schrader valve. The spark plugs are sparking, the engine turns over just fine and beating on the fuel tank didn’t help. I didn’t even see it coming. Any thoughts?


#2

Since you are done; if the car is worth saving at 19 years old… What am I saying? Make your best bet and find another car, like a seven year old. If your present car isn’t totally broken by now, it will be soon. You’re not chained to it after all.


#3

i checked the fuses and relays and they’re all still good. there is nothing obstructing the airflow. i’m thinking it’s in the wiring. college = this car or nothing, sorry.


#4

You could see if spary some starter fluid into the intake helps get the engine fired up. There may be a fuel delivery problem. There also may be a timing belt problem. Checking the compression would verify that.


#5

No timing belt on this thing. It might be productive to do a quick “field” compression test of pulling out one of the plugs and holding your thumb over the hole while someone cranks it (with the plug wire somewhere it won’t shock you!) but I don’t think there’s too many instant lack of compression issues that can happen on this engine.

The hissing makes me wonder if maybe a big vacuum line like the brake booster hose or something might have come off or broken. A big enough vacuum leak like that can cause a no-start. I agree with cougar that doing the starting fluid test will help further isolate which system is the problem, though if this is a version with a MAF sensor, make sure you’re not spraying the fluid through that. Just because you’ve got spark doesn’t mean that it’s hot enough spark delivered at the right time, nor does just having fuel pressure mean fuel is being delivered in the proper ratios.


#6

the starter fluid ran the motor for a few seconds. it could be the injectors/ECM. what else could cause a no start? are the valves a factor at all? as for bad fuel, i’ve driven 100 miles on this fuel.


#7

turns out, it was the ecm. thank God i don’t listen to cynics who have nothing better to give than bad, misinformed advice. if they all stayed home and read their haynes manual, maybe they wouldn’t have to go out and buy a new car when a problem comes up that can’t be diagnosed with an OBD II that they borrowed from advance auto parts. make sure your brother-in-law takes the afternoon off to show you how to clear the codes


#8

I am glad it worked out for you. dodgevan does not often give bad advice, he may have been thinking it was something more serious.


#9

Thanks for the update and glad you got it fixed. Since the starter fluid trick worked I would guess something went wrong with the injector circuit of the ECM.


#10

No one advised to check the ECM (engine computer) because: they have a very low failure rate, and, it takes some skill and knowledge to troubleshoot the ECM.
The next step, after the starter fluid test (and, it started), would have been to check any accessible fuel injector with a 'noid brand test lamps. This would reveil if the fuel injector driver signals, from the ECM, are reaching the fue injectors.

How technical, and to what volume, should answerers go?


#11

go 'til the car is rolling again


#12

yeah, i should apologize, i wasn’t having a good day when i posted that little something extra on the end there


#13

Sorry I didn’t check back with you. No need to apologize, I have certain cars that I always recommend getting rid of when they reach a certain age or a certain mileage limit. Not everybody agrees with me. Would they be better off to agree with me? It depends on how much money is in the budget when a problem happens. I don’t expect all posters to say whether or not they have a certain amount of money. It’s a shot in the dark as to when a car will give out. I just try to predict when a car has reached the point of bad return. The problem a car is having today has little to do with it. I’m not misinformed, just unresearched.


#14

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