My 99' GP Needs some help :/

[Migueldeluna]

Hey guys... new to the forum..

Well as I stated, I've been having some problems with my Grand Prix and I can't seem to pin point what the problem is... I have however narrowed it down.

So one day my car just doesn't turn on. I turn the key and it seems like it's about to start but as the rpm's go down the car dies. My dad claims it could be the fuel pump but I've seen some posts that have said that if you can hear the fuel pump.. it should be good.

I took it to autozone to get the computer checked and pretty much it said it was backfiring that it could be low or high fuel pressure... ignition system fault... a vacuum leak.. or injector fault.


Now I know I should be checking all of this.. but I'm trying to hopefully cancel out the more expensive faults first. Which in this case would be the fuel pump or the Fuel Pressure Regulator.
I checked the fuel pressure regulator and the vacuum line wasn't leaking gas...

What could it be?

Oh btw.. if I let the car sit a while.. (couple of hours) it will eventually start and keep running for about 5 minutes before it dies again.

My uncle suggests it could be the fuel pump.. and that it may be overheating.

[NaturallySmashed]

hmm.. probably fuel pump

[Migueldeluna]

So I bought a fuel pump..... Put it on there... Still same problem.... Now I need to catch a ride to work tomorrow. Help is appreciated!

[Liquifire]

crank position sensor? Just an idea........

[blueguy]

'99 Grand Prix GTP?

If so...

[NaturallySmashed]

'99 Grand Prix GTP?

If so...

nice

[Migueldeluna]

'99 Grand Prix GTP?

If so...

Nah... sorry forgot to specify.. it's the GT

[Migueldeluna]

crank position sensor? Just an idea........

Thanks

I'll have a look at that...

I've checked just about everything.. I changed my spark plugs for the second time in 3 months.. it worked for a bit but it did it again.

The computer stated vacuum leak as a possible cause... so I'm going to check the PCV valve.


:EDIT: Also the reason I changed the Spark plugs was because they seemed carbonized.

[Liquifire]

if you are looking for the vacuum leak, take a can of carb cleaner and start spraying anywhere that there should be vacuum........hoses, connections, etc. The RPM's will pick up if you spray in the area of a leak.

[Migueldeluna]

crank position sensor? Just an idea........

I'm going to check this tomorrow asap..

Do you know if it's normal for smoke to come out behind the engine?

It seems to do that a lot as I try to start it.

For a second I assumed it could've been the catalyctic converter... but I removed it and tried to start it and got the same result.

[Liquifire]

It is normal to get a little smoke(from condensation buildup in the exhaust) but not a lot every time you start it out of the exhaust, but what do you mean smoke from behind the engine? If it is coming out of the engine compartment the answer is no.(If you do it could be as simple as an oil leak) What color is the smoke? How long does it last? Does your coolant and oil look normal and are they at the proper levels?

[Migueldeluna]

It is normal to get a little smoke(from condensation buildup in the exhaust) but not a lot every time you start it out of the exhaust, but what do you mean smoke from behind the engine? If it is coming out of the engine compartment the answer is no.(If you do it could be as simple as an oil leak) What color is the smoke? How long does it last? Does your coolant and oil look normal and are they at the proper levels?

I guess by saying behind the engine I mean by the exhaust.. It is not much.. but it's black... it could be an oil leak or just the exhaust? It usually just lasts like 5 seconds max and just happens as I start it. And yes both the coolant and oil look normal and at proper levels.

[Migueldeluna]

On the crankshaft position sensor do you loosen the bolt clockwise or counter-clockwise?

[Migueldeluna]

not the crankshaft position sensor either.... could it possibly be the map sensor? It keeps dying when it gets below 1000 rpm It starts for about 5-10 minutes.. and then it dies. After it dies... it won't start again.... It's almost like something's overheating... something has to be overheating.. Once I let it cool down... for hours.. it'll start again... then die in 5-10 minutes. a cycle... I'm scratching my head. help?

[Migueldeluna]

To summarize everything I've changed on the car to try to fix it...

and well to show how much I've spent :/...


Fuel pump
PVC valve
Crank Shaft Sensor
Fuel Pressure Regulator

changed all those and it's still messed up

[Migueldeluna]

Wow... anyone?

[Liquifire]

MAF or IAC valve? I dont know.......just guesses at this point. It could be lots of things.....do we know if this is either fuel, air, or spark related for sure?? do you have access to a scanner so that we can see what happens in real time? This would be a huge help.......do you know what the fuel pressures are for sure?

[Migueldeluna]

Hmm... I thinking about my alarm...

could that be it?

I heard it stops the car... umm at times it just goes off by itself.

[Liquifire]

disconnect it and see.........I have never heard of this type of symptoms coming from an alarm though......

[InfidelRebel]

Did you check your battery connection? I had a problem where my keys got stuck in the car sometimes, and the alarm went off randomly. After trying everything I eventually realized the negative connection to my battery was loose.