[Spudy]

I have a 2000 Pontiac Grand Prix that keeps shutting off while driving. Been an on going problem. I cleaned the battery connections because they were bad but other then that i am kind of at a loss. It start right back up if you pop it in neutral and start it but tonight we had to crank it a few time and wait a few mins. After we got it started it died again within a mile but started back up right away while coasting and got us the 5 miles home. Kind of leaning towards a fuel problem. Was wondering what everyone thought and if anyone knows of any test to find out more. It just comes and goes.
Thanks

 

[Kodiak450r]

check fuel pressure and spark from the coils. see if they are all sparking with the same intensity. one of 2 things either the ignition control module is bad or the fuel pump might be going bad.

 

[Spudy]

well i checked the fuel pressure and it is right around 47. Also was able to open up the end of the hose and drain the gas into a tank and the car never died or sputtered. The weird thing about this is when it does shut down while driving it is like hitting the key. Never spits or sputters at all just shuts off.
How do you check the intensity of the spark? I know how to check spark but unsure what you mean.
Thanks

 

[Spudy]

btw this has the 3800 motor in it.

 

[Kodiak450r]

ok well if it's doing that then it probably isn't a coil pack going bad. usually they will produce a very weak spark compared to a good coil. i'd start looking at wiring issues and or the ignition module going bad. ICMs will usually fail when they get hot.

 

[Haggar]

Interesting, a friend of mine at work had his die on the road this week. It will start, then run a few seconds, then dies like a switch is cut off.

He's researching something in the fuel pump power circuit, I guess the circuit feeds power straight to the fuel pump on crank, but then feeds it through a large power resistor in run. The resistors have been known to fail and cause these issues. I think its to allow higher voltage (higher pressure) during start as a bit of fuel enrichment, especially in the supercharged versions.

 

[Haggar]

See here:

http://rmcgp.clubgp.com/fpresistor.html

 

[Fuel Fire Desire]

I had this same thing happen to my 1990 olds 88 (same platform as the GP). The positive lead going to the starter had frayed down to bare wire and would occasionally short to the crossmember. It acted as though I turned the key off for a second or so, instantly killing everything, but then I'd get electrical right back. I could restart as normal while coasting.

 

[Spudy]

mine has always restarted right away and was able to be drove for anywhere from 1-50 miles before it does it again. Except for last night we had to crank on it for about 3 or 4 separate times before it started back up. If it was a short it would not have cranked would it? Is there anyway to test the icm when it is just a random problem or does it just need to be drove till it brakes?

 

[Fuel Fire Desire]

mine has always restarted right away and was able to be drove for anywhere from 1-50 miles before it does it again. Except for last night we had to crank on it for about 3 or 4 separate times before it started back up. If it was a short it would not have cranked would it? Is there anyway to test the icm when it is just a random problem or does it just need to be drove till it brakes?

With my issue, the short would only last for a fraction of a second, but it would be enough to starve the ECU and engine of electrical power for it to stop firing and shut off. Most of the time it occurred in rain or snow.

 

[Spudy]

tomorrow i will go through it and look for anything like that. It is just wierd. I wish the damned thing would just brake so i could fix it.

 

[Haggar]

Can you get a fuel pressure gage on it, that you can monitor while its driving?

Or else, you can run a wire to the fuel pump power lead after the relays and resistor. The, monitor the voltage on that line as you drive and see if its cutting out.

 

[Spudy]

but with it not sputtering or anything right before it dies could it still be a fuel problem?

 

[Haggar]

Dunno, I haven't expereinced it myself. He says his just cuts out like the key was turned off.

 

[whyme86]

check the battery term, they could be loose or fucked up

 

[Denton]

I had a problem like this and it was the damn battery. It was not secured properly and everytime I hit a big bump or accelerated fast, the battery leads would make contact with metal causing a short.

 

[Haggar]

It just seems its something pretty common specifically with grand prixs. When you type in fuel pump grand prix on google, it'll suggest resistor, so its something everyone is searching on...

 

[mudman17]

mass airflow sensor it just happened to me take it off and clean it

 

[blownexploder94]

had similar issue with a 3400 and it was the 24x crank sensor would cut out. watching it on the scan tool it would read all over then freeze then go blank once and a while. but the 7x crank sensor stayed reading fine

 

[Haggar]

I talked to my buddy at work, he confirmed his was the resistor. He said its hard to get at, he let his old one there, pulled the wires and placed the new one in a new location. Good as new.