Need GM Tech Advice 8.1 chevy

[565edge]

I need some help!!!!
I have a 2002 crew cab 2wd hd with a allison and a 8.1 motor.I have exhaust,volant air box and a westers garage computer.This truck keeps shutting off going down the highway and will turn back on before I can pull over.Sometimes it just shuts off.When it does my battery light will come on?Then it will take a few minutes of me cycling it off and on before it will start again(actually kicks over but wont run).Sometimes when I go out to the truck to start it it will turn over but will not fire?Is this a common problem. I thought it was the computer.I called Westers and they said no.But he did say if I thought it was he would replace the computer.I actually still have my stock computer and installed it and it still does the same thing. It did it 4 times today.I afraid one day its not going to start.I need help....A friend had a similar problem and his was the fuel pump?

[Daytona100]

I need some help!!!!
I have a 2002 crew cab 2wd hd with a allison and a 8.1 motor.I have exhaust,volant air box and a westers garage computer.This truck keeps shutting off going down the highway and will turn back on before I can pull over.Sometimes it just shuts off.When it does my battery light will come on?Then it will take a few minutes of me cycling it off and on before it will start again(actually kicks over but wont run).Sometimes when I go out to the truck to start it it will turn over but will not fire?Is this a common problem. I thought it was the computer.I called Westers and they said no.But he did say if I thought it was he would replace the computer.I actually still have my stock computer and installed it and it still does the same thing. It did it 4 times today.I afraid one day its not going to start.I need help....A friend had a similar problem and his was the fuel pump?
I had the same problem with my 8.1 it ended up being the crank sensor. Pretty common.

[MikeF]

It's probably just tired of pulling a boat w/a ferd in it.:crossx:

[Kachina26]

Get a code check at Autozone, you probably have a crank sensor code. If you do not have a crank code, this is one of those rare times that I would actually recommend trying it anyway. Very common on the 8.1.

[BAE_557]

I recently had the same problem with my 8.1 and it turned out to be the fuel pump, luckily it was still under warranty.

[CampbellCarl]

Did my fuel pump approx 6 months ago, problem (crank no start) came back, this time was cam sensor. Pretty cheap, around $65.00 and took about a 6 pack to install.
Carl

[24sleekenforcer]

Like K26 stated most common problem is the crank shaft sensor , it is behind left head area.

[BowTie Rick]

It's the Volant, should have got a K&N :D Actually, same EXACT thing happened to my buddies. It was the ignition switch. It would vibrate back just enough to turn itself off and being worn, it would not always fire back up.

[565edge]

So fuel pump,ignition switch or crank sensor. Where exactly is the crank sensor located? I used to carry a cam sensor around for my powerstroke.Sound like I might need to carry a extra crank sensor for this.LOL...So will it show a code for the ignition switch or the fuel pump?

[Trailer Park Casanova]

On the 8.1, the crank sensor is located behind the left (drivers side) cylinder head, and in front of the transmission bellhousing. It has a 4 wire connector coming from it, and cannot be accurately tested w/ an ohm meter. You'll get a false reading. The only accurate method is w/ a Tech-2 scanner.
If removing it, one must be very careful not to break it, or the oil pan and other internal components would have to be removed.
If you have furthur technical questions contact
Dunefreak (Pete) at:
www.dumontduneriders.com
Pete is an active GM tech, and very helpful and very good, and a good guy.

[Kachina26]

So fuel pump,ignition switch or crank sensor. Where exactly is the crank sensor located? I used to carry a cam sensor around for my powerstroke.Sound like I might need to carry a extra crank sensor for this.LOL...So will it show a code for the ignition switch or the fuel pump?
Ign sw could throw several codes as various computers will quit communicating during the fault. You could see a lean code for a fuel pump, but not necessarily.

[565edge]

OK. I located the crankshaft sensor. Do I pull out the inner fender well to R&R it?Is thier a small bolt that holds it in place. I have fat chubby fingers.Dont want to break it..Thanks for the help...

[MKE - POWER]

I agree w/ others here; crank sensor bad on my '02 8.1 also.
Question to others;
Is there a special trick to removing the plug wires in order to change the plugs on the 8.1? I have tried damn near everything, but they won't release and don't want to break a plug off.
Real question, no wise ass response please.
Thanks,

[Kachina26]

I agree w/ others here; crank sensor bad on my '02 8.1 also.
Question to others;
Is there a special trick to removing the plug wires in order to change the plugs on the 8.1? I have tried damn near everything, but they won't release and don't want to break a plug off.
Real question, no wise ass response please.
Thanks,Honestly, at 100k when the plugs are due, I sold plug wires. Partially due to time and mileage, and partially due to the fact that at least one of the eight were gonna break. The trick is to get some plug wire removers and twist them well. Most likely, you are gonna ruin at least one wire. Just get new wires and the ones that don't realease easy, break 'em off.

[565edge]

I just got back from the auto store and got a diagnostic scanner. It showed no codes?

[blackcloud75]

I had the same problem with my 8.1 it ended up being the crank sensor. Pretty common.
ditto..................on my 3/4 ton suburban w/ 8.1.....as good as new.....f'n gas hog