I have limited knowledge of diesel engines, so please forgive my ignorance.

I have a 1992 GMC Vandura G 3500 with a 6.2L engine. The vehicle was acquired with only 52k miles on it. It was owned by the Harbor Patrol and probably sat more often than it got driven. I bought it two years ago and have been using it to pull an asphalt sealcoating rig.

I live in Northeast Ohio where the truck sits outside all winter. I make a point of starting it every 6 weeks or so when not in use. Until recently, it has run very well.

The first time I had trouble was when I picked it up from a graphics installer. The truck started as usual. It idled fine while I let it warm up. After getting about 500 ft. down the road, with my foot still on the accelerator, it completely died. No hesitation or sputtering. It just cut out. I was able to restart it and get it back to the parking lot. A friend recommended pouring a product called "heet" in the tank and adding some fuel. After doing this, it started right back up. It idled fine and i was able to rev the engine without any problems. I tried once again to head out, only this time up a hill and it stalled in the same fashion. Only this time, it would not start again.

I had the truck towed to a diesel shop where the mechanic said the fuel filter contained a lot of water. He replaced the filter and took a fuel sample, stating that the fuel looked good. He returned the truck after a few test drives and said it ran like a champ. He was right at the time.

I hooked the trailer up a couple days ago and headed out. Everything was running fine. Up and down hills, freeway travel at 65 MPH, no problems. Then, I left the truck running at idle in the supply yard for about 40 min. After leaving, I got out on the road about a quarter mile and started up a hill and the same thing happened. The engine stalled without warning.

One thing I forgot to mention is that the engine got hot one time when I was driving. I was close to home and got there and parked it. I let it get completely cool and added to the coolant which was pretty low. Seeing as though this was prior to the stalling, could there be a relationship? If not, does anyone have any ideas?

I don't mean to write a novel here. I just wanted to give as much information as possible, in order to get the best guesses. Thanks in advance for your help.

 

Did it restart after pouring in the coolant??

 

Yes. I started it and drove it to the graphics installer where it sat for a few days.

 

yeah thats my question too. also check your fuel filter again to see if water got into it again. also do the 2000 RPM test. slowly rev the engine to 2000 rpm and hold it there for 5 seconds. then slowly let it back to idle. if you do this smoothly with no surging or missing your IP should be good. if it cant the IP is probably on its way out

 

It could be a bad torque converter.

 

Can you explain the relationship of a bad torque converter to my problem?

The shop where the vehicle was towed (owned by the tow company) claims to service diesels. They called today and said the truck is up and running. They figure the problem was a loose alternator belt. They said that when they got around to looking at the truck, the battery was dead. I believe this was because the ignition was left on when the vehicle was shifted to neutral for towing. I also turned the hazzards on as a precaution and asked the driver to turn everything off when he gotr to the lot. He probably did not. Besides, after stalling, the engine turned over strong several times and there were no signs of a drained battery.
These guys also claim to have taken a fuel sample which they say looked good.

So far, I know that the stalling only occurs when the vehicle is in motion and unless it's coincidence, going uphill may be a factor. Does this point to anything?

 

While poor gnds are not as critical to 6.2 as to the 6.5 EFI, the gnds are important to keep voltage up for charging and accessories, one of which is the fuel shutdown solenoid on the IP it needs constant 12V to keep it open whle truck is on, also ignition switch known bad actors, same thing no 12v out of them no power to fuel shutdown solenoid.

IIRC mechanical fuel lift pump on this, if diphragm in it no assist to get fuel to IP or puts air into the IP which will kill it also.

I have no idea how torque converter would play into this scenario

 

How sensitive is that solenoid to voltage? If the volts were to drop to say 11, would that be enough to cause a shutdown?

 

Seems more likely it's not a voltage problem but a bad wire leading to your fuel shutoff solenoid as said by turbine doc. Also comment bad key is correct, this has happened to me, both a bad key lock, and a bad wire down to the starter (where it gets the juice) from the key lock, stops the whole truck cold. The wire going to the starter goes right by the exhaust and takes a lot of abuse just inches above the road. Check these wires first with a test lamp before doing any expensive fuel pump/injector work. Jiggle them and you will likely find a connection that is just barely hanging on. Also make sure your battery terminal connections and grounds are strong. I added a cheap thick ground strap from my block to the body just to be sure, the glow plugs alone will want to flow a lot of amps through your block. Your suspicion about the tow truck driver leaving the power on and draining the battery is probable, if it was cranking strong after the last stalls it does not sound like a charging problem. Juice being cut to the fuel cutoff solenoid will kill the engine immediately, there will be no sputtering or loss of power to warn you. If your truck is dying like that then voltage to the solenoid is the most obvious candidate.

 

could it not be your fuel pump driver. we have had a problem like this with a truck when it got hot it would just quite.