I have had this truck for a year. It runs like a champ. I tow junk cars to the shredder. I pull a 5th wheel camper, an Econoline 10 Ton Equipment Trailer modified to carry two cars, and a 5 Ton Lowboy (35' long) I've gone across the scale (at the shredder) with 22,000 lbs. It walks the PA mountains with that camper with no strain. This truck runs great!
One day it shut down, as if it ran out of fuel, but the gauge read HALF. A check revealed a bad sender on the AUX tank, with holes and rotted tubing and a total mess. It was full but when the front tank called for fuel the AUX would have none of it and then the front tank ran bone dry.
I've owned three other diesel tow trucks but bought each one new so I didn't work on them when they needed repairs. I'm totally uninitiated where diesels are concerned. I'm retired now and we closed down the junkyard but I still have this equipment. I need to get it (the truck and the two trailers) all cleaned up and sell them. In my ignorance, I "figured" I could make a ONE-TANK truck out of a TWO-TANK truck. Then I could take my time and try to locate a whole setup from a junkyard as long as it was in good shape. The first place they towed me to wanted to put in a new tank ($900) and sender ($575) with $99 per hour labor. I can't afford this. I'm ALREADY buried in this equipment to where I'll NEVER get my money out of it!
I disconnected the hoses between the tanks. I unplugged the pump between the tanks. I filled the front tank and after a lot of cranking, it started. The garage charged me for changing the fuel filter, so I knew that was clear. I could see inside the tanks and they were clean and the fuel looked okay. I did crank the heck out of it, bleeding the air release on the top of the filter repeatedly. It appeared as though I had been successful.
I drove it on the highway for about 100 miles over a three-day period. It ran fine, as usual. Then one day it shut off.
I suspected it had run out of fuel again, but it shouldn't have, since I had filled the front tank and only driven about 100 miles. I pulled the filler hose off and I could see fuel in the tank. I put another 5 gallons in thinking it might be below the take-up level, or something (I don't know)
I cranked and cranked it and it got to a point where it was starting right-up but then dying when I released the starter (ignition switch)
I kept trying and trying because I was certain that it had somehow run out of fuel again. One time I hit it and it started up just like nothing was wrong. This truck usually jumps-alive, with only the slightest cranking, even thru the winter months. There was no rough idling or bad running or anything that seemed wrong. I thought I had gotten lucky again! I set out to drive it home. After about a mile, it shut off again, and I had to call AAA to tow it home.
I read a post that said that starting then stalling is a common problem with GM 6.5 Turbos. It said that if a certain DTC wasn't present then it was a 95% certainty that the PMD was bad. Now mind you, I didn't even know what all these acronyms stood-for before this event.
I went to Harbor Freight and bought an OBDII Reader. It showed a P0126 & P0236 DTC, neither of which was mentioned as relating to this problem. I ordered a Remote PMD Kit ($407 with the shipping) and the truck started and ran. I drove it to work for a whole week then on the weekend it shut off while I was driving down the road.
I seem to have really compounded my problem by running on the main fuel tank, making it very difficult to apply "the scientific method" in troubleshooting the problem. The AUX tank still has the rotted-out sender in it but it's not connected by hoses to the main tank.
Someone said I still need to have the AUX sender connected electrically, so I put the plugs back on (but the hoses are still disconnected)
I've been reading about GROUNDS and TESTS I need to perform, but I've come to the conclusion that I'm going to have to buy a new sender and hook it all back-up before I can check for any other faults. Please excuse my rambling but i am at wits-end with this darn thing!