Hi Big Toe,
The fire started in the HVAC system. It caught on fire as I was driving it down the highway. Was probably on fire for a couple miles, before I realized it. All the smoke was going down and under the truck. No signs of fire could be seen from the cab while I was driving. I saw the smoke when the engine started losing power and I looked in the mirrors before pulling it off the road. The AC/heater box in front of the firewall was the primary area I saw in flames when I first opened the hood.
I have a theory about how it may have started. Don't really know if it's right. I was running the AC that day. It was 117 degrees and about 4 in the afternoon when this all went down.
I think the large resistor for the AC system, which is either inside or attached to the heater box, failed or shorted out and burned up, which probably lit some leaves/pods afire that a rat had likely packed into the heater box area. We have packrats out here. They ate up the injector wiring on my other gas engine F350 about a year before the diesel F350 burned down.
There was a massive electrical short going on, as the whole wiring harness under the hood was smoldering at the same time the heater box was afire. By the time I stopped, the heater box had already lit the plastic inner fender well on fire, which soon collapsed onto the tire and lit the tire on fire. It was a gonner from there.
I had 3 fire extinguishers on the truck. None of them worked. 2 must have had leaking pressure valves, as they were full of retardant, but there was no pressure to shoot it out with. The other, I think I had used partially awhile earlier and forgot to have it refilled.
If I could have quickly disconnected the batteries, and had at least 2 working fire extinguishers, I may have been able to save the truck. Every vehicle I own now has working fire extinguishers, 4 for the new truck. I added battery quick disconnects to all my vehicles too, except the International, which I haven't found a disconnect for yet that is big enough to handle it's 3 giant batteries.
That is a healthier increase in horsepower than I had thought for the newer 7.3 trucks.
I probably have the wrong term when I said turbo waste gate. It may very well be called exhaust back pressure valve. Anyhow, it worked alright. The programming is apparently a common upgrade modification for 7.3 Powerstrokes. My transmission guy did the modification at the time he rebuilt and reprogrammed the E4OD tranny.
