My son wanted to borrow the 1992 F-250 with the 7.3 IDI to haul his trailer of tools and materials to help a friend of his with some renovations on a rental property. No problem. I think the timing is about right from the trial and error method. Time to see how it performs with a little weight behind it. I filled the front tank and topped off the rear tank with the latest batch of B100 I got from my supplier and off he went. He pulled the trailer 325km at 120 kph with no problems. He pretty much used up the rear tank, about 65 liters. Thats 5km/l or 14 miles/imperial gallon. Not bad. After parking the trailer, he goes to move the truck to the front of the house. I get a call: "Hey dad, the truck won't start." Dohh! Good thing I gave him an extra fuel filter! After changing out the fuel filter, and a little bleed of the Schrader valve, the truck fires up. Yay! The truck gets moved to the front of the house and after a couple of beverages, he goes to leave. I get a call: "Hey dad, the truck won't start." After doing some simple tests, it looks like the Injection Pump. I know its probably not the injectors, because I just put a good set in less than a 1000 km ago. Its about midnight now, so I say leave it 'til morning, and I'll drive up with an IP. I want to drop off a couple of barrels of bio-diesel at the folks farm anyway, and its only about 50 min. further up the road. I pack up a spare lift pump, IP and my tools and head up there. The truck still won't start after sitting the night. He even tried putting in 20 liters of petro-diesel in the rear tank. The IP is swapped out about an hour after I get there. After bleeding the lines, the truck fires right up. It sounds and runs great. Sometimes you just get lucky with the timing. When its hot just a touch of the key fires it right up. Awesome. We use the truck to pick up supplies and go out for lunch. The truck is running great. I park it in back by the trailer. We decide to take a big load to the dump with it. By now the truck has sat about 2 hours. No start. WTF? I let it sit while I walk away in disgust. We find some other work to do while I figure out what I'm going to do now. My son's friend says he has a buddy that is a diesel mechanic and we could tow it to his shop where we could have a look at it. Not bloody likely! No strange hands are going to touch my trucks. About another 2 hours go by, and I have to get something out of the truck so I figure I might as well try it again. It fires right up. Hmmm...puzzling, but it works for me. I'm thinking maybe heat soak? We load the truck up with garbage that would have taken him 3 loads in his van, and take it to the "Eco Station". There is a line-up and its wait and go for a while. I'm afraid to shut off the engine at this point. We get rid of the load and decide to get something to eat. I'm not going the leave the truck running the whole time we're in the restaurant, so I shut it off. When we come out after eating, it starts, but reluctantly. It took a couple of cranks. Not just a touch of the key. All good. At this point I decide to head home. My son is going to stay another couple of days. So I fill both tanks on the truck before I go. The day he is leaving, I get a call: "Hey dad, the truck won't start." I get another call about a half hour later. "I got it started." No problems the rest of the day. He is finally ready to leave at 8:00 pm. I get a call at 9:00 pm. He is on the highway home. "Hey dad, the truck is making a lot of white smoke." My heart sinks. Not another blown head gasket. That would make 3 in about a year! "How's the temperature on the truck?" I ask. "Its good." he says. I told him to keep going and keep an eye on the temp gauge. I get a call about an hour later. "Hey dad, its still smoking, but not so bad. The temp is good. Its actually running pretty good except for the white smoke." Well thats good... The truck makes it back. I still had two barrels of biodiesel on my truck that I wanted to pump into my tidy tank. I normally pump it with my little pony pump 'til its almost empty, then pour the rest into a 5 gal. pail and pour that through a filter. When I poured the dregs of the last barrel into the pail I realized that it wasn't biodiesel. It was unprocessed, unfiltered Waste Vegetable Oil! Gack! It all comes clear now: the clogged filter, the no start, the white smoke. I picked up 5 barrels of biodiesel. Three were in white plastic barrels, two in steel drums. I didn't notice the difference because I didn't see it until I emptied the last steel barrel which is what I used to fill the 1992 F-250. So, my son brought the truck back, but it wouldn't start without a sniff of ether. If it was warm, it would start. I parked the truck behind my garage and prepared for the analysis of the damage the next day. The tailgate and bumper were covered with an oily mist. Today I tried to see if it would start. No go. I bumped the timing up a little. No go. I swapped out the injectors with a set of "remanned" injectors. No go. I set the timing back to were it was. It sputtered some. I took off the fuel filter and poured out the contents and filled it with known good biodiesel. Bing! it fired up. BTW. The injectors that I pulled out need work. The first two that I pop tested wouldn't even pop! So, lessons learned: 1. My 7.3 L engine doesn't like WVO. 2. My 7.3 L engine won't start with WVO when its cold. 3. WVO gunks up my injectors. 4. I always need to check every barrel of biodiesel I get. 5. I should get clear hoses for my pony pump. 6. Always carry a spare fuel filter. A spare lift pump is also a good idea. 7. I have so much respect for the IDI engine. 8. Humans make mistakes. Ok, I already knew that one. Hey, the other IP might still be good. There are probably more lessons here, but its late. Here's a picture for you guys: From left to right, The biodiesel I normally get. The fuel that came out of the fuel filter. The WVO that I mistakenly got.