It’s been quite a while since I messed with an IDI van, so I can’t recall how easy the filer head is to get to. But if you can get to the schrader valve on it, you can reprime the fuel system with a hand held vacuum pump like this.
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They are fairly inexpensive. The fitting that screws onto the schrader valve is the only special part. This one was scavenged off of a tire valve stem extension hose, but the end off a can of fix a flat will work to. Just thread it onto the schrader valve and pump until you get clean fuel with no air into the hose. You may have to stop and empty the cup a time or two. Once the air is out, just remove everything and start the truck should only take a couple seconds of cranking.
About 20 years ago, I was working for a company in Knoxville. One of the crews had a 90 or 91 e350. They ran out of fuel in the middle lane of I-40 at 4:30 in the afternoon. They called me, and luckily i wasn’t far away and I had a gas can in my truck. I stopped by the gas station and filled it up with diesel, then made my way through traffic to them. We dumped 5 gallons in the van, but saved a little bit to fill up an empty windex bottle I had. I had already had them pull the dog house off, and I removed the air cleaner. I started cranking,and spraying diesel mist into the intake. It was a trick an old timer had taught me. It worked (though I probably wouldn’t recommend it now), and I was so relieved when that ******* roared to life. They drove the van the rest of the way to the shop with the dog house off.