1992 Dodge W-150 Starting Problem after Driving

[Jim44]

I've got a '92 Dodge Ram W-150, Magnum 5.2L Engine, 5-Speed Tranny w/ 51000 miles on it in pristine condition. The engine runs cool (normal) even on hot days but 4 times now when I've been pulling a heavy trailer and working this engine or just the other day, driving 100 miles in 100°+ temps, after shutting it off, like at a gas station to fuel up, It won't start until it has cooled way down, usually like overnight! It can't be a vapor-locked carburator because of the injectors but it sure acts like that is the problem to me. I keep thinking maybe my gas-line past the exhaust manifolds is getting too hot and doing some sort of vapor-thing. It's driving me nuts and I'm getting gunshy. I just replaced the gas filter in the frame so I know that ain't the problem and I did replace a Coil that went bad a while back but other than that this rig has always run good. Any ideas would really be appreciated. Thanks, Jim.

[BernieB]

I think you're right that it's heat related, and that something is getting heat soaked when you shut it down, and not coming back until it cools again. The two most common problems of this type are vapor lock and hot coils. I'm assuming it cranks, just won't start, so it's an easy matter to see if you still have spark when the problem happens. If you do, start checking fuel lines where they pass close to any heat source. I'd suggest getting a 2 gallon (or bigger) garden sprayer filled with water and just start hosing down suspect areas to cool them, then seeing if it starts. Once you find the problem, if it's vapor lock, you'll probably want to try a heat shield or rerouting the line.