2000 F250 no start when hot

My 1995 F250 does similar with the FRONT gas tank. It has been diagnosed as "vapor lock" but I am not convinced that is the complete problem. In my case, I just switch to the rear gas tank, then after it runs for a minute, I can just switch back to the front tank, or continue using the rear. To me, it is aggravating, and I have to remember to NEVER run the rear tank to empty. If you have 2 gas tanks, give it a try. If you only have one, maybe vapor lock is a starting point in solving your problem.

Good luck with it, and please report back

" Joe" wrote in news:i078d2$e0o$ snipped-for-privacy@speranza.aioe.org:

I've got one 40 gallon tank, so I can't try use tank switching trick. Vapor lock sounds like it could be the problem. Maybe some insulation around the fuel lines or just a simple adjustment in their routing. I'll report back as I solve this problem.

Thanks.

Does Ford use an accumulator in the fuel lines? VWs used to have those, and they'd occasionally be hard to start in hot weather when they went bad. Another symptom would be cutting out on hard corners with low fuel level. (had an '84 GTI that did this; it was exacerbated by a rotted plastic pickup tube in the tank to the point where it would cut out on a corner with anything less than 3/4 of a tank. I ended up replacing the fuel tank with one from a Jetta, which being made in Germany apparently used a different pickup tube that was more durable.)

nate

Vapor lock happened when the fuel pump was a mechanical device located inside of the engine and had to suck fuel from the tank.

I don't think it's possible to vapor lock a fuel delivery system where the fuel pump is phisically located inside the gas tank and pushes the fuel at something approaching 60psi to the engine.

I suspect your issue is a failing fuel pump itself.

The pump is submerged in gasoline, and this is supposed to help keep it cool, but gasoline is also a drying agent and it cuts any lubricant there might be. The bottom line is that the fuel pump lives in a harsh environment and is prone to failure over time. I suspect your pump is dragging when it works, and eventually drags to a stop, or nearly a stop. The result being very low fuel pressure resulting in very poor power response.

This makes sense, but it is intermitent and it started just as Louisville, KY went into daily temps in the high 90s. The engine has never quit while it's running, just won't restart after it has been parked hot for a few minutes. And, once it has a chance to cool down, it has always started. Could a sensor be going bad due to the heat?

Ford does use a fuel pressure regulator but I don't see an accumulator shown in the shop manual.

On Sun, 27 Jun 2010 18:12:39 -0500, Peter W Crisler rearranged some electrons to say:

All the speculation about fuel pumps can be put to rest by simply putting a fuel pressure gauge on the rail during this no-start condition. If there is sufficient fuel pressure (i.e. 40-60 psi) the problem is not the fuel pump.

heat soak conditions.

Yes, very possibly.

Try (carefully/discretely) with a spray bottle of water soaking down things like the fuel lines near the engine, and see if that helps.

Also, look for missing heat shields. This truck is getting old enough that the exhaust heat shields could be falling off allowing places to get hotter than they normally should.

I'll try this the next time it won't start.

I looked the engine over pretty good Sunday and didn't find anything missing or evidence of any rusty tabs of lost shields still under bolt heads. And the fuel ines are clean, not covered with any grease, grit or oil. And they are not touching the block or transmission. I'm still working on it.

I'll start packing my fuel pressure gage with me.

Can't you just screw it onto the schrader valve and leave it there?

"Jeff Strickland" wrote in news:i0d41g$k2q$1 @news.eternal-september.org:

I guess I could, but right now I am working 6 days a week and just don't have a lot of time to do my own diagnosis and testing. And I need the truck. So, I took it to a very reputable shop and should hear something tomorrow.