One of my trucks is a 1989 F250 5.8L, and ever since I have owned the truck it has left me or one of my employees stranded, seemingly whenever it feels like it. I have had the truck into the local ford dealer and to other small shops numerous times.

Things I know...It seems to stall on a day when it suddenly gets warmer. ie a week of 50deg and then a quick jump to say 75 or 80 deg. Even though the truck will run most of the summer in 95 plus deg. when it does stall it will NOT restart for approximately 2-3hrs. It does have spark during this time, I have checked it. It has a single gas tank and I think it has the setup where there is a pump in the tank and a pump along the line. Both have been replaced. The only other weird thing about the truck is that it is hard to fill with gas. the gas will bubble up the line if you try to fill it at a normal pace. there is no kink in the line, or the line inside of the line. The timing has been checked and rechecked and the ignition module has been replaced about 5 TIMES!

I have also read on here about a possiblility of the gas boiling in the lines causing air in the line. That could be a possiblility but the whole line has intact insulation on it as soon as it nears the engine compartment all the way until it reaches the top of the back of the motor. There is about a 1' section of exposed fuel lines, both of them I think at that location. Could this be the area of extreme heat causing this problem. Any ideas or anyone with experience with this, chime in, this has been very costly and very annoying. Thanks Glenn

 

I would start carrying around a fuel pressure gauge and check the pressure when it dies. That will at least rule out the fuel system. That section of exposed steel line shouldn't cause a problem, they're all like that.

All the engine needs is fuel, spark, and air to run. If you're sure you've eliminated spark, and air is more or less a given, then it looks fuel related.

I would also learn how to check the codes. Check them when it's running fine so you get a good baseline (this is also a good time to fix any problems that the codes indicate ) and then check them again when it acts up. You may have a sensor that acts up on occasion.

Codes: http://www.broncodata.com/tech/codes.htm

 

I would do exactly what Andy
said above that should be a rather easy problem to troubleshoot. things to check would be when it quits can you still here the fuel pumps running and do they sound normal. also check the inertia switch reset it and if you can Chang it with another truck and then the other truck starts having the probablem then you know what is up. with what you have been through with that truck I would have mounted a fuel presher gage under the hood.

 

I would replace the gas cap. It's cheap, easy, and could be the problem. If air can not get in to the tank, fuel flow stops.

 

If yes you have a bad EEC Computer or fuel pump relay, they should stop when the engine stops. If it was tripped you would not be able to start it later You would have bad contacts in the switch.

You may also be getting bad information to the EEC Computer from the TFI/Pickup coil in the distributor, this could be a bad pickup coil or wiring back to the EEC Computer.

And yes do what Andy said above.

 

a couple of months ago I was working on a truck that was doing the same as yours and after much troubleshooting I found that the inertia switch was intermittently callusing the pumps to shut off. I replaced it and the truck was fine. any component can go bad. and assuming in automotive troubleshooting will cost you a lot of time.

 

Now I have a few things I can try. I remember i used to know where the inertia switch was but one time when it did stall and leave my guys stranded I tried to find it and check it. I remember I gave up looking when I turned the key and heard the fuel pump prime or whatever it is doing.

 

Here is a diagram of the inertia switch location.
http://i54.photobucket.com/albums/g9...SwLocation.gif