hey guys i need a little help here this is my first ford i like it alot but it keeps diying at the most inconvient places like in the middle of an intersection! i bought at auction i know nothing about the history of it. its a 1985 f250 been rebuilt it has an edlebrock 4 barrel theres a switch to a fuel pump located on the frame i dont know why its there cause i drove for a month without swtiching the pump "on" so that has me a little confused but lately i will be driving normal and at 10mph or 60mph it will just die after 20 min start up cold or if ive been driving all day i cant figure out why it does it but 2 months ago i could pop it in N and crank and she will come alive again now i have to pull over and wait 10-15 min. it will crank and crank but nothing. anyways if anyone has any info i would love to hear it. im not familiar with carbureted motors im usually messn with efi motors but i would love to get this fixed.

 

Does your distributor have a gray module on the side (the TFI module)? This is a possible culprit, and there was a class-action lawsuit against Ford due to this part failing while in traffic.

It could also be a temperature-related open circuit in the pickup coil inside the distributor - mine did this after running 20-30 minutes, and it would restart after sitting for awhile.

When it stops running, pull a spark plug wire and use a screwdriver in the plug boot held 1/8" away from grounded metal on the engine, have somebody crank it over, and see if you have spark.

The frustrating thing about this kind of failure is that you have to make some educated guesses, and then check for them WHILE the failure is present.

 

If it's not the TFI module, then it's the other type...mounts on the left fender inner apron.

The three step scenario of a failing DuraSpark ignition module:

1) Module overheats, engine dies. Module cools down, engine restarts almost at once.

2) Module overheats, engine dies. Module cools down, engine restarts in an hour...or so.

3) Sooner or later, usually sooner...the module overheats, BURNS OUT. Now the engine will not restart.

Engine heat, especially on V8's that radiates from the red hot left exhaust manifold is the mortal enemy of these modules.

If replacing it, use some washers to space it further away from the apron...the more airflow around the little charmer...the better.
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TFI lawsuit = Ford lost. About ten years ago, the NHTSA forced Ford to recall FIVE MILLION vehicles to replace this terd:

E43Z-12A297-A .. TFI module (Motorcraft DY-425) / Marked: E3EF-12A297-A1A or A2A

Mounts to the dizzy with Torx headed screws. A Torx driver with a thin shank is necessary to R&R it.

This module will be found, beginning in 1983 on myriad: Passenger Cars, Trucks, Bronco's, Econolines and etc. It was a POS from day one!