I just bought a 1975 F250 4WD, the previous owner said it was a 390 but I don't know how to tell what it is. I drove it home just fine and took my wife for a little ride, but about 5-6 miles into the ride when I was slowing down to a red light the engine just quit on me. When I tried to start it up again it would turn over, but wouldn't fire up. We pushed it to the side and towed it home, I tried it again and it fired right up (about 30-45 minutes later). I'm by no means a mechanic, so I did the basic replacement of the air filter, fuel filter, spark plugs and checked the fuel pump. I took it around the block to see how it would do and it died right as I was pulling into my driveway, and it wouldn't start again. Left it for an hour and it started right up. Any suggestions on where to start looking?

 

your ignition control module is going.

 

That's a textbook example of ignition control module failure, they overheat and shut down, let them cool for an hour and they fire right back up, i carry a spare ICM under my seat.

 

damn....i had the same problem, people on here and a mechanic told me it was my carb, so i bought a carb, but havent installed it yet. I guess i will be checking my ignition mod....that sucks

 

I'm not convinced it's the ignition module yet; usually they just cut out completely, and it takes less than 30 minutes to cool down enough to start.

Next time it dies and won't start, connect a test light from the TACH TEST terminal of the coil to clean, unpainted metal on the engine (ground). Keep the coil connected. Crank the motor over with the key, and the light should BLINK. Report your results. If the light BLINKS yet it does not start, then the ignition module is not the issue. If the light stays OFF or stays ON, then it's ignition-related, but not necessarily the module. We'll go from there.

 

I also AM not convinced it's the ignition module. Yesterday I posted a stalling problem very similiar to yours. Get a can of starter fluid and when this happens next time spray some down carb andsee if it runs then stops. That would tell you it is a fuel problem. When my truck stalled I swapped out a spare module with no results then a spare coil with no results-although I have confirmed spark is good before swapping parts. Starter fluid makes it run briefly. If I let is sit it will run again. Installed a new fuel pump but still have stalling issue. I see gas in carb when I pump the throttle so I'm really at a loss too. Could it be the oxygenated fuel?

 

Could be vapor locking..................Look for fuel lines routed too close to the exhaust.........

 

Okay, well I have a new ICM on it's way, should be here on tuesday. I'll grab a test light tomorrow (Sunday in Utah, everything is closed). I have tried the starter fluid before with no results, which made me think it wasn't fuel related, but could be wrong. I checked fuel lines and they don't come too close to the exhaust, but I tried to test for vapor lock. I don't know how to test for it, so I decided to just leave it idling. It idled good around 1200 RPM's for about 3 minutes, then started dropping making a rough idle. 5 minutes into the idle it died, acting like before not being able to fire it back up. Thanks for the quick responses, let me know if you guys need anymore info, pictures, etc...

 

Went through this within the last couple months myself. Thought it was the ICM replaced that, still was doing the same thing. Was just about to throw a bunch of parts at it, and decided to take it to a garage. They said it was the fuel pump. I tried many of the previously posted tests for the coil and stuff, but still couldn't pin it down. Figured it'd be easier to let a shop figure out the problem for me. They replaced the fuel pump adjusted the float in the carb which I had rebuilt, and it ran fine. That is until the inline fuel filter that a PO installed became completely clogged. Got that replaced too, and no more problems...yet. Oh another thing. If it has locking gas caps, and it's not vented well, every once in a while, loosen the caps to reduce the pressure inside the tank. I did that the last time it died on me, this was before I got the inline filter replaced, and it ran long enough for me to get back home. Good luck.

 

Finally my ICM got here yesterday installed it, and it's running great. Haven't had any trouble with it so far. Thanks everyone now it's time to replace the clutch...

 

I had the same thing happen to me not that long ago. Did all the tests, figured out it was a fuel problem. Changed the filter and pump, still would randomly die on me. So I decided that it was time for me to rebuild my first carb. I had been told that my 2-barrel motorcraft carb was about the easiest carb in the world to rebuild, and I found a guy on youtube who filmed a full rebuild, while chugging beer the whole time, how hard could it be then, right? So I went to the wrecking yard and found a rebuild candidate that had a matching tag number. Got a rebuild kit and cleaners from the parts house, and off we went. While taking this new carb apart, I found a small internal screen filter!!! It's under the needle valve, by the input that the fuel filter screws into. Son of a b*tch! So I ran out to my truck, pulled the top off the carb, pulled the float out, unscrewed that brass fitting in the fuel bowl, and sure as I thought, that little screen filter was full of many years worth of junk that had made it past the screw in filter! So I cleaned it all out, and she ran like a champ. I finished the tear down, cleaning, and rebuild of the wrecking yard carb, and thing looks and operates like brand new. So I put it in a box and shelved it so I have it ready to install at a later date. All and all, I like having spare parts around, it was a nice learning opportunity, and I did not have to pull the carb off the truck, risking the chance of something breaking, for no reason. Let's all be honest, we all dread the idea of replacing parts that we know have not been removed in 30+ years. Those old nuts and bolts have grown accustomed to their rusty lives. If I have to do any kind of rebuild or fix, I try and get one from my local wrecker, and do my rebuild on that part first. If all goes well, you can replace the bad part with your freshly rebuilt park. If you break or mess up the wrecking yard part, then you now know what to NOT do, and hopefully can avoid that issue when you work on the actual part from your rig.

 

I rebuilt my carb, and I don't recall seeing that little screen in there you're talking about. Maybe different years had different things. I'm thinking my issue is the pick up tube for the sending unit inside the tank. When it's warm again, that will be another project.

 

I'm figuring out that not all carbs have them, but mine did, and a few at the wrecking yard did. It fits in the bottom of this fitting.
http://www.allfordmustangs.com/forum...b-dsc01831.jpg