my 79 f-150 will start and run fine for 10 or 15 minutes then it dies. i have found that it stops firing. i have replaced the coil and put 3 new brainboxes on it. nothing helps. please help me i need thie truck for the winter.

 

mabye wire going to the coil wearing out? getting hot and failing? i would run a temp wire and see if it helps.

 

i will be making a list of possible solutions to carry with me next time i visit my truck in South Carolina as i have moved to West Virginia leaving it at a friends house till i can keep it running well enough to make the trip. anything you can think of will help. thanks again.

 

If you have voltage to the coil + and also to the red wire going to the module, but still have no spark, and modules didn't fix it, I would try replacing the pickup inside the distributor. This is a little bit of a job, so you can decide if you would rather replace the pickup, or replace the whole dist.

Here's some info, though some of these tests probably will not work being you have a heat related problem.

http://www.autozone.com/az/cds/en_us...rInfoPages.htm

 

Will a distributor from a 78 351M work in the 460?

 

Yes. If I remember correctly, the dist in a 351m, 400, and 460 are the same. All you have to do to verify this is to look up a new dist online from someplace like Online Auto Parts and Auto Accessories Store at PartsAmerica.com or even a hotrod type dist from jegs or summit, and find out of the part number is the same.

 

Could the selonoid switch cause this problem?

 

If the motor is cranking while you turn the key to start, and stops cranking when you take the key off start, then the solenoid is fine.

 

Yes, the solenoid has nothing to do with the ignition. You said in your first post "it stops firing", so I assumed you had checked for spark and had none. Is this correct?

 

yes i pulled the coil wire off then cranked it and had nothing. when it works the big blue spark comes out of the coil. just mentioned the solenoid switch cause a guy at work said his 77 f-250 with same motor did the same thing. he changed it and his problem was solved. i did not think it had anything to do other than at startup. maybe he moved a bad connection in his efforts that actually solved his problem. but im entertaining all ideas at present. another guy agrees with the pickup coil in the distributer being the culprit.

 

BTW a quick check at autozone says the distributors are the same for the 351m and 460

 

after all the trouble Franklin2 was correct. it was the module in the distributer. about $29 and 20 minutes was what it took to fix it. drove it the 350 miles miles home. thanks everyone for your advice!!!