on my 86 bronco with the 4.9l i have the ignition system(duraspark 2) i think, what ever ford switched to in the later years.

but i went trhough one coil which i took out of my 93 f150 and it ran for 6 months then died when i floored it in 3rd and just shut off on me and would only start when it wants to, so i replaced it with the original one that came with the bronco when i bought it, then i did a little mudding and it was running a little like crap then the next day it died in the exact same spot when the first coil went.

so i stuck my MSD one i had on my 93 f150 4.9l and it ran good. i had a couple issues when i was driving it where it would die when i was going down the highway, so then today im driving it and it completly died on my and wouldnt start back up, then i pop the hood to have my friend watch for spark and i poped the coil wire off and happend to set it back next tot he main terminal on the distributor and when i turned it over it started up then ran for a couple seconds then died..


what would be causing the coil to im guessing heat up and lock up where it wont start until it cools down where it will start agian? and run only so long.


now i went to autozone and bought 2 coils so i would have spares with warranties, but i installed one and drove home from my friends house about 10 miles away and when i was pulling into my driveway i notices the RPM guage jumping around like it wanted to die.

 

Ok assuming here with you saying its Dura Spark igniton you have a 2 connector blue grommet ignition module. I would be more suspecious of the module than the coil. Have you check for out put to coil from module yet? That era of ignition was very prone to shutting down and if you let them cool off they would start and run again. I used to replace lots of those modules and very seldom a coil.

 

Very likely at was stated above your DS2 Module is overheating. Unbolt it and look for bubbles in the plastic/wax material on the underside. If none, remount using 1/4 inch or so standoffs. It helps to improve airflow. Also I would personally carry a spare module, coil, alternator, starter, solenoid, but that is because I drive way out in the sticks...

 

k i will take a look at that today. lol i hate i posted it uder f150 not bronco. well it was late a night.

 

Bronco is ok here, it's the same truck as ours in this generation anyways. This F Series forum will get you the FASTEST (and nearly the best) help than almost any other forum on the board.

notice all the disclaimers. need to keep everyone happy....

 

now the other question i have is, why could it be the ignition modual when i replace the coil the truck runs fine?

i did have to replace thhe modual in Nov. when i bought the truck because it wouldnt start. i had it cecked when thhe first coil went on me and it was good.

i will take it off again and get it checked. this time at 3 different auto stores.

could i possibly re-locate the coil to some place where it will stay cool? or would i loose voltage for the spark with a long spark plug wire?

 

It's worth checking the wiring connector that plugs into the coil. Also check the wires that run from the coil to the DS2 box, that whole harness. I had a loose wire at the coil once and it caused my truck to run horribly. It was where an old wire splice had broken loose over the years.

I swapped in another coil harness and it fixed the problem completely. (Swapping the harness is easy, it just unplugs; alternatively you could just repair your existing harness.)

FWIW I have an old Motorcraft DS2 module with at least 75% of the epoxy melted out, and it still works fine...LOL

 

Make sure what ignition system you have.

In 1984 Ford switched from DS-II to the EEC-IV/TFI-IV ignition system.

If your truck/bronco is stock, then you have a EEC-IV/TFI-IV ignition system.

If you have a DS-II system. Large metalic box on the drivers side fender, with a blue wire grommet, then it's been swapped out.

These two systems use two seperate ignition coils. Also the DS-II system requires a resistor wire for it's coil. If the ignition system is a DS-II system, then using a TFI-IV coil out of a 1984-1996 could be your problem. If you are using a DS-II coil, not having a resistor could be your problem.

The TFI-IV system are notorious for going bad due to heat, as the module is hooked directly to the distributor.

 

Did I hear you say that the coil was hot, or are you just presuming it was hot? I have had a similar problem lately, and I think I have it narrowed down to some electrical connection between the coil and the dizzy (and possibly the module). I changed my coil last week, and it still died on me a couple times the next morning. When I messed with the coil connectors and the middle dizzy connection, that seems to clear the problem for now. I went out and got another coil connector just in case the problem resurfaces and theres an issue where those 2 wires go into it. It took a long time to narrow this down, and I've replaced several electrical components under the hood trying to fix it.

 

well i was on my way home from work today and it started to sputter andthen died, so i pulled into an empty parking lot to change out the coil quick, well the coil wasnt the problem this time, i had the ignition modual tested quick and it is good. then i was thinking about a buddies chevy blazer i had to fix. his pickup in the distributor went bad so it ran when it wanted, when it heated up it died, when it cooled down it would start and run for so long.

this time when i tried to start the bronco it had no spark at all, so i had a friend trailer the truck home to work on it quick, the part is only $18, so i got one and i wont find out if it is the problem yet because when i was putting the distributor drive gear back on some teeth cracked, so i have to order one.



my ignition system i have is EEC-IV/TF-IV, the igntion control modual is mmounted on the side of the distributor

 

ok better information now its amazing when wanting help to give up the whole picture. ok early TFI units were very prone to pick up failure of the insulation / grommet on the pick up where the module connected to it. In my shop if I have a module fail on a TIF system it automatically meant the pick up got replaced at same time due to frequent failures of them.

 

FYI the distributor drive gears are availabe thru NAPA part number DG307

 

yeah every place had to order one. i have to wait till i get paid to get a gear. i got a question now, on the distributor their is this little rod that helps hold the pickup on, can you loosen the screw up and adjust that pick up or something? i will see if i can get a picture of it

 

That is called an octane rod it is a non adjustable item. In all my years of working on Fords never really questioned if you could get another one or exact purpose of it.

 

Also make sure to smear some dielectric grease on the back of the ignition module before you bolt it back up to your distributor. The grease is essential to keeping the TFI ignition module cool!