I put the 400 in my 79 Bronco that was in my 77 F150. In the truck, it would usually turn over as long as the key was held to start, but wouldn't fire until the key was released to the RUN position. I tried new ignition switch first, becasue it seemed the most obvious. I don't recall where all my work with the problem led me, becasue the starter got stuck one of the times that it did start correctly and broke the bell housing. That's what cued me to pull the engine. It was the best way to replace the bell housing, which I had no plan to do anyway because the truck was a beater. Has been the whole 12 years I've owned it. It's been a great one, but ugly and beat to hell and back.

My plan the whole time was to eventually put it in the Bronco, which had a known bad engine. Knocking, smoking, the works.

Now the Bronco has the problem. Sure the old engine knocked and smoked, but at least it started hassle-free.

Can I get a concurrence that the ignition module could cause this? I used the one that was in the truck, because I knew its history. I bought it a few years back (ok, probably 8 or so) and assumed it was fine. After all, it even looks newer than the one that was in the Bronco....ha ha.

I don't want to go buy a new one without knowing the likelihood that it's the problem.

 

This is one of the failure modes of a ignition module. Try another one.

 

excellent. I looked and they are 65 bucks. 19.99 for a cheapo.

 

Do you have a junkyard near? You might be able to find a Motorcraft one. One from a Lincoln, Ford, Mercury, car or truck, any number of cylinders, will work so long as the grommet where the wires go in are the same color.

 

Oddly, I had one hanging from a hook behind some other stuff in the shop. Says WELLS on it and looks brand new, same color grommet. I don't know how long I've had it or why I have it, but I'm cool with it.

The Bronco starts great now.