1986 bronco. 1991 351w. 91 computer. Was working before changing engine due to a knock. Changed engine. It ran. Pulled out to clean up shop got in to put back in shop to put hood on and dead. No dome lights nothing. Key on nothing. Key off nothing. Key on door open nothing. Key off door open fuel injectors, pump relay, eec relay click. Turn key on back to being dead.

Sometimes can hook up battery and it works right. Try to start... back to the same problem. I've pulled the harness and checked for bad spots and fixed everything I could find. Im at a loss as to what it could be.

 

Bump

 

It sounds like you need to clean the inside of your battery cables where they hook onto the battery posts and also clean the outside of the battery posts. Then make sure the battery cables tighten down properly.

That is the most likely scenario, so try that first. If not there, the problem is somewhere with the battery cables or connections including where the ground cable hooks on the other end.

 

New battery and positive cable, the ground has been cleaned on the block and I've got a new cable I'm going to try from the block to the frame in the morning. If that doesn't fix it then I'm lost.

 

It wasn't acting up before I swapped engines is why it doesn't have a ground from block to body currently.

 

Have you checked to see if you "jump" the starter solenoid and get it to turn over/start with the key on?
If you can check the ignition switch (at the bottom of the steering column) and/or the solenoid.

 

I ended up adding a ground from the body to the battery and all is right in the universe again.