1977 F 250 with a 400 Cu In.

This is what I have checked:
I have power to the hot side of the coil both with ignition on and when cranking.

New ignition module.

I get a great spark upon shutting down the cranking process. One spark.
So shutting off the key collapses the primary side of the coil (low voltage) producing an excellent hi voltage spark from the coil wire. When my helper just turns the ignition key off and on I get one great spark coming from the coil each time he does that.

But it will not collapse the field while cranking. Instead there is a steady un interrupted flow of 12 volts to the coil.

Could it be the pick up coil inside the distributer aka the interrupter not interrupting the flow of electricity thus not collapsing the field?

Appreciate any input.

A/C Tech

 

My vote goes to the pick up coil. Good luck with it and let us know what you find.

 

Check the resistance between the purple and orange wires of the pickup coil, should be between 400 & 700 ohms.

 

Thanks guys. I am getting a tester for the PIP. I suspect it is not sending the signal to the module.

I will update.

 

It was the pick up coil inside the distributer not sending the signal to the ignition module. Not a big deal to change.

What is annoying is not being able to trouble shoot that specific part. I had no information on how to test it. I trouble shot every other component but was unable to verify whether the pick up coil was good or bad. So I replaced it and the truck started. Not the ideal way to make a repair.

This has been quite a learning experience for me. I'm a Chevy man so this was unfamiliar territory.

Why complicate things by having the separate Ignition Module? Shouldn't I be able to upgrade to a self contained HEI distributer? Thus eliminating that computer looking Ignition Module?

I have done that on two of my old point distributor Chevy small blocks. $89 for a complete ready to run HEI dist. from Summitt.

Thanks again for your input.

 

Every "pick-up coil" that's gone bad on me, whether it's in a Volkswagon, Chevy, Dodge, or Ford.... They all have the "exact" same results when completely failed. No spark at coil while cranking/turning engine over, and only one spark as you turn the key off after this process. Classic pick up coil failure.

 

Welcome to FTE (and )! There is a wealth of information on this site and great people willing to help.

Click on "Search this Forum", then "Advanced Search" and put HEI in the search field. You will find a gazillion threads on the switch. Also, check out:

https://www.ford-trucks.com/forums/1...then-some.html

and

https://www.ford-trucks.com/forums/1...mpilation.html