428 electrical

[1970 f250]

I have a 1970 f250 4x4 it has a 428 cj in it. The rebuild has about 500 miles on it. It has sat for about 4 years after untarping the truck and cleaning fuel lines and putting the carb back on it. I started it. However it will only stay running with the key in the crank position. When I let off the key I lose electricity to the coil my meter says zero. If I turn the key off then back to run it shows power at the coil but as soon as I crank it and let off its almost as thought it trips a breaker. I can hold the key in crank and pull the starter off the solenoid and it stays running until I release the key to run then it dies. Is there a relay type breaker or is my solenoid bad or what the hell. Does anyone have any answers. answers.

[ted dehaan]

either the ballast resister is bad or a rodent chewed through the run wire when it was parked for so long ....ted

[jerry clayton]

Balast resistor bad???????

[jerry clayton]

so theres an 8:16 answer from Ted while I was typing my 8:17 answer------


But====how did you post a pic with less than 10 posts?

[1970 f250]

Where do I find the ballast resistor? It just let me upload it

[jerry clayton]

The ballast resistor (you do still have points ignition?) is usually mounted on the firewall but since your truck is 44 years old, it could of been moved----trace wires from the coil (mounted on front of engine near dist?) towards the ignition switch----------the deal is that the truck will start running on 12 volts but as the resistor gets warm it will reduce the run volts to aprox 6 volts to help the life of the points---------




After some recollecting?? your truck might have a resistor wire to the coil instead of a ballast ---------

[1970 f250]

No I put in a electronic module. I think its a petronix replacement for points. It eliminated the points and condenser. Yea when I testes the coil with my meter it showed 6.74 volts till I cranked the key then it dropped to zero and it resets when I turn the key off. I can send you a pic of what's on my firewall if that helps

[34_40]

Ford Pickup would have resistance wire to the coil I believe. But when you installed the Electronic Setup, did you change to regular wire?

I'm also thinking that the ignition switch needs adjusting (I can't remember if that is on the column..) or replacement, but check all the wires under the dash as a rodent very well may have had lunch with your truck! Good looking truck btw.. and welcome to the club.

ps, after re-reading your last post, I'm thinking that theres some weak connections, probably inside components like the ignition switch from being tarped for some length of time...

[1970 f250]

Its the switch mounted to the left of the column just next to the headlight switch. I can't remember replacing that wire but that's not to say I didn't I will check it out tomorrow. Thank you my dad bought that truck new in late 1969. And I put the 20 inch wheels and painted it it came stock with a 360 since 1995 I've had a 390 and about 8 years ago I built the 428 for it and just never drove it due to having a newer truck I sold the new one and want to drive this one

[1970 f250]

Oh and thanks for the welcome its great to know there's a wealth of knowledege from all the FE GURU's out there.

[jerry clayton]

I had a 1970 F250 and since we used it for a tow for our top fueler trailer, the 360 was weak but I had a Nascar 427 that I was going to change to but ran across a Lincoln 460 in a Mk2--Installed the whole package----became known as the Devil Truck---Many Ford engineers/race people saw it, talked about it, drove it and they did the 460 package starting in 1973---of course that was after the smog, low compression and retarded camshafts------------

[1970 f250]

This 428 is a better tow /hauler than my 7.3 powerstroke. Other than the modern luxuries of the new trucks this one is twice the power house that new truck was and looks a ton better. I'm running a 700 FM holley I'm curious to know my horse power.