ignition modules
 

I was just wondering how the ignition modules with different numbers of pins work differently? The 4-pin modules are pretty self-explanatory (pickup coil input, output to coil), but on the other modules there's a connector wire that goes into the cab through the firewall - why?

the two are different the 5 pin is without a computer and the 7 pin is with a computer. that is computer controled . a CCC or a C4 system

The 5 pin module is for distributors with the ESC (Electronic Spark Control) system. This is the one that has the wires going through the firewall.

The ESC distributor plugs into a control module behind the glove box. All the ESC does is control spark knock. You will notice the knock sensor screwed into the block in front of the starter.

I have replaced all the mess on my truck with an MSD Pro-Billet HEI distributor.

Hope this helps,


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Mike

1985 Chevy C-10
Mike's 73-87 Chevy Pickup Site

My ESC control box is near the accelerator pedal, mounted in a free-stand-up position.
This is in the 81...