The positive side should have about 7 volts in Run and 12 in Start. There's a ballast resistor that is meant to drop it like that.

If you have spark, then are you getting it at the appropriate time? Put a timing light on it.

 

If you use a stock harness and stock setup (carb, distributor, canister coil, ignition box), you should be ready to go...assuming the truck was running before the swap.

 

The truck just ran good this morning with the old ignition while I played with the new carb to get it set up. Just double checked the timing & it should be good. Installed distributor to No. 1 TDC compression stroke. I knew about the resistor wire but I'm confused how I can get 12v with the coil unplugged and 7v plugged in. And I just discovered that I get 12v with the coil plugged in as long as the distributor is unplugged. Strange if you ask me.

 

When there's no current there is no voltage drop across a resistor. So, when the coil unplugged there's nothing pulling current and the voltage will go to 12v. And, probably when the dizzy is unplugged the module doesn't ground the coil so you also get 12v.

 

It should be plug and play if you use stock DS II parts.

 

This test shows up best if using a 12 volt test light , connected between coil neg and GRD. The test light should flash while cranking. The 12 volt pulse is to fast for many DVM.

 

That makes complete sense now Gary, I should have known that!

And Sean, reading up on the swap it seemed to be a simple plug & play job lol. I got a new module (with blue grommet) and distributor, both for an '80 or '81 I believe

 

I'd rep you if I could. You are right on.

 

Thanks, and BTW not only was your explanation of the "no current - no voltage drop" perfect ... it was done in under two lines.
I would have rambled on for two paragraphs

Jim

 

When I read "it was done in under two lines" I thought you were giving me a hard time - and rightly so. I even thought about including E=IR and explaining that when I goes to zero then E does as well. But, that means I'd have to explain that the E is actually the voltage drop, and ..... See!

 

Ok, my swap was plug and play (except for playing w/the carb settings and timing). You threw me off, when you said your using a 78' harness...I don't see how that's going to work without a lot of work.

 

It was a lot of work. I just had to dissect the '78 harness and track down my coil power wire to splice into the '78 harness and use my original water temp & oil pressure wires.

I did finally get it to fire! Had to play with timing & carb but it only hits off the starter and only when I hold it wide open throttle so back to some carb tuning now

 

If you mean it only hits while cranking then you may not have power to the DS module in Run.

 

Starting off w/the right harness is def. recommended. I'm not your guy on troubleshooting electrical issues...which is why I tracked down the right stock harness to use on my swap. Good Luck!

 

Giving you credit for the "rep", I got him, Gary.