1965 gmc 305v6 ignition problems.
 

Hey guys looking for some insight on a problem I'm having. I've pulled a 65 gmc 2500 series out of the weeds, with a 305. I was hoping to get it running, to make my restoration and ls swap easier as I will need to move it around due to limited work space.
So steps I've taken are to run a compression test, which was good. Then it was time to get the starter and alternator rebuilt, which is done. Now in the step of redoing the ignition system. This is where I'm having problems. New parts: all under hood wiring, battery, battery cables, points (set at .16), rotor, cap, condenser, plugs and wires, and coil.
The problem that I'm having is there is no spark coming from the coil, I have constant power to the + side of the coil from the ignition switch and starter. And I have an intermittent spark coming from the points and condenser, to the - side of the coil. But still no spark from the coil. I've gone through a few new coils. But still the problem exist.
I'm starting to scratch my head on this one it all seems to be in order. I've tried even switch the wires coming to the coil still no dice.

Thanks for listening,





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Re: 1965 gmc 305v6 ignition problems.
 

BrettJ
Might be a bad ground. Check that the ground wire in the dist is still there or better yet remove it and clean it and the surface. Same goes for the new ground cable from the batt, clean the attach point on the motor.
Then careful check every component that you replaced to make sure it matches the original. (thats making a (BIG) assumption the the original was correct)

Did you rebuild the entire wiring harness from the firewall forward?
hh

Re: 1965 gmc 305v6 ignition problems.
 

Start at plugs and see what kind, strength, color or spark and work backwards. The grounding is very important as 319 says. ALL grounding!!! Batt to motor, motor to frame, etc. Double check the points gap. Be sure there is still 12V at coil when cranking. Also advise if you have modified any parts as said. Pertronics? hot coil? Wrong length plugs? What do you mean "no spark from coil" ? Exactly what kind of test did you run?

Re: 1965 gmc 305v6 ignition problems.
 

We have spark!!!! It was definitely the ground on the battery. I feel a little simple in the head. Hope to have running soon.


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Re: 1965 gmc 305v6 ignition problems.
 

Good info for trouble shooting for someone in the future. Hope ya get it running soon.

Re: 1965 gmc 305v6 ignition problems.
 

Well Brett was smarter than I was, he asked.. I and a friend spent two days troubleshooting the same problem and finally gave up. Figured it out about a year later.