Ignition.....
 

I’ve been having issues with my Chevelle lately as it won’t stay running at idle and spit/ sputters at higher rpm. I’ve changed everything in the ignition, it’s all new, distributor, coil, wires, plugs, etc... I’m currently running a Mallory Unilite mechanical distributor and coil, that’s it. Nothing fancy.

I noticed tonight that when I have the timing light on it, the light/strobe will stop flashing and then it will die shortly after that unless I rev it up to keep it running. If I keep the timing advance, a lot, it doesn’t seem to do it but as soon as I get it lower than 20* advance, it won’t stay idling.

It seems that when I rev the motor up, the timing retards for a second, then advances......?

There is a back story, one time when I was working on it, I started the car up and it ran fine but it started to smoke between the brake booster and the firewall. I accidentally forgot to hook up a ground wire to the ignition and a wire, not sure what it went to, got hot and was grounding out on the brake booster bracket. This always a couple years ago......I’m not sure if that has anything to do with the issue I’m having now or not.

Any thoughts on what might be the problem or how to diagnose it? I hate to keep buying parts if it’s not justified but I’m thinking of replacing the engine wire harness.......I’m not very good with electrical on a car but in so have a friend who is. I’m thinking we/he needs to check voltage on everything to see it there’s an issue.

Thanks in advance, Kurt

I had a friend who said to use a wire directly from the battery to the coil to bypass the harness and see if that works. I’m going to try that tonight.....if I get time.

Kurt

You could just measure coil voltage with it running. I have burned up a Mallory box putting full 12v to it. Your resistor wire could be giving you fits.

maybe try a stock factory distributor set up using stock wires, harness etc. and see if it starts, idles and runs. maybe process of elimination? Good luck KB.

If you are going to use a jumper wire for + then I would also use a jumper for -. You might use a Chrysler resistor with the + jumper to protect the ignition.

I literally just ran a wire directly to the coil, through the 1.6 ohm resistor, from the positive side of the battery and it fire right up with zero issues. The timing is set at 17* initial and 38* total....for now. Time to order a new engine wire harness!!!!

Thanks for all the replies, Kurt

Glad ya found it Kurt.

Good to hear. Good advice!!:3gears:

Isn’t the factory positive wire to the coil a resistor wire ? If so using a resistor would lower the voltage more ...

He bypassed the harness (with resistor wire) and ran a wire direct from battery and used a 1.6 ohm resistor. Basically simulating what the harness should do, and found the harness is at fault.