Ive run into a problem while trying to get my 383 engine to start. I have had it started and running about 30 or so times since the build was completed. But now I have a very weak spark when I hook up a spare plug to the #1 lead and ground the plug. I have 12 volts at the ignition coil, I have replaced the ignition control module 3 times and the coil 3times to make sure that’s it’s not just something easy, the distributor is brand new with the build, the cap, rotor and wires are all brand new MSD, I have the battery connected to a charger while cranking, I have tried to just put a park plug on the coil wire and I get a speedy yellow spark instead of a hot blue or white spark. The plugs are gapped properly and are NGK plugs. I am showings no ALDL codes. I am running out of ideas. The engine is grounded to the unibody, I do have a high torque starter on the engine and I would question if it’s drawing a lot of power during cranking except that I have the battery plugged into a charger while cranking and the voltage drops to 10while cranking.

Ideas? I am using the Factory ground strap on the firewall, I’d think that was enough ground? I have aluminum AFR heads and my engine harness is Factory correct with no modifications.

 

What does the voltage at your distributor read while cranking?

 

You mean pink wire from the coil to the distributor?

 

 

OK, I think that would be considered normal.
If it is not inadequate grounds, then could it be the coil wire itself?
Assuming it is a separate external coil, is it grounded well?


Long shot but, are you using a ballast resistor, or is there resistance wire in the ignition circuit?

 

I removed the coil and bracket mount, cleaned the connectors and the mount, removed and cleaned the engine to battery ground and replaced the engine to chassis ground. I have a lot better spark now. It’s weird, nothing looked really dirty or corroded at all, I checked everything with a Fluke multimeter and I’m getting .03 ohms between all of the components (as good as I’m gonna get)