Engine miss under load - ignition concerns

VTICH said

Wow, quick reply and thanks 67DART273.
It was your reply in a previous post the noted the voltage on the negative side should be down around 2V or so that lead me to try better grounding first.

I will not give up on the grounds just yet. I did not check the body ground. I do have a good ground from engine to frame. Continue the testing tomorrow I guess.

Thanks again for the body ground check idea, Paul.

Click to expand...

I may have lead you astray. Did you take the NEG coil reading running or with key on and engine stopped?

RUNNING would be higher, STOPPED should be very very low

Here's the thing about that coil NEG reading. The Mopar ECU takes the place of the old breaker points, switching the coil on / off by grounding the NEG coil terminal. Points have "a little" resistance, and worn / bad points have "more" resistance

An ECU has the same equivalent resistance......it's going through a big switching transistor (the one you see on the case) and you are dealing with the "resistance" of that device plus possibly other components.

So ANY resistance between the ECU case and the battery NEG terminal is going to reduce the current through the coil