One coilpack not getting spark but does have power at wire


New Member
Jan 29, 2020
Columbus ga
ok i just did a motor swap on my 2000 gt.everything works fine motor cranks right up but im not getting spark to the first coilpack on passenger side.changed multiple spark. But i am getting power to the wires just none out coilpack.any ideas why just one coilpack will not fire...but all other 7 do
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The first widely accepted Tranny
15 Year Member
Dec 24, 2003
30 Mins from a Ragged GT
Did you screw in the engine wire harness block at the firewall. I had this same issue with my plugs and wires. I was doing wire management and in the end I seated the block but never turned the wrench to actually tighten it down. Its worth a look

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Mar 21, 2019
Long Island
Here's the diagnostic list:

1. Check for 12V at the center pin of the harness plug.
2. Hook a current clamp to the control wires (requires an oscilloscope) and check for the current ramps (two ramps at idle and one while under load).
3. Check the spark output with an inductive probe (also requires scope). It should have between 5 and 10 KV.
4. Check for opens in the harness. Easiest thing is check resistance between the block at the firewall and at the coil pack.

I'm attaching traces for you to see what a functional coil will do.

The red trace is the coil current ramps at idle. The 14 Amps draw is maximum so it is not drawing that for any appreciable time. That's a good coil draw.
The spark output (blue trace) is low due to low compression in the engine.