Checking ignition coils: chasing a misfire.

[95scpa]

I don't know if this has been posted for the FWD 3800's.
I found a simple way to check the dual-output DIS coils, and it's worked every time for me.

Coil Check:
-Simply pull off one plug wire from the coil.
-Start the motor.
-If the coil sparks to the nearest mounting screw, it's good.
(You will be able to hear the arcing, it's not neccessary to see it. So you can check them by yourself.)
-If you don't hear any arcing, it's bad or the module is bad.
(Even if it passes a visual spark check @ .060" or 1/4"...)

To verify the module is OK:
-Switch the suspect coil with one of the others.
-If the miss or "no spark" condition follows the coil, it's the coil.
-If the doesn't follow the moved coil, it's the module.

*If the spark tests good at the coil-pack, suspect plugs or plug-wires.

Symptoms:
Miss under a Load, maybe worse in rain, runs decent if you accelerate slowly.

 

[95scpa]

I've also noticed the coil pack mounting bracket gets very hot, and heat kills modules.
White "Heat Sink Grease" should be checked and reapplied every year, between the module and the mounting bracket.
Removing the coils will allow the module to be lifted up to check.
Radio Shack carries it in tubes.
***Dielectric Grease is NOT good enough!**

To help with keeping the coil-pack cool, I made a heat shield like this:

I bought a piece of aluminum step flashing from the lumber store(Lowes).
I removed the 3 coil-pack mounting nuts under the bracket.
Lift the coil-pack assembly out of the way.
The flashing is pre-bent, so I just held it up to the bottom of the coil-pack where I wanted it and pressed it against 2 of the mounting studs.
The dents made by the studs shows where to drill.
Simply drill out the 2 holes.
Add 2 or 3 washers between the aluminum flashing and the coil-pack for some air space to aid cooling.
Slide the coil-pack studs back into place with the shield sandwiched in between.
Tighten the nuts and that's all....
Now I'm able to touch the coil-pack w/o getting a 3rd degree burn.:smile: