Ignition control module (ICM)

[ZCurves]

Well, I will take any help that I can get! I am sure that whomever reads this in the future will be thankful.

Muchas Gracias!

[FastWoman]

De nada, mi amigo!

[z_ya]

3. Disconnect the wires from the (-) post of your ignition coil. Identify the wire that has conductivity with the #1 connector on to your ECU (beneath the driver's side kick panel), and reinstall it on the coil. Fold the remaining wire back on itself, and wrap it up in electrical tape. You may pull this wire back out later if you wish to revert to OEM.

OKay so do i take the #1 wire from the ecu and mount it to the negative on the coil?

[TomoHawk]

I was just wondering if anyone can tell us, what would or might happen if you only discconected the ignition box and didn't disconnect any of the wires from the ignition coil?

[Zed Head]

FastWoman wrote her instructions from memory, and might have added a wire. I think that there is only one wire connected to (-). The wire branches to other places like the tachometer and the ECU, it's not parallel.

The wring diagram shows only one for 76 and 78 (my car and hers).

The wire ends that are extra and that you need to worry about are the ones at the stock factory module location. One or more will have power when the key is on and one will still be connected to the (-) post of the coil (because of the branched circuit). Make sure that those are separated from each other and insulated from ground. 1978 is easy because it's a plug-style connection, 1977 and earlier use ring terminals and screws.

[TomoHawk]

On the 1978, the blue wire is for the tachometer and ECU stuff, and the black-white one is +12V

[Zed Head]

On the 1978, the blue wire is for the tachometer and ECU stuff,

...and the ignition module.

[z_ya]

My question still has not been answered.

[Zed Head]

I pulled it and tested it on the machine. The tester had failed it at low rpm but passed it at high rpm. ...

Is it normal for it to pass a high rpm an fail on low?

Assuming that "it" is just the ignition module. What machine/tester did you use to test it?

I've not heard of an ignition module testing machine. More info would be interesting, even if it doesn't help answer your question.

[z_ya]

Haha that was not the question. the question was do i take the #1 wire from the ecu and mount it to the negative on the coil?

[Zed Head]

Oops. The answer would be yes. But the blue wire from the negative on the coil already goes to Pin #1, and the tachometer and the original ignition module.

If you leave the blue wire on the coil negative in its original spot and just add a jumper wire from the coil negative to the C terminal on the HEI module, you will have things connected right. The jumper wire is a new branch to the new module, and the branch that connects to the old module isn't used anymore. You can run a jumper for the B terminal also from the positive post.

[z_ya]

I installed it and noticed a MAJOR increase in drive ability and its much smoother rpm drop when changing gears. I took the red and green and connected it to the module and for the coil I hooked it up off of what i call the "soapbar" ballast resistor. The only thing i noticed was that when I would rev it up the tach would jump around a lot but if i do it slowly it won't. Also after doing the swap it was a little difficult to start up (possibly be the ballast resister causing issues? Can i eliminate the resistor without any negative effects?) But other than that I am highly satisfied with this. Thanks for all the pictures and explanations I truly appreciate the help.