I was replacing my opti the other day and I realized that theres only 2 wires in the plug going to the ignition coil. The white one and the black one. Theres a loose wire going from around that area to the ECM where you can see that someone clipped it off.
My question is, is that wire significant, what does it do, can it not being connected cause problems,and why would someone disconnect it.

 

What year is your LT1? There are two different coil harness connectors (single and double).

 

whats going on with your car? is not starting?

 

Its a 96 and theres three pronges on the connecter and the coil but only 2 wires. The engine runs fine for about 3 or 4 minutes then starts to stumble. If you turn the engine off and restart it its good for another 3 or 4 min. I figure its an open to closed loop computer issue. But Im trying to see if I can solve the problem myself cause it cost an arm and a leg to have these things tuned. The engine has cold air and headers if that helps.

 

According to the wiring diagram in my Chilton's, the 96-97 single-connector coil only has two wires going to it. A pink wire supplies 12V. Green wire goes to the ICModule.

The 93-95 dual-connector had 3 wires - pink 12V and an open space in the black connector; pink/black from coil to ICModule & white/black to IC Module in the gray connector.

 

I know the engine is a 96 . Its the green wire that is clipped. If theres no wire going to the ECM would that cause the problems Im having.

 

There is no wire that connects the ECM (PCM) directly to the coil. The PCM sends a signal to fire the coil to the IC Module, via the white wire on pin B5 of the PCM to pin "B" on the IC Module connector.

Are you sure you aren't confusing the coil harness connector with the ICM connector?

ICM has 12V pink wire to pin "A", black ground wire to pin "C", the white wire on pin "B", and the wire from the coil connector on pin "D".

 

http://shbox.com/1/1996_ec_03_ign_system.jpg

 

http://shbox.com/1/ICM_cooling.jpg
Im probably confused about the actual name of the part. Sorry Im new to working on LT1s or any electroniclly injected car for that mattrer.
Its the black part in the top of this picture that has no plug in it. Im not sure what year the one is in the pic. But mine has 3 pronges and only 2 wires white and black. The wire to the far right is the one thats missing. the wire thats running from there to the computer but is not connected on ethier end is Green. Im not sure if thats the original color or wire though. There is a green wire coming out of the computer thats capped off. Im not sure that this is were that wire belongs or were it goes. Thanks for the help so far.

 

The part on top of the bracket (no plug in Shoebox's photo of his 95 Z28) is the Ignition Control Module (ICM). That should have the wires I listed in my post above. The red part in the photo is the (aftermarket/MSD) ignition coil.

On the ICM, there is no green wire that runs to the PCM. The only wire to the PCM is the white wire from the PCM pin B5 to ICM pin "B" as I said in my earlier post. The green wire from the ICM connects to the coil, also as indicated in my earlier post (not mentioning the green color).