stinkydog

Mine did the exact same thing after putting new coils in. (One of the old coils was definitely toast - the other was marginal). Personally, I think the new coils are putting out a much hotter pulse - which is therefore more inclined to arc somewhere and interfere with the entire ignition circuit, when one of them is disconnected.

Easy test to perform without running a disconnected coil: turn the car off, switch the coil leads to the opposite distributor (one lead is probably shorter than the other, so you might have to pull the blower tube to make room, etc.). Start engine again. There should be no difference.

greg1990964

Thanks for the suggestion. I tried that. I may have to just buy another set of coils and try that. They may of been a bad batch.

greg1990964

I broke down and just bought new coils, (again) and cap and rotors also again, since the electrode in the bosch cap came sliding out. I also bought new coil wires, and will do new wires when the motor is out this winter for a clutch.
Just throwing money in the wind...
I will post what happens, if anything.

Vandit

Old thread bump. Any update on this?

greg1990964

Yep. The car runs great, no issues since replacemnt coils and such. But I think in dropping my motor for a clutch job I may of found the real problem, and I think timing is what made me think it was the new ignition parts, and not that I also did motor mounts shortly therafter..I noticed when dropping my motor that the wiring harness that runs across motor that contains the wires for the two peg plugs on the rear fuse box also carries a positive battery cable. My cable is chaffed showing a inch or two of raw battery cable. I think before I did my motor mounts that were complety shot, the battery cable was bouncing around on engine tray adge and arcing off body etc. My guess is when I did motor mounts it snugged wire up against whatever it was rubbing on to make a solid connection. Just a guess. Or could of just been new plug wires. . I can't remeber if I tried the undoing a coil after I installed new wires. Oh wait, I think I did and would still die. It seemed to run perfect and I have a pretty good feel for when it is not at full power. Maybe it would die cause of the cable creating a short when unplugging a coil wire. Dist belt fine as i did a valve adjustmnet last night with motor out and saw rotor spin. Anyways, clutch arrives Wed, will have motor back in on Thursday. I will cheack again and get back to you. First time engine drop not that big of a deal.

Vandit

Sounds good. Lots and lots of work right there.

I just went through the car and replaced caps, rotors, and coils and was trying to test them the way you originally attempted and encountered similar results. So much so I thought 1 of my new coils was DOA (jury is still out based on what I'm reading in this thread).


Can someone confirm that disconnecting each ignition module is an effective way to isolate each coil?

Indycam

I can and will .

greg1990964

Glad to know I am the only one that experienced the car stall when disconnecting actual cool wire. It still ran when u disconnected the ignition module?

greg1990964

Meant to say NOT the only one experiencing the not running on one coil issue. Can't type well from phone.. I am at Big Apple circus with kiddo. Bored. Haha.

Vandit

Yea, it started up and idled fine w/ either ignition module disconnected.

greg1990964

Vandit, to be clear, it died when you pulled actual coil wire off either dist? I hope others try it and chime in. Oh wait, I should just try it on the other 964 in my garage. Duh. I think I may of months ago. I will do it again when i have time tomorrow.