MSD Ignition Coil Plug Wire Replacement

**FastLT1** · 12-09-2016, 07:14 PM

I bought a 1994 Z28 a few weeks ago that has just recently started losing power (doesn't spin tires anymore from a dig and sounds like it's hesitating in upper rpms). Well I came home the other night and got out while it was still idling and I heard a popping sound from under the hood so I popped it and found that the ignition coil wire is arcing where the boot touches the MSD coil.

I was told it's most likely the coil wire causing the problem and that I should replace that before trying to replace the MSD coil. Well I also have a 1996 Z28 with an OEM ignition coil and to trouble shoot, I wanted to just swap its coil wire to the '94, but apparently they're different and don't interchange? Is there a specific coil wire I need for the MSD or is the style just different because of the 1994 vs 1996 models?

Ive tried ordering just an ignition wire through the local Chevrolet dealer but they said they can only order whole plug wire sets. I guess ordering one wire just isn't possible in 2016? Lol any advice would be great

**SSlowBoat** · 12-09-2016, 07:21 PM

94 vs 96 have different coil wires. 94 has a normal style with a spark plug end and an opti end. 96 has two opti ends.

Tip to you, go to advance auto, buy the cheapest set, then you will have 9 of them

Sent from my SAMSUNG-SM-G935A using Tapatalk

**Spartan7** · 12-10-2016, 02:02 AM

If you call or email MSD and ask how to order a single wire, they'll sometimes just offer to send it to you for free. They've done that for me a couple times in the past.

**FastLT1** · 12-10-2016, 11:07 AM

Ahh okay I figured they would be different between year models. Thanks for the advice guys. But do you really think that just that one wire arcing would cause such a big loss of power all throughout the powerband?

**Injuneer** · 12-10-2016, 02:56 PM

If the coil wire is arcing, it's potentially causing all 8 cylinders to misfire. Not like a single plug wire that only affects one cylinder.

**Mrmaroon** · 12-12-2016, 03:59 AM

I may have an extra coil wire I can check tomorrow. Is your coil the 94 style? Can you steal the #1 or #2 plug wire off your other car and test it like that? (I don't know if that's a safe way tho.)

Sent from my iPhone using Tapatalk

**96z28SideSwype** · 12-12-2016, 04:58 PM

Pm me your info I can make up some wires. @FastLT1

**FastLT1** · 12-12-2016, 05:55 PM

Well a friend just picked me up a set of cheap plug wires from autozone and swapped the coil wire out. I let it idle for about 15 minutes and it did fine but when we drove it down the road to my grandpas and back, it started backfiring any time I gave it 1/4 throttle or more. Finally, it just died at an intersection and we had to push it into a church parking lot. Any time I cranked it, it would backfire through the intake and would just barely idle and as soon as I gave it gas, it would die.

So I had my grandpa come pick me up to take me home and I got the bad coil wire that's arcing and swapped it in the place of the new wire, and the car fired right up so we drove it home with no issues aside from the arcing of course.

One thing I noticed when using the new wire though, it kept wanting to slide back off the coil a half inch or so whenever I pressed it on but not to a point where it would disconnect or anything. I even had my friend push it tighter against the coil to see if that affected it trying to fire but it didn't. And the bad wire that arcs popped right on without backing off at all. So I'm wondering if that new one is even the right coil wire for the car in the first place. The part numbers are correct for it though

**FastLT1** · 12-19-2016, 06:55 PM

I just got home after being out of state since last week and 96z28SideSwype already had a box with TWO new coil wires waiting for me at home completely free of charge! To me, that speaks leaps and bounds of his character and MSD. Thanks again man!

**FastLT1** · 12-21-2016, 07:31 PM

So after putting the new MSD coil wire on, the engine still wouldn't fire up. I pulled the wire and grounded it to the strut tower and had my gf crank the engine so I could check for spark, and the coil wire was sparking just fine. So the MSD coil was getting spark through the wire. I did the same thing with the plug wire and spark plug to make sure the opti was getting spark through the plugs, and the plug was sparking just fine grounded against the strut tower. I also sprayed starter fluid in the throttle body to make sure it wasn't a fuel issue but it still wouldn't fire.

Well I ended up replacing the MSD ignition coil that was already on the car with a new AC Delco coil that I bought with those junk Autozone wires, and the engine fired right up with no problems. It runs good now and the new MSD coil wire doesn't arc, but in the complete darkness, I can see a very very faint blue glow coming from the new coil wire and the coil all around where it sits in its welded bracket. I can also see a slight blue glow where the coil wire is plugged into the Opti. And if I touch the coil wire with my finger, it looks like static electricity is coming out of my fingertip wherever I touch the wire.

Now I've read that this could just be something called Corona effect which isn't a big deal. But I'm not 100% sure that's what I'm experiencing. If I were to use dielectric grease inside the coil wire boots, would it help prevent this stuff? I'm not sure if it affects driving the car because I'm too scared to take it down the road for fear of it dying on me again. But I know with how it is now, it's idling and revving just fine