Engine has always run ruff..like a missfire. While checking for arching in the dark through my brand new plug wires after a tune-up, I noticed blue flashes down by the plugs. It seems that the spark is jumping from the boot across the insulator to the nut on the plug? I am using Autolite plugs 3924, MSD 6AL box, MSD HVC II coil, and moroso ultra 40 wires. Now I been reading up on this and it seems it could be two things. One is a corona effect and the other is flashover. I am not sure which is occuring.. It seems it is flashover due to the constant flashing like its jumping. As I understand it the corona effect is a constant glow. I am seeing a flash. However my whole ignition is brand new and there is no way I cracked 8 plugs while installing them. I also used dielectric grease on the boots.

 

I have no experience with dielectric grease, but could the grease be "coaxing" the juice away from the plug and plug wire? Electricity follows easiest path was my thought - and I'm assuming the dielectric grease is supposed to conduct - that's why it's used in the dizzy for the stock ignition module. I'm no expert, but I've never seen anyone put grease on the plug boots. Just a thought from a dummy

 

Well dielectric grease is meant to be used on the plugwire boots, to keep the plugwires from sticking on the plugs...meaning, less busted knuckles yanking em off....

I dont see why they would all be arcing, unless theyre like a complete mismatch between the plugs and wires but even then....just downright strange.

Im super familiar with 3924's thats what I run in my Edelbrock heads.....Is there anything funny about the wires? Do they have a really shallow insulator over the plugs?

Oh and FYI Camaronewbie, the grease on the ICM, if you mean where it mounts, is actually used as a heat transferrant to keep the module cooler. If the module gets too hot it will shut down and the car will lose spark completely til it cools.

 

Cool - now I'm a little less of a dummy. LOL

 

im a Newbie also, but i just had problems with my tuneup, did u make sure that the metal piece in the Boot Snaped on hard to the spark plug, might be jumping outa boot somhow...

 

Check the ground strap on the back of the engine - to firewall. Take it off and clean up the contacts, and make sure to get it tight again. Read ULTIM8Z's post in the DIY PROM board about how he had only a ground strap on the front to an accessory bracket, and some of his plugs were arcing and causing a bad idle. Cost him 4 years of trouble.

Also, did you use any silly thread sealant on the spark plug threads? A drop of oil is good enough in iron heads. If the resistance between the threads and the heads is too high, it makes the spark want to go elsewhere.

Cracked plugs will do the same, but as you said - it's hard to crack 8, unless you wrenched on them with a normal socket, or just plain had a bad bunch to start with.

 

I'm having this same problem.. have you found the solution?

 

I hate to bring up an old thread but, I have a low mileage trans am and it is doing the same thing. Rough idle and in the dark I can see all the plugs arcing, also arcing around the cap.. it has new plugs wires cap and rotor????

 

Just throwing this up into the air...

What are you guys gapping your plugs at?

spark will take the path of least resistance, i guess if they were gapped huge it could cause excessive arcing... maybe not...

 

Word to the wise in any aspect of electronics and cars.

More grounds are always better than fewer grounds.

Period.

When in doubt ground it out :-)

This is from a former dealer tech, diehard car junkie and self taught tuner and some stereo experience as well

later
Jeremy

 

Bad or lack of grounds can cause some very weird issues!

 

the new spark plugs wires could be bad??

 

i can't even guess how many plug wires i have put on in my life, but something i learned about using dielectric grease on the plug wires is, don't do it.
sure it makes the wires much easier to remove when you do the next tuneup, but it also can cause problems.
anytime im working on a driveablity problem & i find that grease in the wires, i clean it out of the wires, off the plugs & cap or coils first thing & recheck for problems, its been the source of a run problem too many times for me to ever think about using it.

i see more problems with motorcraft & autolite plugs firing down the side of the plug than all the other brands of plugs all together. i have seen more motorcraft & autolite plugs burned out internally than all other brands put together.

very closely check inside of each wire boot for carbon tracking, if there is any sign of it that wire is junk as is the plug it was on.