FireRescue

The car a 92 corvette continues to miss after modifications. Car continues have arcing in the area of coil and plug wires both sides. I have changed three sets of plugs and wires, two coils, have new opti and have tried two computers. After the last arcing, I replaced the plugs and wires. The car continued to miss-- at idle and under load constant speed. The car shutters and jerks and sounds as if incomplete combustion is occurring. So, I drove the car last night still have the miss. Parked in the garage and looked under the hood in the dark--arcing has returned on the new wires and around the coil area. The coil is a constant glow, not the entire coil just a line. What could cause so many wires to short out? Find this out and I might be able to fix the miss.

Thanks Brian

TRACKMAN2

had a lot of problems with plug wires my self i got a set of the (cut ur own) wires and got some good heat insulator tube and put it on the wires before i put the ends on. (most custom fit wires for lt1s dont fit anyway) no more arching..... but what do you mean by "just the line"

1963SS

I've hd no arcing problems so I'm not sure what can be causing yours. Once the coil arcs it's likely that it has "carbon tracked" and that will make a convenient path for future arcing. Try scrubbing the coil area where the arc is with some WD40 and a Scotchbrite pad. That should get it back to virgin material.

As far as the wires....what wires are you using? I've never seen arcing with Taylor Spiro-pros or OEM wires. They're all I've used. Part of the "if it ain't broke, don't fix it" concept. If your NEW wires are arcing out to each other or to ground then I'd be tempted to say that they are an inferior quality. There just ain't no other option unless you have way too much spark and I don't see that happening.

FireRescue

Does anyone have any idea why I continue to arcing in the plug wires? 3 sets in less than 800 miles. The coil area arc appears to be just a glow--steady in a straight line. Three different manufautures of wies al the same result. In addition each time I change them it never fixed the miss.

TRACKMAN2

what do u mean straight line from where to where from the coil to the head or from a wire to the head,block or header?

FireRescue

Not sure looks like it could be a wire, does not appear it is the ground. Almost looks like it is on the right side of coil if looking from from to back. The plug wires arc as all plug wire do, random flases in different location on different wires.

TRACKMAN2

try the wraped plug wires first http://www.designengineering.com/cat...n/protect-wirethen try to put some insulation around the wire from the coil question then if that stops the arc let us know seems weard though. never had wires to coil arc they are low voltage.

c92vette

I'm a bit confused but will try to help. You say "Car continues have arcing in the area of coil and plug wires both sides." which bothers me. There is only 1 coil on the OEM LT1 on the right front of the block. There is only 1 wire that would have enough power/voltage to arc there and it is the plug wire from the coil to the opti-spark distributor. If this is the wire arcing follow 1963SS's advice and scrub the coil real good. If the arcing is coming from the opti distributor follow the same advice that 1963SS gave you and scrub the distributor real good. Now then if this solves the problem it will be a temporary fix. You might as well replace either the coil or distributor, maybe both, as the arcing will eventually return in the not to distant future. Hope this helps. Good luck.

TRACKMAN2

wouldnt be the opti......

3D87C4

Ah...something this noob is qualified to respond to. I design high voltage transistors for a living (so know a bit about spark discharges & related phenomena) & recently noticed this paragraph in my '87 FSM (page 6D4-2 Ignition System):

What you describe---"The coil is a constant glow, not the entire coil just a line"---may be corona discharge. When there is a high enough electric field there can be a discharge in the air itself---no electrodes needed---that can be seen and heard. This is the crackling sound you will hear near high voltage power lines, for example. A steady glow as described above is ok---bright high energy sparks clearly associated with exposed electrodes or obviously cracked insulators aren't.

Since you have replaced the wires 3 times, & the problem remains I think you can safely assume the problem lies elsewhere. I'm sorry I can't help you with that, but knowing what isn't a problem can be helpful sometimes too.

Good luck,

Wayne

TRACKMAN2

arora borialis under the hood interesting.

1963SS

I've just retired from a highly successful career as an Electrical/Electronics engineer. I've dealt with a max of 34,500 volts and am very comfortable with it. We had transformers that took this voltage and stepped it down to 315-430 or so using wye and delta taps. Our little transformers probably weighed 65000 pounds of so with no oil in them. They ran a 70 ton electric arc furnace.

I've dealt with corona discharge but usually at much higher voltages. I would believe what you say except that I've never seen it in an automobile. He says the car is jerking and that's indicative of something arcing out or going to ground, not a corona effect. He says arcing is occurring between the wires.

I'd still like to know what brand of wires these are. I have seen new cheap wires not hold the voltage but I've never seen a quality wire display these characteristics. I'd have to bet that OEM or Taylor Spiro-Pro's would not do this. But that's just me.

87 vette 81 big girl

Not an Electrical Engineer like You Gunny or JFB from C4 also,
was a former electronics technician many moons ago.
But Corona electrical discharge does exist on any High KV spark ignited engine.
Most pronounced on high compression performance V8's with aftermarket capacitive discharge & True Magneto ignitions.
You can see the Corona discharge on a cool & low humidity fall night with the hood open on your hotrod or racecar in the dark & lights off.
Let your eyes adjust to the dark for 5 or 10 minutes.
On our C4's the underhood lights must be disconnected.
Looks like the 4 th of July fireworks going on in the dark.
Small Blue Corona electrical flashes all over the ignition wires.
Even the best $200 ignition aftermarket race wire sets will do this.
The very best I have found are MOROSO spiro pro wound wires or Talylor Pro Race wires.
Magnetos I use a special solid copper core ignition wire & High KV jacket not found on standard ignition wire sets available.
Least amount of Corona discharge taking place in the dark with the engine running.
Look around the spark plug porcelain insulators exposed not covered up by the spark plug wire rubber boots next to the hex steel spark plug shell in the dark.
You might not believe what you see.
From a 3 foot distance away in the dark staring at all 8 spark plugs & engine idling away,........
I can count them off in my head & aloud, 1-8-4-3-6-5-7-2 & over & over just by the bright blue corona discharges I see.
Pretty cool but then it points out the danger also of ignition inductive crossfire potential also.
Especially between cylinders #5 & #7. fire exact 90 degrees apart.

Brian R.

1963SS

Aw crap Brian, I was going to go to bed early tonight and now I'll be up waiting for it to get dark. I've checked my wires in the dark before but I wasn't specifically looking for corona discharge. If I'm all tired and crabby tomorrow it will be your fault. That discharge must be ionizing the air and ionized air will conduct electricity very well. Could that also account for his bucking and jerking and why isn't it more prevalent.

Did you just wake up this morning and say to yourself, "I'll find a way to keep Gunny up tonight?". I appreciate it.

87 vette 81 big girl

No,

I am just half insane like You are Gunny..........

Love Speed, Horsepower, Torque, Racing, Helping out others,
Kicking ********* asses in person, drinking with a Good buddie,
Listening to a good bedtime storie of how things used to be & old street racing action, ect............

I want god damn pics of Sammy's C4 dana 44.......
Give a crap less of fame on C4,
I just want to make sure its A- OK.
I gave it all my all for Sammy, that dana 44 is pure perfection built by my own 2 hands & brain.
He paid for it $$$, deserves to have it unmolested & exact as I shipped it to him.

Going for a ride in the 87 later when its dark vent off some steam.
Unplug the underhood lights on 1 of your hotrods Gunny, watch in the dark for 5 minutes.
You will see those blue corona discharge flashes also.
Important to keep #5 & #7 at least 1/2 inch apart entire length.
Know its a real pain in the *** on 2nd generation LT-1's.

Brian

3D87C4

The steady nature of the glow reported & replacing the wires 3 times with no change is what suggests corona rather than arcing, IMHO. Of course, if the wire sets all came from the same (cheap) manufacturor then a different (expensive) brand might be worth a try. Arcing/corona is sensitive to humidity, contaminants & dust so there is probably no harm in trying to resolve it by cleaning up, inspecting for good insulation on all the wires, & routing them properly. Otherwise, it may be time to step back & diagnose the problem based on the performance symptoms following the FSM and/or the collective wisdom here. That said, I yield to your experience Gunny & Brian.

Regards,

Wayne

P.S. did some googling on spark plug wire corona for grins. Didn't find much useful but here are two old Packard spark plug wire adds from Popular Science (1929) and Popular Mechanics (1937):

http://books.google.com/books?id=Wyg...epage&q&f=true

http://books.google.com/books?id=_to...0corona&f=true

I also found a forum discussion from 2002, but it didn't add anything new.

P.P.S. did a C4 forum search for corona. A lot of folks have turned out the lights & posted their observations. Post 13 in the thread below answers my post above (#10) nicely:

http://forums.corvetteforum.com/c4-g...k-tonight.html