LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

arcing at plug

Old Aug 11, 2004 | 12:06 AM
  #1  
1982z28with18s's Avatar
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arcing at plug

#3 and #7 I can see arcing at the plug. It appears to be coming from the wire to the head(blue light). I've replaced the wires, and swapped #1 and #3 plugs but it still did it on #3 and #7.(plugs looked good and were gapped fine) I replaced the coil since I could finally see it arcing at the coil but I still got it arcing on these two plugs. I believe this is what is causing my slight stumble I am having when at part throttle. I don't think its arcing on the coil anymore(at least I can't see it) but it still arcs on the two plugs. I have ngk plugs and taylor wires. The wires aren't touching anything or burned at all. Any ideas?

Last edited by 1982z28with18s; Aug 11, 2004 at 12:43 AM.
Old Aug 11, 2004 | 01:49 AM
  #2  
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Re: arcing at plug

Narrow up your plug gap to .035.High resistance will cause it to arc and a wide plug gap IS high resistance.Wide gap smoothes up the idle and that's about all,except sell tune up's.
Old Aug 11, 2004 | 09:47 AM
  #3  
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Re: arcing at plug

Pick-up some dielectric grease from your local parts store. Smear a light coating inside the spark plug boots. Make sure that your boots are also fully seated; you should hear a click/snap.
Old Aug 11, 2004 | 09:49 AM
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Re: arcing at plug

You could also have a slight crack in the ceramic of the plug, I would lower the gap first as 1racerdude suggests then if it doesnt work try a different plug.
Old Aug 11, 2004 | 09:59 AM
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Re: arcing at plug

I think changing the gap is nothing more than a band aid. The wires should not arc and if they are there is a reason for it. I personally would try the dielectric grease idea and if that didn't work I would replace the wires (the two that are arcing) even if they were fairly new. Changing plug gap to compensate for a arcing ignition system is not fixing the problem.
Old Aug 11, 2004 | 11:39 AM
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Re: arcing at plug

Originally Posted by 1stz28
I think changing the gap is nothing more than a band aid. The wires should not arc and if they are there is a reason for it. I personally would try the dielectric grease idea and if that didn't work I would replace the wires (the two that are arcing) even if they were fairly new. Changing plug gap to compensate for a arcing ignition system is not fixing the problem.
Bandaid or not it works.HuuuM, I wonder what happens to a lot of opti's every couple of thousand miles and they need replacing,I wonder why mine has 116,000 on it.I wonder why my NOS engines never miss at .015 plug gap.
Spark will follow the path of least resistance and if it can't jump at the plug it will jump upstream,it WILL go somewhere. You don't just throw a 60-70 dollar set of wires away just to say you did,you try to fix the problem.To many people throw parts at a problem and not fix it and that cost a lot of money which you seem to have plenty of.
Old Aug 11, 2004 | 12:15 PM
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Re: arcing at plug

Another point is that proper wires connected correctly and plugs gapped to factory spec should not be causing arcing issues.
Old Aug 11, 2004 | 12:30 PM
  #8  
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Re: arcing at plug

Originally Posted by shoebox
Another point is that proper wires connected correctly and plugs gapped to factory spec should not be causing arcing issues.
I will agree 100%, if his engine is "stock".
Old Aug 11, 2004 | 11:53 PM
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1982z28with18s's Avatar
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Re: arcing at plug

Originally Posted by WS Sick
You could also have a slight crack in the ceramic of the plug, I would lower the gap first as 1racerdude suggests then if it doesnt work try a different plug.
Shouldn't be the plug since I switched plugs and its still #3.

Originally Posted by OBE1 95Z28
Pick-up some dielectric grease from your local parts store. Smear a light coating inside the spark plug boots. Make sure that your boots are also fully seated; you should hear a click/snap.
It's already got dielectric grease on it.

I might have to try to regap the plugs to see if it helps.
Old Aug 12, 2004 | 01:24 AM
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Re: arcing at plug

As far as arcing goes, if its bad, something is wrong.

However, a while back someone said its not uncommon to see a blueish huge around the boot of the wire where it goes on the plug, VERY slight. My car does this, as well as my friends LT1 ... But its not really a noticable thing. Inless its pitch black, I mean like head under the hood, hood down some too to shade moonlight, and its still barely visable ... It DOESNT appear to cahnge with RPM's, and apparently is not hurting performacne.

He dynoed 268RWHP through an Auto with a Cat-back, and a K&N ( Not cold air just filter ) ( I spank him mercilessly , his is "pimp" though with mad chrome rims and a system )

If your car feels underpowered ... Possibly check the coil wire, and plug gap, otehr then that, I cant think of anything that owuld make it do that. Distributor WILL not. Coil could, the wires are new right ? Did it do it with the old ones ? If it was me though I wouldnt make the gap smaller if their gapped at what they should be ... .05 ? or maybe im way off but thats the # stuck in head rite now.
Old Aug 12, 2004 | 06:21 AM
  #11  
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Re: arcing at plug

Its definitely down on power, dyno showed it and track showed it also. I'm down roughly 20-25rwhp, and also its got a stumble at part throttle, that really shows up after the tc locks up. The dyno graph as smooth, not real waving though. Last night was good weather and the car was hooking good but I could only pull 12.0's at 113 with mid 1.6 60fts(which is normal for what I pull). This was in good weather, and in just ok weather the car used to go very consistent low 11.80's with worse 60fts.
Old Aug 12, 2004 | 10:09 AM
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Re: arcing at plug

Originally Posted by 1racerdude
Bandaid or not it works.HuuuM, I wonder what happens to a lot of opti's every couple of thousand miles and they need replacing,I wonder why mine has 116,000 on it.I wonder why my NOS engines never miss at .015 plug gap.
Spark will follow the path of least resistance and if it can't jump at the plug it will jump upstream,it WILL go somewhere. You don't just throw a 60-70 dollar set of wires away just to say you did,you try to fix the problem.To many people throw parts at a problem and not fix it and that cost a lot of money which you seem to have plenty of.
Didn't mean to offend anyone...I simply meant that if they are arcing then something must be wrong. I too do not like to just throw parts at a car to try to fix things which is why I suggested just trying just the two wires in question. Even fairly new wires can go bad...especially when subjected to extreme heat from headers or improper routing. I understand the concept of least resistance but a .050 gap with no insulation between it (plug gap) should still be easier to jump than a .035-.050 gap (plug wire to cylinder head or other grounded part) with insulation between it like the insulation on a plug wire...assuming the insulation is good.

Sorry if I offended anyone...maybe I should choose my words more carefully.
Old Aug 12, 2004 | 10:13 AM
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Re: arcing at plug

Originally Posted by 1stz28
Didn't mean to offend anyone...I simply meant that if they are arcing then something must be wrong. I too do not like to just throw parts at a car to try to fix things which is why I suggested just trying just the two wires in question. Even fairly new wires can go bad...especially when subjected to extreme heat from headers or improper routing. I understand the concept of least resistance but a .050 gap with no insulation between it (plug gap) should still be easier to jump than a .035-.050 gap (plug wire to cylinder head or other grounded part) with insulation between it like the insulation on a plug wire...assuming the insulation is good.

Sorry if I offended anyone...maybe I should choose my words more carefully.
No we need to settle this like men and thumb wrestle .

I know what youre saying, its jumping for a reason. But if the car is modded, or non-platinum plugs are being used the stock gap is now not really ideal.
Old Aug 12, 2004 | 10:47 AM
  #14  
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Re: arcing at plug

I can understand playing with plug gaps to maximize the performance of various engine modifications but I haven't ever heard of anyone doing it simply to fix a arcing problem. However, I read these message boards because I like to learn as much as possible about these cars and I try to be open minded so if that works for him then thats cool...I just learned something and I'm glad it worked.
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