What would cause spark wires to arc? (besides bad wires)

bgilly · 03-27-2001, 12:33 AM

I hope you don't mind my cross-posting this to multiple forums, but I've got to get this figured out and I hoped some of you who don't visit other forums might have some input on my problem. Here's a copy of what I've posted...

I am on my 4th set of wires, and they ALL have arced wherever they can, whether it's wire to wire, or wire to a metal surface on the motor somewhere. I have changed plugs, cap, rotor, and cleaned the ground connection on the battery and where it goes to the timing cover. I have also tried disconnecting my MSD, and that didn't help. I started with Taylor 409's, then tried Pep Boy's cheapy wires, then Motorsport 9mm wires, then back to the Taylor's (of which 3 or 4 are burnt), and now I'm using Pep Boy's lifetime warranty wires that I picked up tonight. Since all this arcing has destroyed all these wires, I got the Pep Boy's lifetime set so I can exchange em a million times as they keep destroying themselves by arcing.
I started with Autolite plugs gapped at .045, then went to Motorcraft gapped at .052-.054, then regapped those to .035, which is where they're at now. Reducing the gap helped for about an hour, then it started missing again. The more I drive with these new Pep Boy's wires, the worse they're getting. They started barely arcing at all, if anything, and now they are arcing just as much as the others.
Please please please help me solve this, it's been 2 weeks since this has started, and its killing me and my love for my car.
Thanks a million for ANY input on this.

------------------
Ben Gillenwater
90 GT
------------------
10.5:1 28oz 347 ci
GT40 Irons
Cobra Intake
TFS Stage 1 Cam
3.55 Gears
And all the road-racing suspension goodies

84_GT350 · 03-27-2001, 03:50 AM

Well...assuming that nothing else has changed on the car, it either has to be a bad ground or some serious resistance in your ignition system somewhere. The reason wires will arc like that is because electricity always follows the path of least resistance. Usually that's to the plug but if for some reason the plug is bad or the ignition system is unstable then the electricity will find an easier path whether it be to another wire, a header, or the head. If it's doing it on ALL the wires, it's almost certainly a ground problem. If it were one or two wires I'd suggest you change plugs again. Double and triple check every ground in your ignition and electrical system (a pain, I know, but that's gotta be it). Check the MSD ground and the coil ground first. Good luck.

------------------
1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

03-27-2001, 09:31 AM

Do you have the MSD Blaster 3 coil with Power Tower? If so check the tall plastic piece for cracks (Power Tower). I had problems with my car running like crap and I saw the coil arcing against the shock tower, Power Tower was cracked.

Also do you put dielectric grease on the spark plugs and cap terminals? If not sometimes this can cause some arcing.

How about how the wires are routed. Make sure they are not hitting any metal. Make sure that the two cylinders that fire right together aren't touching, or you could end up buying a new pistons for those cylinders. I believe they are 6 and 5, I can't remember the firing order (13726548 I think). Anyway there are two cylinders that are next to each other that fire one after the other.

Do the wires get dirty when you put them on? I know they can get dirty, but if they get real dirty they will conduct electricity. Just wipe them off after installing them.

Last, make sure that you have good wires. I have the Ford 9mm wires and thought they were good at first, but now with MSD they arc all over. Buy a set of MSD wires after you have double checked everything.

Oh yeah, DOUBLE CHECK ALL OF THE GROUNDS. ALL IT TAKES IS ONE BAD GROUND TO MAKE COMPUTER CARS FREAK AND DO WIERD THINGS.

Hope this helps.

Jason

[This message has been edited by 88GT5.013.02 (edited 03-27-2001).]

LX XLR8R · 03-27-2001, 10:30 AM

def use dielectric grease but thats not ut problem..i would say get a 4GA wire and go from the frame to the head..i made sure my motor was grounded well..does it start ok? or is the starter slow?the only reason i ask is becasue if thats is screwy then you most definaitly have a bad main engine ground..o and use dieelctric grease not only on ur spark plus wires but on all ur electrical fittings(i.e. grounds and power leads to prevent corosion)

------------------
1987 black notch(ex 4 banger)
DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one..
AIM=onesillynotch

bgilly · 03-27-2001, 11:20 AM

84_GT350: Besides the ground to the timing cover from the battery, what other grounds on the motor can I check? That is, after I check the MSD and coil ground.
88GT5.013.02: No, I have a Crane PS92 coil. The next thing I'm gonna try is some dielectric grease. Somebody on the Corral had actually recommended that the other day, I just forgot to try it. I have routed the wires so that they are as far from anything as they can be, but that's hard to do in some spots. I'll have to check 5 & 6.
LX XL8R: I should really try that ground wire from the frame to the head. Just gotta find a good place to do it. The starter is better since I cleaned the timing cover and battery terminal. It was a little slow, but its getting better every day since I cleaned that stuff.
Thanks everybody, please keep it coming...

03-27-2001, 12:33 AM	#1
bgilly Registered Member Join Date: Feb 2000 Location: Los Angeles, CA Posts: 37	What would cause spark wires to arc? (besides bad wires) I hope you don't mind my cross-posting this to multiple forums, but I've got to get this figured out and I hoped some of you who don't visit other forums might have some input on my problem. Here's a copy of what I've posted... I am on my 4th set of wires, and they ALL have arced wherever they can, whether it's wire to wire, or wire to a metal surface on the motor somewhere. I have changed plugs, cap, rotor, and cleaned the ground connection on the battery and where it goes to the timing cover. I have also tried disconnecting my MSD, and that didn't help. I started with Taylor 409's, then tried Pep Boy's cheapy wires, then Motorsport 9mm wires, then back to the Taylor's (of which 3 or 4 are burnt), and now I'm using Pep Boy's lifetime warranty wires that I picked up tonight. Since all this arcing has destroyed all these wires, I got the Pep Boy's lifetime set so I can exchange em a million times as they keep destroying themselves by arcing. I started with Autolite plugs gapped at .045, then went to Motorcraft gapped at .052-.054, then regapped those to .035, which is where they're at now. Reducing the gap helped for about an hour, then it started missing again. The more I drive with these new Pep Boy's wires, the worse they're getting. They started barely arcing at all, if anything, and now they are arcing just as much as the others. Please please please help me solve this, it's been 2 weeks since this has started, and its killing me and my love for my car. Thanks a million for ANY input on this. ------------------ Ben Gillenwater 90 GT ------------------ 10.5:1 28oz 347 ci GT40 Irons Cobra Intake TFS Stage 1 Cam 3.55 Gears And all the road-racing suspension goodies

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03-27-2001, 03:50 AM	#2
84_GT350 Registered Member Join Date: Apr 1999 Location: Overland Park, KS, USA Posts: 1,631	Well...assuming that nothing else has changed on the car, it either has to be a bad ground or some serious resistance in your ignition system somewhere. The reason wires will arc like that is because electricity always follows the path of least resistance. Usually that's to the plug but if for some reason the plug is bad or the ignition system is unstable then the electricity will find an easier path whether it be to another wire, a header, or the head. If it's doing it on ALL the wires, it's almost certainly a ground problem. If it were one or two wires I'd suggest you change plugs again. Double and triple check every ground in your ignition and electrical system (a pain, I know, but that's gotta be it). Check the MSD ground and the coil ground first. Good luck. ------------------ 1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

03-27-2001, 09:31 AM	#3
88GT5.013.02 Guest Posts: n/a	Do you have the MSD Blaster 3 coil with Power Tower? If so check the tall plastic piece for cracks (Power Tower). I had problems with my car running like crap and I saw the coil arcing against the shock tower, Power Tower was cracked. Also do you put dielectric grease on the spark plugs and cap terminals? If not sometimes this can cause some arcing. How about how the wires are routed. Make sure they are not hitting any metal. Make sure that the two cylinders that fire right together aren't touching, or you could end up buying a new pistons for those cylinders. I believe they are 6 and 5, I can't remember the firing order (13726548 I think). Anyway there are two cylinders that are next to each other that fire one after the other. Do the wires get dirty when you put them on? I know they can get dirty, but if they get real dirty they will conduct electricity. Just wipe them off after installing them. Last, make sure that you have good wires. I have the Ford 9mm wires and thought they were good at first, but now with MSD they arc all over. Buy a set of MSD wires after you have double checked everything. Oh yeah, DOUBLE CHECK ALL OF THE GROUNDS. ALL IT TAKES IS ONE BAD GROUND TO MAKE COMPUTER CARS FREAK AND DO WIERD THINGS. Hope this helps. Jason [This message has been edited by 88GT5.013.02 (edited 03-27-2001).]

03-27-2001, 10:30 AM	#4
LX XLR8R Dirk Diggler Join Date: Feb 1999 Location: SLOATSBURG, NY Posts: 1,931	def use dielectric grease but thats not ut problem..i would say get a 4GA wire and go from the frame to the head..i made sure my motor was grounded well..does it start ok? or is the starter slow?the only reason i ask is becasue if thats is screwy then you most definaitly have a bad main engine ground..o and use dieelctric grease not only on ur spark plus wires but on all ur electrical fittings(i.e. grounds and power leads to prevent corosion) ------------------ 1987 black notch(ex 4 banger) DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one.. AIM=onesillynotch

03-27-2001, 11:20 AM	#5
bgilly Registered Member Join Date: Feb 2000 Location: Los Angeles, CA Posts: 37	84_GT350: Besides the ground to the timing cover from the battery, what other grounds on the motor can I check? That is, after I check the MSD and coil ground. 88GT5.013.02: No, I have a Crane PS92 coil. The next thing I'm gonna try is some dielectric grease. Somebody on the Corral had actually recommended that the other day, I just forgot to try it. I have routed the wires so that they are as far from anything as they can be, but that's hard to do in some spots. I'll have to check 5 & 6. LX XL8R: I should really try that ground wire from the frame to the head. Just gotta find a good place to do it. The starter is better since I cleaned the timing cover and battery terminal. It was a little slow, but its getting better every day since I cleaned that stuff. Thanks everybody, please keep it coming...