1970 Pontiac GTO Sparkplug wires arc

MRGREENSBURG

MEMBER
1970 PONTIAC GTO
V8
2WD
MANUAL
54,990 MILES

I've had 3 sets of sparkplugs wires
on my car and still arc. Any ideas?
Thanks,
Greg

Sunday, March 15th, 2009 AT 7:58 PM

6 Replies

MMPRINCE4000

MECHANIC
8,548 POSTS

Do you have an aftermarket ign. System on car (MSD 6A or 6AL for example?).

Is arc at cap or wires? Are wires burnt?

Generally I would use a set of Taylor spiral core. You can buy a universal set and cut to length, use 8mm or larger. They also sell a heat boot that slides down universal set to protect the connection at the plug from heat.

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Monday, March 23rd, 2009 AT 6:59 AM

MRGREENSBURG

MEMBER
3 POSTS

I have stock ignition on this 1970 GTO
New ste of 7m ac delco wires. 2nd set.
They just arc everywhere at idle.
Do you think this problem is causing
my car to surge while driving?

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Monday, March 23rd, 2009 AT 4:42 PM

MMPRINCE4000

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Yes, it would cause surging. Either the wires are bad or the coil is putting out way too much voltage.

The new wires may have too much resistance in them, (newer wires do). I would try the Taylor Spiral core which have only 300 ohms per foot.

Also check ground to engine, make sure it is clean and tight.

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Tuesday, March 24th, 2009 AT 5:56 AM

MRGREENSBURG

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3 POSTS

Thanks so much for helping. I'll do what you
recomended. Greg

updated 3/27/09

I again want to thank you for your help. But no fix.
I got the wires you said to get and still arc. I guess i'll just keep trying.

Updated 4/20/08
Getting back to my arcing problem. Bad mistake. I put the wrong plugs in. But that just made the problem worse.
Put the right plugs in. Still has the hasitaton all the time. When cruising I get a miss like surge all the time. Even at just idling
down the street. Kinda jurks. Could it be the carb? Everthing else tune up wise has been replaced. Thanks for you help.

Greg

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Tuesday, March 24th, 2009 AT 6:03 PM

MMPRINCE4000

MECHANIC
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Check all grounds to block. Make sure the cap is not cracked, make sure the wires are not close to a heat source that could cause melting.

But I think that you have a bad ground to block.

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Friday, March 27th, 2009 AT 10:19 PM

MMPRINCE4000

MECHANIC
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Either the carb, or the timing.

Set engine to TDC #1, remove cap, rotor should be pointing directly at #1 cylinder, if not, remove and rotate so it does.

Start with 8 degrees BTDC with mechanical/vacuum advance off. No more than 36 degrees total advance.

As far as carb, take car to chassis dyno and have air/fuel ratio checked on dyno with wideband O2 sensor. Usual cost is under $100 for 2-3 runs.

If problem persists, check compression with mechanical gauge, look for low compression on one or more cylinders, indicating a bad valve, valve out of adjustment, too much pre-load, bad rocker, bent pushrod.

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Tuesday, April 21st, 2009 AT 6:01 AM