spark plug wire resistance?
Thread Starter
Acct suspended by request 12 Dec 2012
Joined: Sep 2007
Posts: 94
Likes: 1
From: Louisville KY
spark plug wire resistance?
Hello guys, still trying to track down a miss/stumble when hot on my 89. I have read that spark plug wires should be 5000 ohms per foot and also in other places that 500-600 ohms per foot is ok. Mine new Bosch is more in the 600 ohms per foot and all measure pretty consistant with this. Is this ok for the HEU system or am I supposed to be running high resistance wires in there. I threw my old wires away and didn't check what they were. Sorry no Helms here yet, but could someone verify what is correct here. Maybe I have bought too generic of a set
Thanks!
Gary / Louisville
Thanks!
Gary / Louisville
Melting Slicks
Joined: Jan 2008
Posts: 2,054
Likes: 120
From: AZ
You know you can edit a post, right?
I'll go measure a wire at relay the result (in an edit)
.
Added in an edit:
I measured #3 and got 8.2k. I seem to recall that the higher resistance wires should be used, definitely NOT the solid (like copper) wires. Besides, in our 'glass machines, the radio noise would be horrendous.
Like Rick says below, if you find one wire that is WAY higher, replace it, or as I have had success doing, reterminate it after cutting about an inch or so off the spark plug end. Non-solid wires can break; the conductive material, usually on the plug end, having been pulled on and internally pulled apart.
I'll go measure a wire at relay the result (in an edit)
.Added in an edit:
I measured #3 and got 8.2k. I seem to recall that the higher resistance wires should be used, definitely NOT the solid (like copper) wires. Besides, in our 'glass machines, the radio noise would be horrendous.
Like Rick says below, if you find one wire that is WAY higher, replace it, or as I have had success doing, reterminate it after cutting about an inch or so off the spark plug end. Non-solid wires can break; the conductive material, usually on the plug end, having been pulled on and internally pulled apart.
Last edited by whalepirot; Feb 16, 2008 at 02:11 PM.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Your new wires should have had the resistance value stated. That said, I've read both 5000 per foot, and I believe someone posted theirs said 800 per foot. Doesn't matter really, just read them. What you're looking for is an odd ball, and twisting them while checking them is part of the test...an important part.BTW, your vacumn reading sounded good to me. But given the nature of our beast (alot of plastic vac. lines) I'd still check them very closely.My NAPPA plug wires read 5000 per foot.
Burning Brakes
Joined: Jun 2005
Posts: 1,188
Likes: 13
From: Wallingford Vermont
I little history for ya....
I too was trying to track down a mysterious miss. I had some nice performance wires that I had installed the year previous. I pulled each wire and checked the resistance ('can't remember the specs; the FSM lists the ohms per ft). Each wire checked fine.
Alot more investigation takes place. Finally after being thoroughly stumped I started the engine. Dusk had begun to fall, and I then noticed the flicker of an ignition wire arcing against one of the air-injection tubes. WTF! I mutter to my self. The next moment I can only describe as "senior" and without contemplation the full ramifications of my actions. I grabbed said wire
and verified the condition of the HEI coil! ZAP, ouch "that was stupid" ZAP, ouch "geez, that hurts"ZAP ouch!
The amperage tightened my muscle to the proverbial monkey fist. Finally, I managed to withdraw arm from the engine compartment. After getting my fingers to function as a team again, I congratulated myself for finding the miss although my verification procedures needs work...
I too was trying to track down a mysterious miss. I had some nice performance wires that I had installed the year previous. I pulled each wire and checked the resistance ('can't remember the specs; the FSM lists the ohms per ft). Each wire checked fine.
Alot more investigation takes place. Finally after being thoroughly stumped I started the engine. Dusk had begun to fall, and I then noticed the flicker of an ignition wire arcing against one of the air-injection tubes. WTF! I mutter to my self. The next moment I can only describe as "senior" and without contemplation the full ramifications of my actions. I grabbed said wire
and verified the condition of the HEI coil! ZAP, ouch "that was stupid" ZAP, ouch "geez, that hurts"ZAP ouch! The amperage tightened my muscle to the proverbial monkey fist. Finally, I managed to withdraw arm from the engine compartment. After getting my fingers to function as a team again, I congratulated myself for finding the miss although my verification procedures needs work...
Thread Starter
Acct suspended by request 12 Dec 2012
Joined: Sep 2007
Posts: 94
Likes: 1
From: Louisville KY
My wires check much lower!
My wires average about 1500 ohms each with the short one being less somewhat less that that and the long ones getting up to around 2300 ohms.
So have I got the right wires?
So have I got the right wires?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
