Testing Spark Plug Wires

[johnrix]

Can someone tell me what resistance reading I should expect when I test a spark plug wire?

[djmcmath]

Assuming you have stock wires in a car like mine ...

End to end resistance ought to be 3-5Kohms. The distributor end connector should be about 1K, and the plug end connector ought to be either 3 or 4K. Give or take. The wires should be clean, not cracked, no swelling. You can tell for sure if they're bad by running the car in the dark and peering into the engine bay. If you can see flashes of light, they're done for.

The connectors, btw, screw on both ends. This topic has been covered in some depth. I think this thread (Plugs and wires) was the most recent, though it draws heavily on data from this older thread (Ignition Wires). Does that help any?

(BTW -- it helps to know some background stuff -- what year, type of car, engine, etc.)

Dan

[rob'smobile]

so 900 ohm to 1000 ohm is good ?

[Bill Douglas]

It will be unlikely all of them are similarly bad, so test them and if you find one or two bad, reseat the connectors. This worked for me.

[fireant911]

I know that everyone's experiences are different but the wires I had previously on my car did some 'arcing and sparking' in the dark. This I thought was truly a sign of replacement was needed. I ordered new plug wires (OEM-stainless steel braided) from Pelican Parts and these too did similiar 'arcing and sparking' since new. The Bentley manual lists the resistance as "plug connector to distributor cap end........3kŮ" - this is addressing the 1978-1983 SC models.

[djmcmath]

Originally posted by rob'smobile
so 900 ohm to 1000 ohm is good ?

Well, that depends. Are you just testing the wire alone, or are you testing the end connectors as well? Do they all read about 900 to 1000 ohms? If all of your wires read about 1Kohm, that's probably ok. If one reads 1Kohm, and the others all read 0, you probably have a problem. If they have visible arcing in the dark, you should replace them. Seems like my wires all read just about 0ohm, and all of the resistance is in the end connectors.

Dan

[rob'smobile]

they all read between 900 and 1000 .Idid unscrew one and cut off an inch and it improve to about 500 , I was useing a fluke 23 series meter set on auto range

[djmcmath]

You cut the spark plug wire? Didn't it have a little crimped-on screw connector at the end? (concerned)

Dan

[rob'smobile]

the crimp connector is on the spark plug end I cut the screw end , also they are not the ones on the car they are some wirs i got as a freebeee