Spark Plug Wires

[joe_keefer]

hi guys,

what`s a good way to tell if your plug wires need to be replaced? they look great but i can just never tell.

thanks, joe

[Mike W.]

It's hard to really tell, but signs are hard to start in very wet weather and poor running at first when it's rainy. Obvious cracking, or even just really hard and stiff. BMW used a solid wire conductor with a resistor in the spark plug connector, unlike most domestic and Asian cars that used carbon impregnated fiberglass as a resistor and conductor, so they don't necessarly fail the same. Either can eventually break down so the insulation no longer is an insulator, and it makes itself known in the wet. Also the spark plug connectors can fail too, but they are replaceable individually.

I once had a Jeep pickup that was hard to start in the rain, finally one day it just flat wouldn't start at all. Even coasted down a hill and no go. Put new cables on it and bang, fired right up. They can get that bad.