plug wire

[mluck]

how can you tell if a plug wire is bad

 

[fordconvert]

There are differnt kinds of bad. One way would be check it with an ohm meter. Other way is swap it out and see if your problem goes away. Mpst of the time if the spark is not going to the plug its going somewhere else.

 

[mysavioreigns]

If you just want to see if it is sparking:
Get a friend
Unhook the wire from the plug
Put a bolt in the end of the wire
Prop it up near something metal - not touching, but near.
You, or the friend, go and try to crank the engine. If you see a spark, then it is working.

Then, like fordconvert mentioned, you can test the resistance, voltage, all that stuff. Or, just get a new one.

 

[ludwig]

Get set of inexpensive new wires. They are only about 25 bucks. You can check them one at a time.

David (Falcon Performance Handbook) would suggest you check the sparking at night, when the spark is easier to see. Also, you can see any electrical leakage/arcing.

 

[The Plankster Prankster]

to just see if its sparking, you can also start the engine and then grab a plug wire, and you can feel a pulse as the power runs through the wire. but you might want to inspect the wires for physical damage to avoid getting knocked on your butt :roll:
the only failures i have seen of plug wires is their ends falling off/falling apart. one time i had a set of wires (with about 20k miles) and one cyl just wasnt firing right. pulled the wire off the dizzy and found teh wire's end in little pieces laying there on the cap, i was here at the farm, 25 miles from the nearest parts store, so i kinda threw it together just so and drove to town