1. Inspect the routing of the wires. Improper routing can cause cross-firing.
2. Inspect each wire for any signs of cracks or splits in the wire.
3. Inspect each boot for the following conditions:

•

Tearing

•

Piercing

•	Arc through

•	Carbon Tracking

•	If the boot needs to be replaced, replace the complete spark plug wire.

Tools Required

J 39200 Digital Multimeter

1. Remove the spark plug wire to be tested. Ensure that the plug wire terminals are clean before proceeding.
2. Use the J 39200 on the ohmmeter setting.
3. Connect the test leads to each end of the spark plug wire being tested.
4. Gently twist the spark plug wire while watching the ohmmeter reading.
5. If the ohmmeter reads above 2,400 ohms, no matter how long the wire is, or fluctuates from infinity to any value, replace the spark plug wire.
6. If the resistance of any spark plug wire exceeds following ranges, replace the spark plug wire being tested:

•	0-380 mm (0 to 15 in) long wire = 0 - 750 ohms.

•	380-635 mm (15 to 25 in) long wire = 0 - 1,250 ohms.

•	635-889  mm (25 to 35 in) long wire = 0 - 1,750 ohms.

•	Longer wire - the measured resistance should not exceed approximately 1,968 ohms per meter (600 ohms per foot).