I believe the industry standard for ohm resistance is 15,000 ohms per foot. Thus, two feet of ignition wire would be 30,000 ohms, three feet would be 45,000 ohms and so forth. Disconnect the wires from both ends before measuring. Doesn't matter which ends you use positive or negative leads on, just measure how long the wire is (in inches, convert to feet) then use the standard 15,000 ohms per foot, touching the positive and negative leads on either end of the wire. Move the wire around while taking your ohm reading, or use the conuity (sp?) setting on your voltmeter...this test will tell you whether or not you have a break in the wire. If the needle fluctuates while doing this test, your wire is bad. (a break in it) Very high ohm readings means bad wire, i.e. high resistance. I have used the MSD 8.5mm wires for years, about 30-50 ohms per foot. The lower the resistance in your wire, the better the electricity flows, the happier your GN will be. I've seen that 8 and 10 are not different in ohms readings at all, just the 8mm is total wire thickness (insulation, etc.) So, an 8mm is about 5/16 inch in diameter, the 10mm is 25/64 inch in diameter, approx. It's all about the resistance in the inner core of the wire that you need, not total wire thickness. Get the least resistance you can for your wires. Use the high ohm setting on your voltmeter. But, anyone here reading this, please correct me if I'm correct.:tongue:
Using a dc ohmeter to measure spark plug wires is not a fair test. The wires are subject to high voltage and high frequency. The impedance changes with frequency so what you measure with your dvm means nothing.
If you have old wire and want to test to see if it's 'ok' then just replace them all. If you have new wire and you believe that there's an open somewhere then you can use the ohmeter as a relative measurement. Just because 1 wire measure 10kohm-foot and another one measure 250ohms-foot does not necessarily mean that the lower one is better. It's an art to design high frequency conductors.
xrunner123 is absolutely correct. About the only thing you can use a ohm meter for is to check for breaks and comparitive trouble shooting (and that's iffy). Other than that the resistance of wires is pure marketing.
How to check the plug wires is a good thing to know i suppose.
I use the Bosch plug wires from Autozone they have a lifetime warranty and only cost $30.00 when i bought them 4 years ago and i have used the warranty to replace them 4 times now, not that there was anything wrong with them i do it because i like having a fresh set of new plug wires on the car and to avoid having any problems from the underhood heat and the wires breaking down.
I think the price has gone up to $33.00 now for a set, they don't look to bad either with 8mm grey wire with black boots.
