If they spec out to approx. 50 ohms/ft., Sound's like the way to go. I could't find a resistance spec for them. I have 4 yrs on my MSD Superconductors so far, which is a record for any wire I've used, but if you can get a wire that you can have replaced when they fall out of spec, eventually your gonna come out way ahead.

Keep in mind, by default, (resistance=heat) higher resistance wires will fail sooner, w/ all other variables being the same. Insulation quality is just as important, as it's effectivness (or lack of) will render the core structure irrelevant. High output coil's are a equal opportunity discharge proponant, preferring the path of least resistance. If that path is other than your spark plug, you lose!

 

The wires on my truck look and feel good and it does not seem to miss. The are the original motorcraft wires with only 48,000 miles on them but they are still 15 years old. Would it be a waste of money to replace the?

 

Check resistance of each wire, but sometimes just removal & reinstallation is enough to pooch the insulative sheath on older wires.

 

I did check the resistance on each wire. Most of them were in the 7500 ohms range. The number 7 wire was 10,500 ohms. Does this sound reasonable for these wires?

 

You got your money's worth out of those wires, replace them.

 

Is that to much resistance on the factory wires? What should the resistance be? I am still learning all about this stuff as this is the first older pickup I have owned.

 

The resistance is going to depend on what type of wires they are. Some use a built in resistance to suppress EMI, others use a wire wound around the center core for that purpose. Your issue is going to be high voltage leakage due to the insulator breaking down over time. A simple DC resistance check will never "measure" that value.

 

Good point. The insulation integrity is probably even more important, as the the resistance required to initiate spark across the plug electrodes is many times more than what is overcome through the wires. The spark pulse will however seek the path of least resistance, & leakage is the worst enemy.

Misting water on & around the plug wires with the engine running in the dark will give visual reference to leakage. Both at idle, & w/ rpm varied will show a good indication of what's really going on.

The less path resistance, the more likely is will stray from it's insulative confines. The better the insulative confines, the more resistance will have to be overcome to stray.

 

I will try misting them with water when it gets dark and see what happens. You guys brought up some great points. I am learning so much here following these forums. It will be interesting to see if these plug wires that are 15 years old and 48,000 miles pass this test!

 

On my 95 4.9 the original wires are functioning but the boots and terminals are becoming worn and I plan to replace them later this month with a set of "name brand" spiral core wires. It did pass the mist test and some nasty rain from "EARL" but in this case change is good. The cap, rotor, and maybe the coil will also be replaced at the same time.

regards
rikard

 

Rik I'm a firm believer in the old addage *if it aint broke don't fix it*. BUT you sound like your going to be doing the same thing I'm doing with my 1990 4.9L and in this case I'm going to the Accel high voltage electronic super coil and I am going to replace: Cap/Rotor/Plugs/Wires and take the added measure of also replacing the ignition module too, so that the ignition system will be comprised of all new components Except for the distributor assuming it's still good, if it's bad it'll get replaced aswell

 

Then a little gap stretch & timing bump, you'll think your driving a different truck!
FullSizeBronco.com - 78 - 96 Ford Bronco offroad club, forums, tech, installs

 

Are we forgetting the PIP senor (Stator) within the distributor?

The TFI (ICM) & PIP are definitely if it ain't broke items, but the other items will degenerate at a much faster rate. Coils weaken w/ age/use. One reason plug gaps are ranged rather than one single measure (.042-.046/ .044 being the average) This is the reason you can increase your gap by 25% after the ignition system upgrade.

 

nope didn't forget just figured that the ignition modules cheap enough that if I'm doing all that it'd be agood idea to also replace the ignition module for good measure you know???

 

on that note whats the most plug gap you'd allow given the voltage increase to the plugs I was thinking .055-.060 is that doable or would that be too excessive????