KevinKernaghan Posted February 4, 2006 Share Posted February 4, 2006 Just curious, how do I know when spark plug wires have gone bad? What is the maximum resistance they should show on an ohmeter? If a replacement is required, how much will they be, will they be fit to OEM standards, and where's a good place to buy them online? my pathy is having some problems with misfiring and this seems like the next step before checking the entire O2 sensor circuit. Link to comment Share on other sites More sharing options...
88pathoffroad Posted February 4, 2006 Share Posted February 4, 2006 The O2 sensor will not cause misfiring. That's an ignition or fuel delivery problem. On plug wires, I generally just change 'em every 30-50K miles regardless, silicone and rubber breaks down under the heat and will eventually crack and arc out somewhere. The lower the resistance the better, AFAIK. Plug wire sets generally run from $35-55 for generic and more like $50-$75 for aftermarket. Link to comment Share on other sites More sharing options...
vengeful Posted February 4, 2006 Share Posted February 4, 2006 I change my plug wires, cap and rotor each time I change my spark plugs (40k intervals). I think I'm working on about 15k with the current set, and no problems thus far. I had original plug wires on my truck until 90k miles when I changed out the plugs, wires, cap and rotor, and did a major service on the truck. Took me 2 whole days, but it was worth it. I got 2-3mpg back and the truck seemed a lot more happy. Before doing the 90k, I was noticing an intermittent miss while decellerating. I also removed, cleaned and rebuilt the fuel injectors, replaced the fuel filter and ran a bottle of that fuel treatment stuff to clear out the fuel lines. Truck runs beautifully now...well, except for the squeal from my PS belt and my manifold tick. Argh. Link to comment Share on other sites More sharing options...
94extreme Posted February 4, 2006 Share Posted February 4, 2006 exterior of the wires being cracked or just looking old.. that's the only visual clue.. if you lift your hood at night sometime and see a rock'n roll show you better get some new wires fast on my first pathy, the original nissan plugs lasted about 90k miles.. this one one thing i completely spaced through the years.. there was hardly anything left of the plug (diode). :o the truck wouldn't start when it always did on the first click of the key. i normally check my plugs once in a while (maybe once a year) and when they are bad i do the tune up. from what i have noticed on all my different vehicles is that cap and rotor get used up the fastest.. wires seem to be the most long lasting - two sets of plugs easily. Link to comment Share on other sites More sharing options...
SC88Pathy Posted February 5, 2006 Share Posted February 5, 2006 exterior of the wires being cracked or just looking old.. that's the only visual clue.. if you lift your hood at night sometime and see a rock'n roll show you better get some new wires fast Hehe I was just about to suggest that. Either open up the hood with engine running at night or in a garage with all the lights off. If you see sparks time to replace the wires. Link to comment Share on other sites More sharing options...
89_trailboss Posted February 5, 2006 Share Posted February 5, 2006 keep an eye out for a set on ebay. i picked up some 8mm for 6.95! Link to comment Share on other sites More sharing options...
mws Posted February 5, 2006 Share Posted February 5, 2006 Different styles have wildly varying resistance values. BUT, all the wires in a set should have about the same resistance per inch. So measure the resistance and length of each wire. If one is wildly higher, it becomes suspect. Link to comment Share on other sites More sharing options...
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