Is it necessary to replace spark plug wires at certain intervals?

[deskjockey]

Is it really necessary to replace the sparkplug wires every 60,000 miles? Can't you just check em' with an ohm meter and if it reads 0, they're still good? Do brand new plug wires read 0 ohms?

 

[rstarch345]

My Chiltons suggests 45-60000 miles. It's not necessarily the resistance that is the problem. You have to take in consideration the wire insulating jacket. Is it oil impregnated, cracked, dry, etc. Do you have any missing that could be related to wires. There is a lot of heat under the hood that can break down the insulating material. Even silicon jackets have their limits.In some respects, you can continue using them if you are not having problems. Me, I'm a fix it before I have a problem person. The factory does post replacing things before wearing out for good reasons other than the dealer making money.

It's your call. If you are running well, leave them. Otherwise, replace them.

 

[Dirt]

that's a service selling point. You don't have to change them until one starts arcing on the block (or somewhere else) or the connections get corroded. if thier corroded you can clean them. use common sense when checking under the hood if thier are hot spots on the wires or broken insulation. it's probably not a bad idea to change them but... plug wires are very resiliant and can take quite a bit of abuse. I think they actually have quite a bit of resistance though I dont think any plug wire will ever read 0 ohms. these guys will correct me if i'm wrong.

 

[RichP]

I do my plugs, cap, rotor and wires yearly, all dealer OEM. Cheap insurance.

 

[Spudboy]

:lecture:

Plug wires are designed to have a certain amount of resistance. The FSM or any service manual will tell you how much. IIRC, in the 10000-15000 ohms per foot range for OEM wires. Some performance wires may be different. If the wire reads zero ohms, there is something definitely wrong.

Once a year replacement might be excessive for most people but I would not go more than 3-4 years on a quality set which corresponds to the factory recommendation assuming 12000 - 15000 miles per year. Heat, oil, age, etc all conspire against rubber parts.

Spudboy

 

[Dirt]

i knew there was alot of resistance in them. can any one answer why?

 

[egon]

Dealer says every 30k, I use Accel wires, cap, and rotor and change them every 50k. My thinking is that the performance quality should last long in a DD.

--Matt

 

[RichP]

Bad plug wires will also contribute to coil failure, voltage gets reflected back into the coil, not common but does happen.....acts like a out of tune cb radio antenna.

 

[Spudboy]

i knew there was alot of resistance in them. can any one answer why?

Primarily to cut down on EMI in the radio, but can affect the computer as well. In the days of low quality radios, the wires had a copper or stainless steel wire core with essentially no resistance. In those cars, upgrading the radio to FM (gasp) required extra devices to get rid of the noise from the ignition. Lower resistance performance wires have extra shielding to take care of the EMI.

Spudboy

 

[Spudboy]

Re: Questions for RichP

Are you using the high-performance OEM wires or just the standard set? Also whats a ballpark figure for cost from the dealer. I have to get a set before my smog check and wondered how bad the damage is going to be.

thanks
Spudboy

 

[deskjockey]

I called the dealer yesterday $31.50 for the oem wire set, and they told me if I wanted the High Perf. set I'd be best off ordering from Mopar online. oem plugs are $2.75/ea. Total damage around $50.

 

[Spudboy]

Thanks. :wave:

 

[RichP]

I'd have to dig out the receipts because I have 3 jeeps and generally go and do a mass buy for all three, plugs, caps, rotors, wires. About $60 sounds right, the high performance wires are about $10 cheaper if memory serves. The last trip because the 2 TJ's were new to us included belts, idlers, tstats, rad caps and a few gallons of mopar coolant and two factory air filters. We spent the better part of a day doing them all.

 

[Spudboy]

Thank you as well.