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Spark Plug Wires

devil_tazdevil_taz Posts: 21
edited March 2014 in Honda
How long do they last? Does it depend on the make and model of the vehicle?
Is it necessary to change them for every tune-up?
My car needs a tune-up really soon (165 000km) and I was wondering if it's a good idea to change them.



  • adc100adc100 Posts: 1,521
    50K-75K miles. Except for AC-Delco which are good for 0-50K. I make it a practice to avoid them. They were no good in the 50's and 60's and are no good now (IMHO)
  • kinleykinley Posts: 854
    The engine was balking and running on less than 8 and being out of town, had them replaced in the big city for $325 total. Shop time = $76/hour and Sales Tax = 8.8% plus $9.50 charge to throw away the old wires. It's good to be back home again.
  • Do you despise thieves as much as I do? Given the opportunity, one must consider giving up a law practice, or medical practice in financial preference for a second career in professional automotive mechanics. >:o[
    adc100 is right on in his estimate for service life on plug wire harnesses, IMO.
  • I just replaced mine with Premium Bosh (copper wire) for 25.50. Changed them myself. Only a 4 banger though.
  • I don't ever remember replacing spark plug wires and I've driven several cars over 200K miles. I check them with an ohmmeter and if they are under 60K ohms I just put them in the dishwasher. None of my vehicles have ever had spark plug wells. If they did, I probably would replace them now and then. If you get the dirt and salt off they will last longer than the car.
  • brorjacebrorjace Posts: 588
    I let the stock wires go in my Honda Civic for 70,000 miles and when I replaced them using Accel ThunderSports, I got 2 additional mpg. >:^)

    --- Bror Jace
  • q45manq45man Posts: 416
    My 90 Q45 has 8 coils, one mounted on each plug.
    This topic will self extinguish as fewer and few cars are made with plug wires due to emission requirements.
  • I change my wires every time I change my plugs regardless of the condition. Every 50,000 miles I will do the spark plugs, wires, distributor cap and rotor.

    I thought I could stretch the plug wires longer with the "lifetime warranty" wires but when I tried to remove them, 2 of the 6 wires pulled out of the boots. Now I just buy the standard grade replacement wires knowing that I will replace them in 3-4 years.
  • I feel for you, and like most people, I think that you were "overcharged", to say the least. However, it might not be quite as bad as it seems.
    I changed the wires on my 1996 Camaro this past winter. The wire set was $75 (Moroso Blue Max), and I, of course, did the labor. In order to access the wires, you have to drop the front end of the exhaust system, and the shop manual says to remove the power steering pump. I opted not to remove the pump, and all together the job took an agonizing 5 or 6 hours. Absolutely NOTHING is readily accessable on that car. Good thing I wasn't paying for the labor !!
  • cool thanks for the info guys.
    I took my dads '96 Lesabre in for a tune up, an oil change, changing of the spark plug wires and replacement of the pcv valve.
    The Total was around $400 cdn. SO DAMN $$$$. My friend told me that I got ripe off and it would be cheaper if I had gone to a independant shop (very hard to find a reliable one) But this is a one time thing since I don't need to replace them for another 150 000kms.
  • swschradswschrad Posts: 2,171
    I hope you enjoy those solid-gold wires, matching with the imported lead-crystal plugs.

    seriously, in US$, I would expect a dealership computer-assisted diagnosis and tune-up on a recent car to suck up

    $80-120 diagnostics
    $30-40 spark plugs
    $40-60 wires
    $5-14 PCV valve

    2 hours labor (call it $48/hour here)

    and you'd still get a little ripped off on the parts, but not seriously. if you snap open a cold one and diagnose the car yourself with the tested ShadeTree Evaluator (yep, there's an engine under the hood, har har), using factory parts would cost something like

    $10 spark plugs (from local chain parts house for the factory's own plugs)
    $20-50 factory fitted plug wires (depends on source)
    $4-7 factory PCV valve

    1 box bandages about $2.50
    1 tube Neosporin or similar antiseptic about $3.00

    1 police fine for the neighbor calling about the cussed-blue air $50

    and of course, if the ShadeTree Estimator didn't catch other parts and adjustments failed, extra costs at the dealer.

    why the difference? your dealer does not get parts from multiple sources, and the factory parts department sticks them for a number of service replacement parts. the dealer's parts man has his "adder" for parts department profit, and the service department charges a flat rate programmed into the computer that often provides an "adder" for profit there. they may or may not charge the Mitchell's number of hours, depending on how badly warranty reimbursement hacks them, but they will make up the difference somehow.

    the major cost difference is usually the computer diagnostic required for a successful tune-up nowadays. they might stick you double for the parts, depending on how evil the distribution chain is and whether that dealer wants after-sales service business, and the labor charges are usually required to be posted by regional laws.

    the rest might be real and "pretend" exchange differences between $CDN and $US, which out of $400CDN, I would expect to be in the $100 range.
  • acelinkacelink Posts: 106
    R7EQP NGK PLATINUM SPARK PLUG (LEADING) costs 10.50 apiece(?). Also, Ultra Cable (spark plug wire for 4 cyclinder) from Nagai Electronics Japan costs about $150 (heard about this brand?). Its manufacturer claim that it is 100% made of silicone or something. The vendor I talked to said, "just replacing the oem spark plug wire sets with this would net you some additional hps."

    Is he telling the truth? Are they worth upgrading given their exceptionally high asking price?
  • brucer2brucer2 Posts: 157
    Unless a wire goes bad (missfire) there is no need to change wires. You can get leakage if the wires are dirty (high voltage & a pulse - AC, skin effect). Once a year I take each plug wire off, spray it with silicone spray and wipe the grunge off (get inside the boots also). This keeps them clean and flexible. The ires will last many years like this. A dishwasher doesn't sound like a great idea to me.
    OEM wires are almost always good. NGK makes excellent replacements. Big buck, exotic wires are a waste of money with a stock engine.
  • A spark plug wire is just a conveyor of electricity. Almost all don't even have any wire in them. To reduce radio noise, they have been made resistive by making a bundle of carbon impregnated fibers or use of resistive plastic. The ones with wire in them have a thin wire wound on an insulating core core. They still radiate energy, but at a lower frequency that radios don't pick up. All you have to worry about is where the insulation touches other wires or the engine metal and the resistance, including the end connections. The dishwasher is a low stress method of cleaning the wires. Pulling on wires to clean them has the potential for more damage. I place the entire harness, including the distributor cap and spacers, in as a complete assembly. If you are including the distributor cap, do a second wash without soap to insure that no soap deposits are left on the surface. Pure deionized water is a extremely poor conductor of electricity. Water needs dirt and salts to conduct. WD-40 will clean but the surface will leave a coating to attract dirt. Then you are back to the original problem. Short periods of contact with water is not damaging.
  • wtdwtd Posts: 96
    Are plug wires supposed to arch when you touch them while the vehicle is running?

    I have been having problems on my 5.7L chevy truck engine. I replaced all my ignition components last fall because of low power and arching of wires and coil. All was fine untill recently. I checked the wires again and I had one that was arching which was replaced.

    I checked the wires again last night and although none were arching at idle, when you touched and moved the wires, they would arch. These wires only have 3,000 miles on them. Is this normal or are my wires shot?

  • alcanalcan Posts: 2,550
    No, they shouldn't. Are they GM or aftermarket wires? Any oily engine residue on them?
  • wtdwtd Posts: 96
    These are AC-Delco replacement plug wires. They do not have any oil on them. I wiped them clean a couple of days prior to checking them and they only had dust on them then. I don't know whats up with this ignition stuff. I replaced my plugs, wires, coil, cap & rotor with all new AC-Delco replacements and thought my problems would be over for awhile. I'm thinking of getting some Magnacor plug wires as these are supposed to be very good. Any thoughts on why these wires would be doing this so soon?

  • adc100adc100 Posts: 1,521
    I have had far to many failures with the AC Delco Wire Sets. I have had much more success with Autolites.
  • The insulation on plug wires is about three times thicker than what would be used at this voltage in other applications. It should be remembered that the spark plugs gap limits the maximum voltage. If you measure with a DVM, you will likely find that the resistance (>100K)is quite high on these wires. To experience your problem, the spark plug end connection would have to be very poor. These poor connections create an internal arcing condition in the wire. The arcing vaporizes the resistive components inside the insulation. This increases the gap at this bad connection. The voltage dramatically increases and takes any path it can. So it could very well be poor manufacturing.
  • I have a friend who works for NAPA. He swears by their top-of-the-line plug wire harnesses. You might get results with them. How sure are you that you have set your spark plug gaps correctly? Are you POSITIVE that your plugs are recommended for this application? Have you checked out your coil thoroughly?
  • wtdwtd Posts: 96
    The parts store where I bought the ignition components will warrenty everything. I'm going to get a Borg Warner cap, rotor, and coil. As for the wires and spark plugs, I'm not sure yet. They carry Omnispark plug wires which I have used in the past with good luck. I'm thinking maybe NKG plugs.

    I'm positive I have the correct plugs with the gap set to factory specs. The coil was new but that doesn't guareentee that its not bad.
  • If you have a digital multimeter, you might want to run some resistance tests.
    By the way, I used to sign on to Edmunds as wtd44. I noted along the way that you were a VERY close username, and to help keep ID's easy to ascertain, I switched to Fleetwoodsimca. My decision to do so was aided by a need to reformat my hard drive and reinstall my software! For good measure, I changed ISP's at the same time...
  • brorjacebrorjace Posts: 588
    Are NAPA ignition parts still being made by Accel? I heard this was true at one time ... but that was a long time ago.

    I really like my Accel Thundersport wires for imports. Mine were fairly cheap at around $40 for a Honda 4-cylinder, they look nice (3 colors to choose from) and have only 150ohms resistance (if my memory is functioning correctly this morning).

    I'll replace them again after 70,000 miles or so (maybe one more year). Still, they look brand new and it'll be hard to throw the 'old' ones away. <:^(

    --- <b>Bror Jace
  • These must be that spiral wound wire on a core. That price seems about right for this kind of wire.
  • brucer2brucer2 Posts: 157
    Low resistance wires and plugs shouldn't be used on modern electronic ignition systems. You wind up with lots of EMI that not only creats staic on the radio, but can create problems with the engine computer. Remember that the ignition is a pluse and is therefore AC, so don't worry about 15-30k ohm DC resistance weakening the spark.
    BTW, NGK also makes very good wire sets.
  • brorjacebrorjace Posts: 588
    I think those ARE spiral-wound wires ... but researched them and purchased them years ago now. I've forgotten and threw away the box.

    Brucer, most sets will say if they are for the street or not. Taylor sells sets of wires that should not be used on the street. I'm pretty sure wiring with a resistance of 150ohms per foot is street-legal. I've had no problems with radio interference in the years I've used my Accel Thundersports.

    Yes, you shouldn't use "race" wires on the street for the reasons you mentioned.

    --- Bror Jace
  • int250int250 Posts: 6
    referring to post #24 Echlin (NAPA) manufactures Accel products ! Both brands are very high quality !
  • int250int250 Posts: 6
    MSW wires are the spiral wound wires and Pep Boys carries them.. I have used then in modern cars with no problem !
  • brorjacebrorjace Posts: 588
    Um, on a related subject, how long do spark plugs last?

    My theory is that older engines, especially flathead engines like the ones made by Briggs & Stratton for lawn & garden equipment are spark-plug friendly. Even when these get fouled, a quick trip under a wire wheel and they are fine.

    Some engines, especially newer, hotter-running motors actually wear away the electrodes but if the electrodes aren't worn and using a piece of fine-grit sandpaper you can easily get the electrodes down to bare metal.

    Is that cleaned spark plug going to work as good as a brand new one? What else could be wrong with an old plug whose electrodes still look sharp necessitating its replacement?

    --- Bror Jace
  • zr2randozr2rando Posts: 391
    Just use a solvent and brush to get carbon and varnish off them. Main thing is the firing surfaces need to be flat and parallel,,,rounding off the corners is what kills them. Also check the insulator carefully for any cracks. If you are using inexpensive plugs it is usually cheap enough to replace them given all the effort it takes to get to them sometimes. Platinum usually does not wear enough to replace very often, usually just get carboned up and then you get some odd firing pattern if there is much gunk on them...if you have to adjust the gap be carefull, after all those heat cycles they may not want to move that one last time...years ago we used to clean them and file them repeatedly...lots of time, not much money, and pretty simple engines...
    Those were the dayyyys!
This discussion has been closed.