Ignition Wires

Gumart1 · February 20, 2006

It seems from my what others have said that Toyota Ignition Wires last a long, long time. My old '92LS had the original wires dated 1992 and when I tested them with my Ohmeter they all were within spec (less than 25 ohms resistance).

I am getting ready to change the plugs on my '91 and wondering if I should change the wires as well (approx. $110). My existing wires are dated 1998 and have probably 70,000 miles on them. I'm confident they will be within limits. The car is running smoothly.

Can wires be within spec and still have a negative effect on the performance? Can they damage other components before giving me symptoms that they are going bad? I suppose it may just be personal opinion, just as some people are changing their O2 sensors as maintenance while others will test them first.

Lexus says to change the plugs every 60k, but they do not specify an interval for changing the wires. If I end up changing the wires I will add the caps and rotors as well.

SKperformance · February 20, 2006

They can be within limits but be throw way off spec once under eletric load.

I would more worry when it reaches the 10 year mark if you have no blatent problems.

Threadcutter · February 20, 2006

It seems from my what others have said that Toyota Ignition Wires last a long, long time. My old '92LS had the original wires dated 1992 and when I tested them with my Ohmeter they all were within spec (less than 25 ohms resistance).

I am getting ready to change the plugs on my '91 and wondering if I should change the wires as well (approx. $110). My existing wires are dated 1998 and have probably 70,000 miles on them. I'm confident they will be within limits. The car is running smoothly.

Can wires be within spec and still have a negative effect on the performance? Can they damage other components before giving me symptoms that they are going bad? I suppose it may just be personal opinion, just as some people are changing their O2 sensors as maintenance while others will test them first.

Lexus says to change the plugs every 60k, but they do not specify an interval for changing the wires. If I end up changing the wires I will add the caps and rotors as well.

Gum:

The way I look at it is that my time is at a premium, so the extra cost of the plug wires is relatively small compared to the amount of/value of my time invested & possible benefits attained. Besides, if you put all that time into it & the car runs crappy (because you didn't change the plug wires), what have you gained?

If you change the caps & rotors, you will have to unplug all of the wires anyway. You'll get to "enjoy" the priveledge of "re-weaving" the new wires back into the brackets.

You'll get to "enjoy" the priveledge of "re-weaving" the new wires back into the brackets.

Oops, only true if you replace the wires........duh! :D

SRK · February 20, 2006

In the good old days tune-ups were accompanied with an oscilloscope check of the ignition system. If the trace showed good voltage and the coil output was fine, one left things like plug wires alone. Even the cap and rotor could be checked easily on the scope.

I find that far too many parts are replaced unnecessarily on these cars. If the dealers do it, owners complain, if owners do it, they insist it is required.

If your ohm check shows that the wires are within spec, then they are.

93ls400walt · February 26, 2006

factory wires are pre placed into their clips. Very easy. You may damage the " old " wires moveing them around during the plug change. Also the caps and rotors are only around $30.00. The caps have hard to get to bolts. But you will be very happy to have done the complete change.

jbarhorst2 · February 26, 2006

When I did my last tune up, my dealer said that they use this rule of thumb. On my SC300, the plugs are due every 60,000 miles and they change the wires every 120,000 miles. So, if you're wires were changed 70,000 miles ago and they still test good, then I would assume you are OK for another cycle barring anything odd happening.

Tom