Matt Lane

I am coming up on 38K miles, and and preparing for my second "30K mile" service. Did the first one when I bought the car at 16K miles. Car runs great, no cels, wondering if it makes sense to change the plug wires pre-emptively now. Or wait. Big $$...

Looking for your experiences:

1. At what mileage did you change your plug wires?

2. Were they causing problems, or was it preventative maintenance?

3. Did you notice a big difference? How did the old wires and connectors look?

Will be interesting to see the collective input!

Best,

Matt

Dwane

Save your money for the cup cars!

csertich

I just had my plug wires replaced at 47,000 miles. Got caught in a big rain and got a CEL. Turned out to be wires (figured this out from the cel codes). I got the old wires and connectors back and they were somewhat brittle and cracked. I don't notice any difference in driveability (other than no cel).

I think you can wait to replace them until you get a cel or other issues.

One item I would think about replacing is your distributor drive belt. It is also 16 years old and can cause more serious problems. And maybe your SAI check valve.

Just my thoughts....
chuck

Matt Lane

Thanks Chuck.

Dwane, that's not helping...

IXLR8

1995 C2 with ~70K kms...

1. Plug wires are still original, but they will be replaced this coming winter.

2. No issues with them, but they also do not see any rain. I'm replacing them because the outer rubber casing is cracked at the bends prior to the spark plug caps. Mind you, with stock valve covers, the ignition cables can't short to ground.

3. The connectors at the distributor caps and the spark plug caps look new.

I am making up my own set of wires this winter using Beru ignition cable and M3 terminals. I figure less than $80 for a set of 12 spark plug wires and 2 ignition coil wires.

KLSpeed27

I've got 87,000 miles on my origonal wire set with no issues, in fact I had to drive in the rain today (freak Texas weather).

Kika

I have 85K and on the original set of wires. I have been monitoring an occasional "P0300" Random misfire, which may be due to deteriorating wires, but I just passed smog 2 weeks ago, and have not had another CEL, so I am just keeping an eye on it at this point.
I did push all the connectors down on the distributor a few weeks ago, just in case there might by chance have been a loose conenction.

I think ultimately there is no "right" answer as to when wire need replacing, as all cars have expereinced different driving conditions and climates.

I beleive if your wires were in dire need of replaceing, you would start getting CELs, particularly the P0300, accompanied by the offending cylinder[s].

Akerlie

This is exactly how mine behaved, I think it is usually the lower wires for cyl 5 & 6 that go bad first (front right side).
Those where the only wires that didn't look like new on my car, could easily have just changed those two and eliminated the CEL.
Changed at 60K miles.

Mart993

Hi there,

My leads were 140k miles old and looked it! The previous owner said he had changed them lately, but I have my doubts! Checked a few with an ohm meter and the resistances were all over the shop!

Easier to change them as part of a service with a plug change. The results on my car were enormous.

It never had a missfire (apart from the start up surge which I have spoken about in a different post) but the engine is now smoother. Power seems about the same, but the car drives so much better! I wonder if one or two cylinders were only firing on one plug?

Mart

certz

I changed mine at 90K, along with a spark plug change, because the insulation on the lower wires, especially 5 & 6 as mentioned above, was cracking and deteriorating badly. That said, I never had a misfire or other plug/wire related issue, I did it as preventative maintenance.

targagr

I just ordered a set from Vertex.( Best price by the way and Sid is great to deal with and knows our cars)
I never had any issue exept for the car "bucking" a bit when i washed it.
My plugs look ok but i have 90k and i figure i should change them..

Stealth 993

I did mine @ my 90kmi service, it was a BIG waste of time & $$.

My thought is if you are not having arcing problems, or misfires, leave them alone.

993C4Smontreal

Nice Avatar Big N!

richardew

If mine have been replaced, I don't know about it. I've had it serviced regularly by Porsche and I don't think they do them automatically. Maybe they'll change them at the 300k service.

race911

130K on mine. (140K on the ones on the RSA.) And only problems when the car is wet after an engine bay washout. Funny when I let the car sit in my backyard over the winter, when the wheels were off for refinishing and the bumper getting painted, it sat uncovered one time during a HUGE rainstorm. Car would not start for 2-3 days until it dried out.