Do plug wires need replacement?
 

This is related to an earlier post regarding a miss/hiccup/hesitation while pulling through higher RPM's under load. I'm leaving further injector or fuel issues (other then correct mixture, pressures, and new fuel filter) for later if ignition tweaks don't work.

The plugs (Bosch w5's) wires (Beru's I think) and cap have 9 years and 23 000 miles on them. The last 4 years and 13000 miles have been AX/DE and pleasure driving. The coil is 3 years old, and the rotor the same.

So I replaced the plugs with NGK BPR7es gapped at .31. Plug connectors and distributer connector rubber is still pliable, and the resistance from end to end of all the wires was between 3.8 and 4.1 KOhms. One or two connectors had what looked like some minor greenish stuff (some corrosion I assume) which I can probably scrape out gently. I haven't checked for a light show at night, engine running.

The removed plugs had some white-ish stuff on the electrodes. There was some minor carbon (black chalky stuff, very thin) on the base (bottom of last thread) of one or two plugs. Overall they didn't look to bad to my "just know enough to be dangerous with a socket wrench" eye.

Upon start up with new plugs, I instantly noticed it idled more smoothly. Couldn't take it out and run it up hard, as it was raining and not a good day for it.

So: Does one replace the wires "just because"? They look very good. I am planning on doing the cap at least, and probably the rotor, as the one that is in there is a rev limiting kind (probably not stock for an SC, I'm thinkin.)

A new set of end caps is almost as much as a new set of Magnacors or Clewitts. A new set of Beru's is $235 I think from our host.

Anybody got a resource for the blue Magnacors? Same size as stock. No drilling. Car is AX/DE/pleasure.

Thanks

I sent you a pm with the name of the place I got mine.
You could check at night for arcing - or inspect for cracked insulation when OFF using a lens.

Can't really argue with Keith.Max on this one.

But I don't think I'll click any the links in his sig either... although electronic cigarettes sound somehow not-too-seductively addictive.

Seeing a bunch of this kind of spamming lately. Please flag it when you see it, I do.

Dan

Your wires are probably OK. Symptoms of bad wires are a stumbling idle and rough running, especially after a car wash or driving in the rain, or on a damp day. After ten years though, you have gotten your money's worth.

I would replace the cap if you haven't. You should replace it with the plugs.

If your SC is a ROW car I think it uses the rev limiting rotor. If a US spec car there is a fuel cut off relay (located in the dash at the far left end)which is used to limit revs instead. Fuel is cut off to prevent damage to the catalytic convertor. I have seen a case where the US type cut relay caused " stumble/misfire" at lower revs than expected and was disconnected and a ROW rotor was used instead. If originally a ROW car you need to keep using a rev limiting rotor or perhaps a ROW engine has been installed which leaves you with both systems. Be careful if removing the rotor to confirm you still have rev limiting working.

On my 3.2, standard Porsche factory maintenance requires changing cap and rotor at 15,000 miles. If your car is the same, at 23,000, you are over 50% beyond that. I would start with cap and rotor and see from there. Cheers

I think you are referring to my post about hesitation and how I fixed it. Bottom line was that my Beru's were really bad - 33 Mohms on one of the wires!!!!! So, I replaced my Beru's with Beru's from our host for $179.00. The kit includes the coil wire. I went with Beru's because they fit perfectly and mine lasted 29 years and 122000 miles - so, that is a proven product as far as I am concerned. Yours are not far off the mark - my Bentley book says the wires should be close to 3 Kohms. Yours are pretty close....

As a side note, when I changed my wires, I discovered the previous owner had put in single electrode Bosch Platinum plugs - I replaced them with the Porsche recommended plug ($2.05 a piece - great deal) and the performance gain with the wire plug combo was unreal. My car is smooth and pulls a third stronger. Best $200 I ever spent.

Any info on performance of Magnecor vs. Beru?
I see original post had a comment about "No drilling req'd" with "Blue Magnecores". What is this about? Does something with Red Magnecore wires require modification, and if so - where/to what?


Thanks.

The Berus come with all of the clips and hardware for close to "plug and play" change out. The Magnecors require using your old Beru clips which need to be drilled out for use with the Magnecors. Cheers

Or, you can not worry about the clips and use some plug wire retainers from the auto parts store.

Thanks x2.

I went with a set of Clewitts from our host, a little more price friendly and have had no problems and a great fit, however you do have to drill out the plastic wire holders but its very simple.