oil on upper end of spark plug threads near the ceramic part?

[look 171]

Finally had a chance to get in the Cayman. Found oil only on upper end of the plug thread. Where is it coming from? Valve cover gasket? The inside it bone dry and shiny, not a drop of oil in the spark plug hole. Maybe I can't see that well due to it being so tight in there? Plug looks OK?

I have a miss fire on No 6 cylinder so I swapped out the coil with another, go for a drive and see. Do you recommend I clear code before driving it? If code is cleared, how long does it take for code to appear again?

[Bob Kontak]

Yes, clear code. It will come back pronto if coil did not clear issue.

[look 171]

Thanks, Bob

[john70t]

Originally Posted by look 171

If code is cleared, how long does it take for code to appear again?

The code may come back, but it might not be smog-able until all drive cycles have been completed.
It's a little confusing and random but OBD2 wants to see the car burning clean when all possible scenarios have been driven.

(I'm a-ssuming the Cayman is similar to the 911)
https://forums.pelicanparts.com/porsche-964-993-technical-forum/382813-obdii-readiness-drive-cycle-procedures.html
https://www.smogtips.com/smog-question/2692/Porsche-911-Emission-Monitors-Not-Ready

[look 171]

Not for smog, but I am trying to fix a misfired code. I am thinking it has to be the coil, plug (more then llikely not), or the VVT valve.

[908/930]

Looking at that plug in the pic, threaded section looks really long. Possibly oil placed on threads prior to install. Have seen mention of conductivity problems with oil but I will still add oil or something, more worried about seizing. Good luck tracing your misfire.

[look 171]

I often use a little anti seizing compound on plug threads but read to never to use it on a Porsche. This is the fist time I am wrenching on this in a very long time. My mechanic died 6 months ago at 44, so now I must find someone else.

[908/930]

At age 44, yikes. I would also change the plug, just because. That looks like a plug they used for Mazda rx7 but 4 prong vs 3.

[john70t]

Originally Posted by look 171

I often use a little anti seizing compound on plug threads but read to never to use it on a Porsche.

Huh, I thought the copper anti-seize conducted electricity and was okay to use sparingly.
I was wrong.

https://ngksparkplugs.com/en/resources/5-things-you-should-know-about-spark-plugs
1. Anti-seize

NGK spark plugs feature trivalent plating. This silver or chrome-colored finish on the threads is designed to provide corrosion resistance against moisture and chemicals. The coating also acts as a release agent during spark plug removal. NGK spark plugs are installed at the factory dry, without lubrication or anti-seize.

Anti-seize can act as a lubricant, altering torque values up to 20 percent, increasing the risk of spark plug thread breakage and/or metal shell stretch. Thread breakage can sometimes involve removing the cylinder head for repair. Metal shell stretch changes the heat rating of the spark plug and can result in serious engine damage caused by pre-ignition. Do not use anti-seize or lubricant on NGK spark plugs. It is completely unnecessary and can be detrimental.

[908/930]

Yes, I think about the problems caused by anti seize when I hear of threads getting pulled from aluminum heads from removing spark plugs after 60k or whatever the long interval is now. So far no problems with adding some lubricant. I never torque plugs.

[look 171]

Strange. Swapped cylinder 5's coil into the cylinder 6. Cleared code, drove it for 25-30 miles and no check engine light, no miss fire, nothing. I was really hoping to see cylinder 5's miss fire come up so I know its the coil.

[john70t]

Are those plugs factory-spec and blessed by the engineers?
(I was under the impression the 2/4 blade plugs were witch doctor quackery but IDK.)

Don't rule out fuel injectors, individual throttle plates if equipped, stuck/worn rings, other factors which would affect a single cylinder

[look 171]

Yes. factory plugs.

If stuck ring, there's no way for a code reader to tell but a miss fire on that cylinder bank? Fuel injectors would neither work of don't. If clogged, it will always run horribly. After my test drive, it drove well and smooth like it always did. Something if funny. I am going to throw new coils and spark plugs at it and clear code and just drive it. At the same time, change out cam and crank sensors too.Shooting in the dark here but those sensors will eventually go bad at some point.

[LWJ]

I have had coils with intermittent failure or progressive failure with heat. That could do something like what you say. Less likely is a bad connection with a coil. I don't believe that one.

Seems you have compression. And a weird electrical issue. You are doing exactly what I would do. there is a glitch in the circuit. Replace it. And drive it!

[Zeke]

If you use anti-seize just be sure the plug base is clean when it contacts the head. Keep the AS down in the threads. IDC what any factory says, stuck plugs is no joke. IDT it takes much. I can see as many different ways and quantities of AS being applied as there are fools applying it. People can screw up taking out the trash.

[Por_sha911]

Originally Posted by look 171

I am going to throw new coils and spark plugs at it and clear code and just drive it. At the same time, change out cam and crank sensors too.Shooting in the dark here but those sensors will eventually go bad at some point.

If everything is working fine, why throw parts at a properly running system unless it is time to put in new plugs? You may have had just a loose connector on the coil...

[Bob Kontak]

Originally Posted by look 171

Yes. factory plugs.

If stuck ring, there's no way for a code reader to tell but a miss fire on that cylinder bank? Fuel injectors would neither work of don't. If clogged, it will always run horribly. After my test drive, it drove well and smooth like it always did. Something if funny. I am going to throw new coils and spark plugs at it and clear code and just drive it. At the same time, change out cam and crank sensors too.Shooting in the dark here but those sensors will eventually go bad at some point.

What does "Something is funny" mean?

Clear the code and drive it now for a week before replacing a bunch of stuff.

If the code stays off, then replace everything for your comfort.

Isolate the problem first.

[Scott Douglas]

I'd just drive it until the code comes back or it starts missing again.

It could be that undoing/redoing the coil connector is all that was needed and everything is fine now.

[look 171]

Originally Posted by Bob Kontak

What does "Something is funny" mean?

Clear the code and drive it now for a week before replacing a bunch of stuff.

If the code stays off, then replace everything for your comfort.

Isolate the problem first.

I just don't have a good feeling about the electronic parts. From my experience, an electrical part neither works or it doesn't. I need to drive it more to see.

I do not work on that car much, it does have over 100,000 miles on it so the coils should be changed out? It difficult for me to accept the bad connection. Its tight in there and there seems to be no possible way for any of the connection to disconnect or fail? Those coil boots are on the plugs tight and screwed down.

[look 171]

Originally Posted by Scott Douglas

I'd just drive it until the code comes back or it starts missing again.

It could be that undoing/redoing the coil connector is all that was needed and everything is fine now.

Its electronic I am really hoping it isn't anything internal but that shouldn't be because its running fine now. Italian tune up, jsut to "blow it out" wouldn't work here sadly.