CEL issues

[Frodo]

Have had a CEL (NON-flashing) on and off for awhile. 3000 miles ago (when the car had 48K miles), I took it in to a local Porsche place. The guy did diagnostics on it, which indicated "misfire, cylinder 1". He said it was very short-lived, could have been due to any number of innocuous reasons, and said I shouldn't worry. He reset the CEL and recommended "drive her hard" on the way home. I did, and everything's been fine since...until yesterday.

CEL returned, and I went back. Durametric readout again indicated "misfire, cylinder 1". The mechanic said it had occurred three times, all at very low RPMs (eg 700 RPM)---he seemed to think it occurred when I was cranking her, ie before the engine had really even started. He again seemed to think there was nothing to worry about, that I could probably go until the 60K maintenance to have it checked out, but also said I could pull the spark plug and take a look if I was curious. He reset the CEL and I went on my way. The 20-mile trip home was fine, no issues. However, I shut the car down at home, then went out like half an hour later and drove off. Got maybe 1/4 mile and she started missing noticeably, especially at low RPMs. I hobbled home and decided to pull the cylinder 1 spark plug.

Did so. As far as I can tell, the plug looks OK. I'm kind of a newbie when it comes to Boxster mechanics, so I'm really not sure. Anybody have any insight here?



Assuming the plug is OK, what would my next move be? If I take the coil pack and the spark plug in to a dealership, could they test the coil pack for me (as well as assessing the plug)? I haven't pulled the spark plug well (tube), but (inserting a clean finger in there) it seems to be clean and without any obvious issues.

What should I do next?

[extanker]

look at center of plug [white insulator] for cracks,carbon tracks. check outside shell for cracks,carbon tracks.look in coil boot for black line [carbon track] put in new plugs

[Frodo]

Thanks, I'll do that...soon as I find me readin' glasses!

[Steve Tinker]

You could also try putting the suspect plug into cylinder #2 and see if the problem moves with the plug. If the Durametric still shows a problem with #1 cylinder, then there's a good chance you have a faulty coil.

[Frodo]

Another insomniac, I see...

Yeah, I thought about that (switching plugs). Didn't really feel like taking another one out if there's any chance the coil pack/spark plug unit that I pulled could be tested independently (ie, without messing with any of the other "good" ones).

Does anyone know if that can be done?

[paulv]

Originally Posted by Frodo

Another insomniac, I see...

Yeah, I thought about that (switching plugs). Didn't really feel like taking another one out if there's any chance the coil pack/spark plug unit that I pulled could be tested independently (ie, without messing with any of the other "good" ones).

Does anyone know if that can be done?

I would take what Steve T recommended and take it a step further by moving the plug and the coil pack to different cylinders to isolate whether it is the plug or the coil.

Since you have the Durametric tool, you should be able to read the freeze frame data that was captured when the CEL came on (especially for misfire faults). If you can retrieve this data, please post it as it can help us help you. I'm particularly interested to see how the fuel adaptation is working.

Regards,
paul...

[boxster_s_boy_34]

Originally Posted by Frodo

Thanks, I'll do that...soon as I find me readin' glasses!

This is the problem with most boxster owners; they're old enough to have boner problems and poor eye sight.

[Frodo]

Originally Posted by boxster_s_boy_34

This is the problem with most boxster owners; they're old enough to have boner problems and poor eye sight.

Very astute observation on your part, young fella...except in my case, you're only half right.

[boxster_s_boy_34]

Very good sense of humor. We should B/S some time, but I go back to Iraq on Tuesday. Also, that's the kind of hard time that I get from my friends even though I'm 24.