Hello ,

i had some trouble last week with my 997.2 GT3 .
while on the track , i’ve got a check engine light and misfire at 4/5RPM.
the CEL disappear and came back several Time during the trackday , then it remains at the end of the day, the car runs pretty well excepted the misfire and a lack of power

Once back at home ,i checked the Code : P0305 : missfire Cylinder 5
the symptom looks like a bad coil ignition .
so, i changed it without checking the spark plug.( spark changed 2 years ago and runs 10000kms , while coil are at least 6 years old and 40000kms)
I cancelled the CEL , then went out for a ride and after 5 minutes it came back ( CEL&misfire)
i checked the Spark Plug ... and found that :



the spark on the right has lost a small part ( the white part on the left one)...

so, i’m a bit worried , if this piece has been into the cylinder i may have some big trouble with the Mezger.
i changed the spark plug , and now the engine is running perfectly... no misfire no CeL ...no lack of power.

I need your help & advice:

What could be the reason of that issue with one spark plug ?
If the coil was sore, and i keep using the car , is it possible that it has destroyed the plug ?
i Mean, is the source of the problem the coil, and the conséquence the spark ?

other thing maybe the most important ... the engine may have been damaged ... but if it is running well now ... can i feel sure that there is no damage ?

many thanks

 

Is there an update to your issue? I saw the same thing happen to a member on rennlist and unfortunately it caused cyl and piston damage as I recall. I believe he had that cyl repaired. The question is, how did that piece of porcelain break off...? In his case, as I remember, the plug fell on the floor and that caused a crack on the porcelain, then the failure.
You may have gotten lucky somehow, but I'd get a leak down test, and maybe a camera in there to see if there was damage-

Best, JB

 

Actually, we did the test with the camera then the leak test and no issues so far.

my indy says that In most of the case, there is no damage, because the porcelaine is In reality a powder. This is rare , from his experience, to have a damage on a N/A engine.
regarding the other spark conditions, he told me the same thing , the spark has probably been damaged before

once the spark has been changed , engine is working perfectly.

if you have the link of the rennlist topic , i will have a look... i’m still surprised i’ve been through this situation with out any trouble 😁

 

It looks like in your case you got lucky, and just the porcelain. In his case, the porcelain and the center electrode dismantled and the electrode caused the damage:

https://rennlist.com/forums/997-gt2-...ure-found.html

Best,
JB