MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: DarlyN316 on August 24, 2022, 06:42:20 pm

Title: Misfiring
Post by: DarlyN316 on August 24, 2022, 06:42:20 pm
Good Evening. Can anyone help me troubleshoot my GTI's behaviour. On Sunday morning it suddenly started misfiring. When I did a diagnostic test it gave me the errors in the images attached. So I removed the spark plugs and the one in cylinder 1 had partially melted. I replaced the spark plugs tried to run the engine but the problem didn't go away. I then returned the old spark plugs with the exception of the melted one which I replaced with one of the newly acquired ones. when I removed the one in Cylinder 1 I noticed some engine oil on the spark plug. It wasn't alot but it was wet with engine oil. What could be the possible cause of this problem and how do I go about to arrest it? (https://uploads.tapatalk-cdn.com/20220824/9ab21e0096cca301b310114130bed13e.jpg)(https://uploads.tapatalk-cdn.com/20220824/b88f72776556bd9f1447b84ecd88adca.jpg)(https://uploads.tapatalk-cdn.com/20220824/9ad60279679c46fd6515553cf8c32a90.jpg)

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Title: Re: Misfiring
Post by: pudding on August 24, 2022, 07:44:46 pm
Only severe detonation can melt a plug like that. If the new plug is oiling up very quickly, the piston has also been damaged. Maybe get a camera in the cylinder and check the outer circumference of the piston for chunks missing.

What’s with the orange plug? Looks like octane booster has been used?
Title: Re: Misfiring
Post by: DarlyN316 on August 24, 2022, 08:29:14 pm
The orange plug I am not too sure. I have never changed them since I got the vehicle in 2018. They should be the originals from the manufacturer. They are still labeled VW. I will try to split it up over the weekend.

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Title: Re: Misfiring
Post by: GilesWoodward59 on August 25, 2022, 11:17:59 pm
+1 for octane booster cause