MK5 Golf GTI

All Things Mk5 => Mk5 General Area => Topic started by: ZoliWorks on May 01, 2025, 09:47:32 pm

Title: Cylinder 3 misfire at idle and WOT
Post by: ZoliWorks on May 01, 2025, 09:47:32 pm

2.0 BWA stage 3 k04. New OE injectors. Constant misfire at idle, very rarely in second gear, very often in 3rd (both at WOT and when driving light) with CEL and never in 4th or higher.

Spark plugs and coils swapped, still misfires on 3. Tried OE spark plugs and coils, still misfires on 3.

Parts replaced ~2 months ago:

• New OE injectors
• New Hitachi (Hüco) HPFP with Vis stage 1 internals
• New Continental LPFP
• New OE fuel filter
• New OE FPRV
• New Bosch MAP
• New Bosch rail pressure sensor

Compression measured with the engine warm 13.6 - 13.0 - 13.2 - 13.5

The errors in VCDS say random misfire and misfire on cyl 3 and 4
The attached picture was taken after I took the car for a hard spin and let it idle. Misfires at idle intensify a lot after spirited driving.

VCDS logs 4th gear WOT

https://docs.google.com/spreadsheets/d/1l6Z3tEsAvtinR4PQWmCqf2nsFLjH6blG/edit?usp=sharing&ouid=118073874432582966130&rtpof=true&sd=true
https://docs.google.com/spreadsheets/d/1w4mLitR5x1-YkMhTStyqGs9hkNw5YIyA/edit?usp=sharing&ouid=118073874432582966130&rtpof=true&sd=true

(https://i.postimg.cc/5yHWZVDC/misfire.jpg) (https://postimg.cc/jnr17Gxx)

Title: Re: Cylinder 3 misfire at idle and WOT
Post by: ZoliWorks on May 02, 2025, 12:07:10 am

There's a lot of carbon buildup which i'm cleaning next week but this doesnt quite explain the misfire in 3rd gear under normal driving or WOT.

(https://i.postimg.cc/76YYBbDP/carbon.jpg) (https://postimg.cc/7CdkhHfj)


The intake camshaft is also a bit worn. Maybe too worn out? The car has always had slight misfires at idle, especially after hard driving.


(https://i.postimg.cc/W4s23tdm/Whats-App-Image-2025-05-02-at-00-28-32-b887dd28.jpg) (https://postimg.cc/dhSMNsmD)

(https://i.postimg.cc/52B4b82N/Whats-App-Image-2025-05-02-at-00-28-32-d8ca114c.jpg) (https://postimg.cc/qN7VGhK9)

(https://i.postimg.cc/02J5XTgS/Whats-App-Image-2025-05-02-at-00-28-33-ad3813f8.jpg) (https://postimg.cc/svsRv0gf)

(https://i.postimg.cc/CxTh3cYQ/Whats-App-Image-2025-05-02-at-00-28-33-e253adcd.jpg) (https://postimg.cc/Tp0vmqKV)