MK5 Golf GTI

All Things Mk5 => How to Guides / Troubleshooting => Topic started by: Ash_89 on April 02, 2021, 08:52:54 pm

Title: Spark plug colour
Post by: Ash_89 on April 02, 2021, 08:52:54 pm

I have been getting a misfire/spluttering on wot recently, the throttle turbo pipe is also potentially leaking at the seam.
I’m assuming the dark plug is from carbon fouling as the plugs before Xmas were all uniform in colour
Plugs Ngk bkr7eix
Ko4 tfsi
Stage 2+

(https://i.postimg.cc/MTDgpLcR/A137-A025-8-F8-D-4809-9-C5-F-953206-E5-EAD3.jpg) (https://postimg.cc/R6WgPXLV)

Title: Re: Spark plug colour
Post by: pudding on April 03, 2021, 11:13:05 am

The left one could be a bad injector, dribbling rather than spraying.  Quite common.  The other 3 look normal.  The white crusties look like ash deposits from burned oil.

Title: Re: Spark plug colour
Post by: Ash_89 on April 03, 2021, 11:42:16 am

@Pudding (https://www.mk5golfgti.co.uk/forum/index.php?action=profile;u=10733) Funny enough I was going to send the injectors off to Aks tuning within the next few weeks, fitting a new set of BKR7EIX plugs today aswell.
3 out of the 4 injectors are original from new so they have done well to last 2 years at stg2+.

Title: Re: Spark plug colour
Post by: pudding on April 03, 2021, 12:09:13 pm

Try running a few tins of LiquiMoly injection cleaner through it mate.  That stuff totally cleared up a stumbling idle and part throttle on mine.

Title: Re: Spark plug colour
Post by: Ash_89 on April 03, 2021, 01:03:00 pm

Yeah I’ve seen a few company’s doing gdi injector cleaner

Title: Re: Spark plug colour
Post by: Ash_89 on April 12, 2021, 12:06:42 pm

Injectors came back from Aks tuning Saturday morning, Cylinder 2 wasn't flowing as good as the rest so needed to be replaced to get the best out of the set.
I also de-coked the valves over a few days replaced the fuel filter and spark plugs, now the car feels more smoother to drive and starts slightly better as well.
Looks like I will be repeating/checking the valves in the next 10k from now on.

Title: Re: Spark plug colour
Post by: pudding on April 17, 2021, 03:08:04 am

All good diligence there  :happy2:

I had a bad injector cause a dead misfire at 80K, so I just replaced all 4 because, well, why not.  It's a ball ache removing the intake manifold and once one lets go, the others will follow.

These engines totally rely on the injectors for mpg and smooth running, but the harsh nature of GDI kills them off, especially on short journeys.