Golf 118 TSI Engine - Revised Spark Plug issued

[gavs]

Well that information is contrary to everything else I have seen, read and measured so I'm not so sure that the updated part number is in fact the correct updated part number in Australia, I really don't know why they would be the same length.....

The whole point of shortening the spark plug was so it was no longer wet with fuel which was one of the leading causes of the misfire issue in the 1.4tsi, if people have a VCDS and hook it up, under the live viewing section you can actually see the car continuously logging misfires when warm.

A shouldn't be platinum either, both should be iridium, A was factory fit to the polo GTI and is an iridium plug according the service department!

Shouldn't be surprised when it comes to VAG though, saying one thing and the truth being vastly different....

[blower]

Well that information is contrary to everything else I have seen, read and measured so I'm not so sure that the updated part number is in fact the correct updated part number in Australia, I really don't know why they would be the same length.....

The whole point of shortening the spark plug was so it was no longer wet with fuel which was one of the leading causes of the misfire issue in the 1.4tsi, if people have a VCDS and hook it up, under the live viewing section you can actually see the car continuously logging misfires when warm.

A shouldn't be platinum either, both should be iridium, A was factory fit to the polo GTI and is an iridium plug according the service department!

Shouldn't be surprised when it comes to VAG though, saying one thing and the truth being vastly different....

I've never heard that the genuine VW ones were shorter - only that shorter was recommended for the reason you state, to stop the fouling of the plugs with the wider spray pattern of the newer revision injectors that came out in 2010.

Around the net it is recommended to put in NGK BKR7EIX plugs - which are noticeably shorter and also one step colder.

VW have 3 versions of plugs in these engines:

101905626 - 0.9mm platinum tips
03C905601A - 0.8mm platinum tips
03C905601B - 0.8mm iridium tips

Heres a shot of all 3 from left to right, these are genuine plugs pulled out of my engine over the years....the part numbers match the data history for CAVD engines on ETKA:





All 3 the exact same length and the iridium tip can be see (its slightly thinner than the platinum tips).
I'm now on NGK BKR7EIX, put in after changing all the injectors out for the newer revision ones (03C906036M).

There are 3 sets of injectors in CAVD/E engines too:

03C906036F (factory up till mid 2010) - Narrow spray pattern, less efficient air fuel mixture causing unburnt fuel to pool on piston crown.
03C906036M (mid 2010 onwards) - Wider pattern, suspected to foul plugs.
03C906036N (2012/13 onwards) - used only in CAVE or CTHE engines, unknown what the difference is at this point.

I believe there are batches of faulty injectors out there that have gone unrecognised by VW. I know there was a recognised batch of faulty injectors from 2009 - but i believe some of the newer 2010 and 2011 ones have faulty batches too. The faults ranging from leaking injectors or incorrect flow. I bought a set of 2011 2nd hand injectors off ebay and had them ultrasonically cleaned and tested....when put in the car all 4 were badly carbon fouling the plugs, and at least one was confirmed leaking under high pressure (despite testing saying they were leak free). I replaced them all with brand new injectors of the same part number and there is no fouling of the plugs - even the genuine VW plugs that are not short, didn't foul.

I have a hunch that there are faulty injectors out there that are fouling sparks when they shouldn't be, and switching to a shorter plug such as the BKR7EIX is alleviating the issue. None of my plugs have ever fouled with the original injectors nor the replacement brand new ones - just this one batch of 2011 ones did, and i suspect the recognised batch from 2009 also foul the factory plugs.

I never had misfires on 03C905601A or 03C905601B (logged with live counters on VCDS), the bigger gap 101905626 did misfire slightly though but it is known the gap for these plugs should be 0.7 - 0.8mm.

[ope126]

Mate that is a detailed post there, thanks for that!
I am sure that will help others if they ever need it.

Also, thanks for the part numbers on the injectors also - that will come in handy!