GT Sport TwinCharger Shunting

[piper26]

Hey mate at what rev range is it shunting. You mentioned not around the 3500 mark..
You mentuoned 120 000km service.
Were the plugs and fuel filter definitely replaced? If the plugs were replaced did they move/ dislodge the vacuum lines around coil #4?

Alot of questions I know but just trting to build up the mental image of whats going on. My gt has 140 000km on the clock and is still going strong.

[kane9522]

Hey mate at what rev range is it shunting. You mentioned not around the 3500 mark..
You mentuoned 120 000km service.
Were the plugs and fuel filter definitely replaced? If the plugs were replaced did they move/ dislodge the vacuum lines around coil #4?

Alot of questions I know but just trting to build up the mental image of whats going on. My gt has 140 000km on the clock and is still going strong.

It seems to be shunting around the 2000rpm mark, maybe 1600-2400rpm

Spark plugs were definitely replaced. Fuel Filter, no, I did not think it was part of that service?? I would have no idea if anything would have been moved/dislodged. Further to this though the DSG did have it's service/readaption done as well, silkiest gear changes i've ever had from it since owning it.

And this shunting did not exist before the service, only after. However with the 60000km service it was showing up before hand, then a lot more in between part 1 of the service (stupid dealer "forgot" that they did not have the required spark plugs in stock) and part 2 (spark plugs going in) after which, no issues...

For those following, did manage to get a hold of a VAGCOM cable, and could not find any errors, which is not surprising. We did go for a drive and tried to use the VCDS graphing capabilities to see if there were any noticeable drops in boost or engine load, which certainly did appear.

Is there any harm in getting the N75 and N249 valves replaced??

[piper26]

There is no harm in getting them replaced. Just a cost that may or may not be the cause.. worn plugs and poor fuel supply can cause issues. If there is a fault with n249 then it is usually complete loss of boost

[Mattlock]

There is no harm in getting them replaced. Just a cost that may or may not be the cause.. worn plugs and poor fuel supply can cause issues. If there is a fault with n249 then it is usually complete loss of boost

Interesting. My fault still gave me full boost from the S/C even though the N249 was also at fault. The N75 only failed once the car had warmed up and therefore gave boost from cold.

[piper26]

It seems to be shunting around the 2000rpm mark, maybe 1600-2400rpm

Forgot to mention this range is under supercharger and not the turbo. Faults with n75 or n249 dont rely ahow themselves in this tange as the supercharger is before the turbo.

I can only suggest before you spend money on valves that you buy a fuel filter. Also check the glue rib in the air filter as if this is broken the filter may suck flat 'choking' the engine slighty.

Without driving or seeing the car this is the best advise I can give

[Mattlock]

Faults with n75 or n249 dont rely ahow themselves in this tange as the supercharger is before the turbo.

So for my general understanding, the N75 and N249 only govern the turbo?

[piper26]

Basically yes. Obviously its not a simple system. N75 operates the turbo wastgate and n249 is the recirculation valve (on front of turbo) boost under the charger is effectively governed by the changeover valve to increase or decrease the % of air directed through the charger

[kane9522]

So the more I drive, the less the shunting appears to be happening...

Which would push me towards the gearbox re-adaptation and the gearbox then having to relearn my driving style...