Dubber
Hi Guys,
I assume this will be the same problem as some of the other guys have been having with the n75 valve for the GT Sport 1.4 twincharger engine, but I thought I would ask just to see if there is anything I should be looking at.
Anywho, my GT Sport has just had it's second major service (120000km) completed, after which the car has started shunting when under load, but not at the 3500rpm point that most people complain about. It does seem to happen less when the car is cold.
I took it back to the place that did the service a couple of days later and they said they had seen this before and said the turbo was faulty and would need replacing (all $3000 of it), which is why I want to know if there is anything else that needs to be looked at. There was an issue leading up to this service that I was getting a constant error for in the VCDS logs in regards to the n80 valve, which turned out to be faulty wiring.
This had happened once before around the time of the first major service, which I thought was spark plugs because the dealer failed to recognise that they did not have the required spark plugs in stock and did not "get them in stock" till 3 weeks later after I called them a few times, but after the spark plugs being replaced, this problem went away until now.
Any advice that people can shed on this would be greatly appreciated.
Volkswagen Enthusiast
Mate first needs a fault check!!! No point saying turbo needs replacement
It's rare for the turbo to be no good. Many other items are associated with controlling boost pressure so they should be ruled out first. Did the service centre find any faults???
Volkswagen Enthusiast
The N75 fault drops the boost at 3500rpm as it dumps all the turbo pressure to the exhaust (and the S/C clutch disengages at this point). However, it tends to fail in tandem with the n249.
The N249 doesn't report anything in to VAGCOM and the only way to know it has failed is to address it directly and run a diagnostic. VAGCOM will tell you the N75 is dead though.
In my GT, the N75 was replaced and it didn't fix it until the N249 was replaced on a second visit.
Get the dealer to directly access and run diagnostics on the N249 before agreeing to any other work.
MY08 Mk5 GT Sport - sold
MY14 Tiguan 118TSI - sold (Mazda3 SP25GT in its place)
MY16 Golf 7R: sold (Caterham Super 7 and Hyundai i30N in its place)
Super Moderator
VWwA Super Moderator
It's always good to seek a second opinion.
Performance Tunes from $850Wrecking RS OCTAVIA 2 Link
Dubber
To be honest, not sure. The guy had taken it for a 20min drive before coming back and proclaiming the turbo was at fault. Was going to get a mate who has a VAGCOM to have a look and see if there actually are any fault codesOriginally Posted by grtuned
Dubber
Rightio, I will see if the guys who did the service can do that for me
Volkswagen Enthusiast
Has the N75 been replaced before? If not it'll most likely have the original design. VW updated the design to use a different diaphragm which works much better and has less chance of failing and doing weird stuff.
MY08 Mk5 GT Sport - sold
MY14 Tiguan 118TSI - sold (Mazda3 SP25GT in its place)
MY16 Golf 7R: sold (Caterham Super 7 and Hyundai i30N in its place)
Dubber
As far as I am aware it has not been replaced. I guess doing 70000km's+ in 2years will expose issues in a 7 year old vehicle...
Volkswagen Enthusiast
My hunch would be that it's more likely to be the N75 and N249 combination than a failing turbo (I'm not a mechanic).
MY08 Mk5 GT Sport - sold
MY14 Tiguan 118TSI - sold (Mazda3 SP25GT in its place)
MY16 Golf 7R: sold (Caterham Super 7 and Hyundai i30N in its place)
Dubber
That would be my guess as well...
Reply With Quote
Bookmarks