GT Sport TSi Issue

[MY08GT]

G'day folks

I'm having a frustrating issue with my GT Sport. It's the 1.4 Petrol TSi variant. I'm not an auto-buff so please be patient. As you all know there's a boost gauge on this model, which depending on throttle position indicates supercharger/turbo pressure. So, when you are at full throttle or you're in a gear that requires a bit more power it generally goes to full boost. Recently I've noticed that the power is intermittently greatly diminished. For example, I was accelerating up a hill in fourth gear, the supercharger initiated, gauge went to full boost, and then all of a sudden, despite my foot being flat on the accelerator, I felt a significant drop in power, and noticed the boost gauge fluctuating at around mid-point. This problem is not consistent, for example I'll drive up the same hill, 4th gear, flat on the accelerator and the boost will stay 100% until gear change is required. This afternoon I was on the freeway, 5th gear, 100km/h, there was a bit of traffic which slowed to 80km/h and then when traffic cleared when I attempted to accelerate I had the same problem where boost initially increased and then despite full-throttle dropped off (boost hovering 1/3 to 1/2) and I lost power.

Note, the vehicle has travelled ~3800kms, and I was very careful at running it in properly. Premium unleaded every time. Any comments and advice would be highly valued and greatly appreciated.

[Mischa]

Note, the vehicle has travelled ~3800kms, and I was very careful at running it in properly. Premium unleaded every time. Any comments and advice would be highly valued and greatly appreciated.

another member here had a supercharger failure and had to have it replaced. i hope by running it in properly you mean you drove it hard, and not that you babied it?

welcome to the forum btw

[Logzy]

i hope by running it in properly you mean you drove it hard, and not that you babied it?

x2, drive it HARD.!!!!

Take the car into the dealer (unfortunatley) and get them to look at it.

[pra32]

i hope by running it in properly you mean you drove it hard, and not that you babied it?

hahahaha classic

[mrx]

If it starts off boosting and then dies, it's almost like when the supercharger cuts out the turbo charger isn't cutting in. Boost leak on the turbo side of things?

[MY08GT]

If it starts off boosting and then dies, it's almost like when the supercharger cuts out the turbo charger isn't cutting in. Boost leak on the turbo side of things?

It seems to lose power earlier (i.e. <3000rpm) than the "swap-over". I actually just got back from the VW-Service department. Frustratingly, as expected, we couldn't reproduce it with the mechanic. However he popped it onto the computer which promptly informed him that there was no logged issue. The mechanic, who was very helpful, suggested that it could be a fuel issue, and recommended I run the tank practically to empty and fill up from another servo and see how I go, so this is my next step. Any further recommendations from this forum are very much welcome.

[warhead]

I think something similar happens in my TSI as well, but I haven't found a nice stretch of road where I can really hammer it.

My boost goes up to about half and then falls flat, but I'm just accelerating normally here.

And does the gauge shows the boost pressure of the super charger or turbo charger or both?

A bit OT, but what's your average fuel usage when going a tad hard?

Mine does about 7-8.5L/100K if I drive normally, if I get a little excited with the pedal, then about 9.5-10L/100K.

[BarneyBoy]

Twice I've had what I can only describe as no supercharger boost at all - no supercharger sound, no boost on the dial, and very slow acceleration until 2500rpm when the turbo finally delivered some boost.

I pulled over both times, switched off the motor, started again (attempting to duplicate the problem) and it was all AOK again.

It hasn't happened since then and I'd forgotten about it til I read your post.

Like me, you're probably reluctant to see your dealer, but their diagnostics should log a fault like yours. Since the two blowers are electronically controlled, they will log faults and 'issues'. On the first day I had mine, it went into limp home mode, limiting it to 3000rpm. The log revealed that the 'brain' thought it detected some fault in the AirCon, triggering the LHM. A reset fixed it. Apparently the electronics aren't infallible, erring on the side of caution instead. And sometimes they don't get it right.

Probably would be wise to book a time for your stealer to look at it and give you a rundown of the dump from the 'brain'. Other than that, I hope you're enjoying your GT!

[mikinoz]

Dealers should get codes from ECU if there has been supercharger failure/incorrect operation.

Ask them?

If it is common and can be replicated, maybe take them out in it?

[MY08GT]

Thanks for all your feedback. Mikinoz, the brain-dump was performed last week at VW and no faults were detected, and we couldn't replicate the issue during a test-drive. The mechanic suggested it might be a fuel issue. I refueled with BP Ultimate this evening after going as close to empty as I could dare (53.5L) as recommended by the VW-mechanic. I will monitor performance and keep you all posted if any further issues arise.

[Reyne]

Hi guys,
Been reading through the forum for a while now. Its a great resource for new owners like myself and my thanks go out to evryone for all of the useful info on here...
I thought I'd make the first post a useful one.

MY08GT, mate I have had the same issue as you describe above. I took the car into the dealer today to see if they could sort it. Apparently it's an issue fixed by a simple software upgrade. I haven't picked the car up from them yet to confirm its worked but I'll let you know how it pans out.
For the record, my car specs are as follows:
MY08 Golf GT Sport TSI, DSG, Sunroof, United Grey, Latte Leather.
It has about 6000km's on the clock at present... the above problem kicked in at about 5500kms.

On another note, I've also noticed a rattle coming from somewhere up front. You can only hear it if it quiet inside and the car is warmed up.. It's most audible when driving slow speed. maybe into a carpark or something and at low revs. You can also hear it if you put the car under some load at low revs like going up a hill in a high gear. I highlighted the prioblem with the dealer today and got the "all gt's do that" response... Needless to say, I dont believe him.
Anyone have any idea what this might be?
The DSG or the supercharger are on my suspects list....

[Mischa]

apparently theres a design fault that all gt's and gti's have a rattle from the centre vent on the dash which can be rectified by putting some padding in there. heard this from william (ex vw tech).

[MY08GT]

I've only had one recurrance of the problem, which occured straight after refueling. Since then the issue has not reappeared so until your (Reyne) response I assumed the problem fixed itself with better quality fuel. Let us know how the software upgrade works out Reyne and I'll give my dealer another call ...

[Reyne]

Hi guys,
The software upgrade has definately worked.. The service center (Austral VW in Brisbane) has had quite a few in with the same problem.
As for the rattle... managed to sit the service rep down in the car and demonstrate the noise. Turns out its the exhaust slightly misaligned and rubbing up against a heat shield. It only happens when the engine is warm, under load in drive and it flexes on its mounts.

[Greg Roles]

I've noticed my engine rattles a lot.