Mk5 Golf gt 1.4 TSI (170) turbo issue

[Ludlow_dweller]

Hi All,

Not sure if this is the right place to post this as I am new?

My son has bought a 58 plate tsi with 49,000 miles on it, it has ran great but now when he floors it the turbo seems to drop out after 2/3 seconds and the turbo gauge drops to half on the dial. It does not happen all the time though. Has been back to the garage and had a new solenoid valve fitted but the same issue happened within 1 day.

Any help would be appreciated.

[Crasher]

We could do with knowing what they changed solenoid wise as there are two that apply to this. One job we have to do a lot on these (one last Friday) is the turbo boost recirculation valve as they split. The results of a fault code read would be very helpful as well. Does he get any odd "clacking" or "squealing" noises under acceleration?

[Ludlow_dweller]

Crasher,

No EMU light and no fault appears on the diagnostic machine, the garage it went to told him it was because he put normal unleaded fuel in and not super unleaded by mistake?

I will get the number off him for the valve and put it on shortly

Thanks

[Crasher]

It is quite normal to not get the engine MIL come on which a problem like this, it will tend to only come on due to an emissions error. The one we did on Friday did have a code on the ECU but no light. Do you have the equipment to read the ECU for codes? Running them on 95RON causes a loss of power in certain situations and it is not ideal to run them on 95 but the symptoms you describe are too severe for this to be the problem.

[Ludlow_dweller]

Valve part no on the box is as follows: 03C-145-710-E

[Ludlow_dweller]

No equipment to read the ECU either I'm afraid

[Crasher]

Yes, that is the N249 valve with is prone to failure and what I was referring to. It is going to need some more in depth work to find out the problem. A common problem is the supercharger magnetic clutch.

[Ludlow_dweller]

Crasher the issue seems to be happening on higher revs I thought the supercharger was low down revs etc?

[Crasher]

Yes, it is. It is going to need some diagnostic work using something like VCDS to watch the boost tables and also possibly a charge air system pressure test to check for leaks.

[Ludlow_dweller]

it is under warranty at the moment so I think its best to go back and let them sort it then.

Thanks for your help