Golf gti mk5 no turbo power

[schmidt_vr6]

Hi

My mate has a golf Gti and we've been out in it today and at high speed the turbo dies. Feels as tough theres no turbo power. As if we're driving a 2.0 Non Turbo.

It seems to spool upto about 2 and half rpm. Then you feel a little surge and that's it no turbo.

Once you switch engine off it's back to normal again

Any ideas guys?

[dan930]

Will it be a boost leak somewhere?

[th3_f15t]

If the problem is going away upon turning the ignition off I'd suspect there is an electrical system putting the engine into a safe mode. A sensor somewhere might be failing so you'll need to run a diagnostic to see what, if any, error codes are being thrown up. If it was a boost leak you'd get no boost constantly rather than a few times then it going.

[schmidt_vr6]

I've had the car scanned today for fault codes and it's bought up one fault.

PO234 - Boost Pressure Regulation (Overboost Condition)

Any ideas guys?

[Scottymon]

IF you haven't seen already: http://wiki.ross-tech.com/wiki/index.php/16618/P0234/000564

[schmidt_vr6]

Had the car on the ramp, Tried a new Diverter Valve, Problem still there.
Tested the Turbo via Measuring Block on VAGCOM. It just wasn't getting the boost needed. So mechanic said I think the Turbo Vanes are clogged and needs to be sent off for testing.

Anyway whilst removing the Turbo we noticed that the N75 Valve one of the T-Piece had broken and was losing boost pressure causing the engine to go into limp mode.

A new N75 Valve is on order so we think its that what's causing the problem. So I shall report back if the fault is cured. Wish me Luck

[schmidt_vr6]

All Fixed. Was The N75 Valve That Was Shot 

[Dan_FR]

Turbo Vanes!?!?! This is a petrol turbo with an internal wastegate, not a VNT Turbo....

At least it's sorted, you're lucky it didn't cost you a turbo as it could well have blown itself up. Luckily the ECu did its job, realising it had no control over the boost pressure.