Another overboost and fuel cut post

ArchieBrown · Post by **ArchieBrown** » 21 Apr 2013, 22:18

Hi,

850R manual with 90K miles on it - and I've just got back from a weekend in the mountains. About a week ago I turned the wastegate actuator 4 half turns tighter (two full turns) and took it for a drive. Awesome.

But just recently its developed some symptoms:

1 - Extremely fast - heavy torque steer fast.
2 - At WOT boost gauge would go off the scale to the right - but now is non-responsive (stuck in middle).
3 - Under acceleration I can hear a quite audible whistle.
4 - Past 3500 or so, pulling hard, the car will occassionally halt/stutter which sounds like a fuel cut.

These symptoms only exist when its floored - the exception being the whistle.

I like the whistle, the viscous acceleration, everything except the fuel cut and the boost gauge not working.

I've seen a bunch of posts on the matter - but I wanted to get some fresh eyes on it.

What are your thoughts?
Four half turns is too much?
Hoses need replacing?
What is the potential for damage?

As always, thanks.

Arch.

Post by **burnout8488** » 22 Apr 2013, 01:21

The wastegate is too tight, and it sounds like the extra boost has created a boost leak. Check the throttle body hose, they usually split.

When the wastegate is too tight, the boost control solenoid can't effectively pull back boost, and the car ends up spooling too quickly and building too much boost.

Post by **jblackburn** » 22 Apr 2013, 08:23

Check your vacuum lines to the turbo control valve. I think the red one to the underside of the turbo is broken.

ArchieBrown · Post by **ArchieBrown** » 23 Apr 2013, 01:09

Thanks gents.

If it is the vacuum lines - and I fix them, am I being an idiot to hope that the awesome boost and assosicated whistle will remain (without bending all my rods)?

Arch

Post by **jblackburn** » 23 Apr 2013, 10:32

ArchieBrown wrote:Thanks gents.

If it is the vacuum lines - and I fix them, am I being an idiot to hope that the awesome boost and assosicated whistle will remain (without bending all my rods)?

Arch

It shouldn't be boosting as much as it is. Under uncontrolled conditions, a single event of knock in hot weather or on poor quality fuel can cause permanent damage.

When you get it running right again, look into a tune for that extra power you'll be missing