Boost is faulty and car down on power

Tiny
STEPHENK669
  • MEMBER
  • 2001 VOLKSWAGEN GOLF
  • 138,000 MILES
I have a mk 4 vw golf 1.9tdi 90bhp and my boost is faulty and the car is down a bit of power. The turbo wont boost until I reach 2500 rpm and after that.

vw golf mk 4 90bhp
engine code alh
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Saturday, August 18th, 2012 AT 1:49 AM

2 Replies

Tiny
KHLOW2008
  • EXPERT
Is the MIL indicating?
Check for leaking hoses between the turbo and engine. If no leakages found, check the turbo unit for failure.
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Saturday, August 18th, 2012 AT 6:20 AM
Tiny
EXOVCDS
  • MEMBER
This is a simple system to diagnose... but not so easy to explain over
the internet / via a keyboard.

First, you need to make sure that the intake manifold is not plugged
up... causing lack of air to enter the engine.

Remove elbow hose at the top of the engine to have a look...

If the intake is clear, you need to check for proper movement of the
turbo vane actuator / rod (at the back of the engine, best viewed
from under the engine/car).

http://www.youtube.com/watch?v=cGRsgYAE-CI

As soon as the engine is started, the actuator rod should be "pulled down"
which causes the turbo to spin faster (boosts quickly).

Once the engine computer measures enough boost, the rod is released
which slows the turbo spinning / lowers boost.

When the vanes get "stuck", the turbo does not spool quickly and
the engine feels low on boost.

When the actuator rod does not move... the "vacuum source" to the
actuator pod is bad (low vacuum, broken vacuum hose), the vacuum
solenoid is bad, the actuator is broken, or the vanes are stuck.

Thomas
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Saturday, August 18th, 2012 AT 6:26 AM

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