Fluctuating boost!!?

[V5 MAN]

Just found a new fault on my scoob tonight.

the scenario:

5th gear, 70mph, 2800ish rpm.

floor the accelerator and the boost goes up to the mapped 1.2 bar, then drops to 0.9, then fluctuates up and down from 1.2 to 0.9 bar.
The revs are not affected by this, im just watching the boost on my gauge and can feel the car boosting, then losing boost, etc etc

Any ideas? Anyone know the symptoms of needing a boost solenoid + pipe clean out? or is this the symptom of a boost leak?

ta for any advice :love0030:


Cliff

[Olly P]

Doesn't sound like a leak.
I think it would read 0.9 all the time if it was leaking.
Could well be the solenoid pipeing, or a soft actuator, or a problem with the map.
I would get it checked out asap as its boosting to 0.9 but fuelling for 1.2 which will be very rich.

[Agent Smith]

mine did same once...........found it was the turbo timer.....

[V5 MAN]

FYI, it turns out its the ECU not liking the extra boost its seeing, its mapped for 1.2 bar but actually running 1.35 bar now. WHY? because I took the cat out of the up-pipe and haven`t had it remapped since!!! :innocent0009:

So, the answer, increase the size of the hole in the restrictor coming off the compressor housing.

Its all clever stuff eh?! :cool:


Cliff