Hi ohh knowledgeable forum

I have a rebuild 90´T2 - NO mods at all - running smooth as silk.
Problem is that i hit fuelcut whenever going WOT, though if i feather the throttle it will build up pressure and hold a steady 7psi all the way to the overrev buzzer.
Please help me out

I've checked:
Boost solenoid
Wastegate actuator
Replaced vacuumhoses
Checked for leaks
CAS

Thanks
- Kim

 

Air flow meter ?

 

My guess would be the boost sensor itself. If you know the exact psi, then I'm guessing you're reading off a separate gauge. Find someone with a known good boost sensor and swap them, see if the problem disappears. Something is telling your ECU that you're overboost and the only thing in that system that can do that is the sensor.

 

Airflow meter is only a few years old.
I'm leaning towards the actuator itself, will check the boost sensor too.

 

Kim, do you have aftermarket boost gauge? Do you actually get boost spike ?

Recently, we had more than one FC having problem with dual voltage fuel pump setup not working correctly, ie, it did not switched from low to 'normal' (you can measure that at the fuel pump power wires). Switching to permanent 'normal' voltage fixed problem which otherwise was very similar to fuelcut symptoms...

 

I use a super accurate industrial vacuum/pressure gauge(switch)

ZSE30A, Digital Pressure Switch, 2 | SMC Corporation of America

Fuel cuts at 8,6psi and sometimes i see a 10psi reading.

Will check pump if actuator turns out to be ok

Thanks

 

Oh, from the way you described it before, it sounded like you weren't over boost, but that you were getting fuel cut. This is a whole different situation...the default position of the wastegate actuator is so that the wastegate is closed and building boost. If your vacuum hoses to the actuator are leaking (old factory rubber, etc) then the actuator doesn't see the boost to allow it to open the wastegate and stop the production of boost.

Short answer: check your vacuum lines to the wastegate actuator.

 

Wastegate vacuumhose.
Hate turbos, love the boost. :-D

 

I win! LOL

 

"pads blacks shoulder"