Boost turns into the vacuum under load. Why?

[cesanneo2]

Hi.
My boost reading through the app is generally 5-10 psi.
Under acceleration and 3k+ revs it reaches 20 psi and then I have the sudden vacuum on the meter.
No black smoke (at least nothing so bad I could see any dark clouds through my back mirror).
I would expect the pressure to build to 20 psi and if overpumped I would expect the wastegate action to be swift and observe small drop maybe, no vacuum. Should it work how I think it should?
Did you experience something similar - positive boost pressure turning to vac under quick acceleration? If I accelerate slowly it never boosts to 20 psi but also doesn't turn to vac.

cheers

 

[tweak'e]

check for pre turbo intake hose collapse. one of the d40 version was prone to that. that can also happen with blocked up filter/snorkel etc.

 

[MANNING]

Are you using "Torque"?

 

[cesanneo2]

Are you using "Torque"?

Yes. The readings come from torque app (Bluetooth odbii).

 

[MANNING]

If you go into the app
Long press your boost gauge
Click display configuration
Set minimum value
Either make that value 0 or 1
You could also make your max value 25 or whatever works best for your display

I have a gauge wired into the car
It doesnt jump around like the app used to before doing those things.
If the value gets changed back it will still jump around..

I don't believe you have anything wrong and that it is just the app not entirely reading your car

 

[Brad20v]

This is good to know i use Torque app and my R51 does similar, it hits full boost them violently goes boost -vacuum, but no change in the way car runs.

 

[loempoer]

If you go into the app
Long press your boost gauge
Click display configuration
Set minimum value
Either make that value 0 or 1
You could also make your max value 25 or whatever works best for your display

I have a gauge wired into the car
It doesnt jump around like the app used to before doing those things.
If the value gets changed back it will still jump around..

I don't believe you have anything wrong and that it is just the app not entirely reading your car

wow, i have similar issue on my d23 yd25 , the boost gauge on obd when full throttle sometime jump to negative, i dont feel any different on the performance

its max out at 1.5bar then sometime jump to -1.0 bar several time.. i dont feel any jerky or issue

i tried several other apps.. torque, motordata,car scanner etc, and several obd adapter all those show similar result..

i though its bad boost sensor, glad to hear its only a glitch and happen on other navara