When my car is idling, the boost gauge reads 0psi. normal. when i turn my vehicle off and turn it to AC power, the boost gauge will load up and show about 1.5psi of boost. Even from a cold start in the mornings, i'll turn on the AC power and it shows boost pressure. is this normal?

 

When you car is idling it should be reading 18-20 hg of vacuum.

 

Sounds like a bad gauge if anything, what gauge?

 

I have one of those RPD's. and it's on the boost gauge where it will show about 1.5psi of boost pressure when my car is off

 

Oh. If you have the rpd then it doesn't show vacuum.

It's probably normal. Someone with it will probably chime in to confirm

 

Mine shows 0.0 at idle and when powered on but engine off

 

Tmap