The stock boost guage reads about a half centimeter below zero when the key is in the on postion with the engine off. At idle and cruise it sits at pretty much the bottom below the 20 mark. It seems to move upward with the boost just fine, just not sure why it reads below zero with the car not running. Maybe I need to clean something? The vacuum line appears to have been replaced and there is probably not a little pill in there, but that should not affect readings when the car is off. The only modification done to the car is a catback.

 

what reading do you expect from a powered (read electric) boost sensor when the car is off? Its certaintly not going to be "0"!

 

With the power on and the engine off it should read 0, because there is 0 vacuum.

 

Theoretically yes, but I dont even think mine does it. But I see what you are saying.

 

The needle could of just moved. I bumped my volt gauge and it read 2 volts higher than it actually was. It happened when i was changing gauge faces. Just take off the plasitic cover and move it to zero.

 

you could have a vacume leak. im not sure what the stock boost gauge looks like anymore because i never look at it(got aftermarket). but i know when i get vak leaks it will drop. but when the key is off or at idle it should sit in the blank spot