I recently got a vaccumm gauge for my lude and I noticed that it rests at like 7.5 when the car is off. Correct me if I am wrong but isn't it suppose to be at 0.

 

when the gauge looses power, it probably goes limp (assuming its an electronic gauge)

 

the only problem is that it is a mechanical gauge

 

Yes, a mechanical gauge should read zero with the engine off.

 

what brand of gauge is it? perhaps the gauge isnt functioning right.

 

what happens if you unplug the gauge? does it go to 0 when the port on the back of it sees atmosphere? if not, it's screwed up. if it goes to 0 when it's exposed to atmosphere, but not when you turn the car off, perhaps it's plumbed into something where the pressure doesn't equalize. not sure where that would be, but a thought.

 

its an Autometer gauge and it read something like 7.5 when car is off or if the hose is dissconnected from the unit.

 

return it, it's F-ed. my autometer reads 0, or within a tiny smidge of it.

 

Went back to NOPI and I have another on the way, thanks