So, I'm prepping everything to install my boost gauge when I noticed that the gauge is at -5psi earlier today it was a lot closer to zero. It's raining now. Is my boost gauge acting like barometer and is the weather affecting my gauge?

I'd hate to install it now and get false readings the whole time. any insight would be awesome.

 

what kind of gauge is it?

 

Weather changes should not affect it.
It should be at zero if not connected.

The standard atmoshpere is at a pressure of ~101,325 pascals at sealevel.
Your gauge reading -5PSI (if we assume your gauge is right and acts as a barometer)
would mean you have an air pressure of ~68,947 Pascals.
Ths means you would have to be at ~3.5Km up in the air to get this reading

 

The post is very unclear. You are either talking about running 5psi or 5in hg?

 

1. It's a glow shift gauge.

2. I noticed the needle on the gauge was pointing at -5 inHg after I mounted it to the vent ring.

3. I didn't know if the weather was enough to change the reading on the gauge. Now I'm starting to think that the gauge is just off and now I have to figure out how to zero it.

 

It should be around 20in hg when warm at sea level. Mine goes to about 18-19in. If it doesnt go any higher when warm, you need to start looking for vac leaks.

 

actually, I was talking about the gauge being at -5 before I installed it. as in sitting on the coffee table. I think I'll get another gauge since I don't think this is calibrated right now. But now, everything's installed. I might have a small leak somewhere but I think I have an idea where.

Now, I did it during the day time and everything seemed alright. I drove it at night and my driver side tail light doesn't work. It lights up though when I turn on the alarm. I might have just loosened up a harness or wire or somewthing while I was down there. hopefully that's it.

Thanks for all the input.