i have an eg with an ls turbo setup. my autometer guage works great to show my boost level but doesnt go into vacuum. i know at idle your supposed to have a certain level of vacuum but the guage never goes below 0 psi. would it be a faulty guage or something else? thanks in advance

 

new or used gauge?

 

Could be, try email autometer about it. They're good at there customer service. I had an issue with my oil pressure gauge a while back. Sent it to them and fixed free of charge, minus me shipping it to them.

 

Sounds like you have it plumbed wrong. Where is the hose connected to?

 

i agree with above^ do you have it connected after the check valve for brake booster? my car had 2 check valves...

 

People still use check valves these days? Ditch those crap and get your car properly tuned. GEEZ people...

OP, tap into the intake manifold. There are a few vacuum lines running into it.

 

^^^ All brake booster vacuum lines have a check valve or the booster has one built into it, this is so the brakes will retain power assist under a load when there is little engine vacuum or while under boost.
You want to plumb the boost gauge directly into the intake mani after the TB for the best results.

 

you might want to reread what he said.

 

my bad....the last time I heard the phrase "two check valves" was back in the days when tuning options was limited.