When you turn your key to the on position, without cranking the car. what does your boost gauge read? Once you you start the car and youre idling, what should the boost gauge read? I assumed that when the motor is off and the ignition is on, that the boost gauge would read zero, but mine does not. is something wrong? Just curious what everyone elses says.

 

Nothing happens with mine. Once she is started, then she reads vacuum. I want to say around 20 at idle. I'm not too keen on the gauges themselves, but my guess would be a faulty gauge because you should be reading zero with the car not running and the key in the on position. How long have you had the boost gauge installed? If it's been on for a while and just started doing this, I'd say you have a faulty gauge. Oh, and I'm assuming this is a mechanical gauge right?

 

Mine returns to zero when I shut the engine off, so that's what it reads with the key on.

You will get different idle readings depending on if the engine is at operating temp or not.

 

Mine is the Prosport gauge that Alta sells. Its electronic. Unfortunately I never took notice before so I dont know if its always been off or if it is something that just started recently. my peak PSI used to be around 16, now its 15. I've changed belts, twice, and cleaned my intake just trying to figure out where my 1psi went. I just happened to notice today that with the motor off it reads -1 or 1 vacuum (just below the zero). This may explain my 1 psi loss if somehow the gauge became uncalibrated....if thats even possible? Hopefully someone with a prosport can confirm what theirs reads too.

 

I have the same gauges, when the key is in the on position with the engine turned off it reads zero and when the engine is on it reads around 20 vacuum like partsman. I have a 15% pulley and I usually hit around 15.5-16 psi max and once 18

 

=1^

Prosport guage. Sounds like you may have to return it if it is reading -1 when engine off.....

In cold weather, my guage needle sticks and doesnt move....I have to tap or "flick" the bezel with my fingernail like the older guages in some air planes.....

I would return yours or contact company directly in FL. They are a great group of guys down there, a very helpful crew.

 

It should read zero. I have mechanical Autometer gauges for boost. They are reliable and accurate as long as the connections are leak free. Less electronics is better sometimes.

 

well thats great news actually. I'd rather have a gimpy gauge rather than lose 1 peak psi somewhere. Sad thing is, I have had nothing but trouble from this gauge. It rattled, one of the plugs on the back was faulty and wouldnt illuminate in amber.(luckily there is an extra plug for piggybacking, but I may be in trouble if i get another gauge)