Bad gauge or boost leak?

[suicideking]

I have an autometer ultra-lite boost gauge that typically reads -15psi at idle.
When the car is parked and the engine is off, the gauge will sit at around +1 psi.

This doesn't seem normal, but if the gauge was off it'd explain the discrepancy in the reading.

(When I'm in gear with closed throttle decelerating it goes to a nice even -20psi...?)

Any thoughts?

 

[TalonTSi-AWD91]

Your vacuum should be lower when decelerating then idling, that's normal.

 

[spendone]

Yea I sit at 20psi of vacuum at idle.

 

[TalonTSi-AWD91]

Originally posted by TalonTSi-AWD91
Your vacuum should be lower when decelerating then idling, that's normal.

I think I kind of said that wrong. Vacuum should be higher when decelerating then idling. Mine sits around 18-19 at idle and goes to around 24 I think while decelerating.

 

[Astaroth]

My VR4 sits on about 19hg at idle, about 10-15hg at 100kph cruise and my gauge sits dead on zero while she's off.

Autometer gauges are supposed to centre properly, aren't they? Mine does, and I know there's a sticker on the body of my gauge about it not centering properly but I'm not taking the cup off to look at it, it's a pain in the arse of a job

Astaroth.

 

[AL92]

I have a z series autometer 30 to 30 gauge.My car vac is around 15 to 16 at idle.I am at 2000feet above sea level but heard you only get lower vac at higher elevations think over 3000.

So I am a bit low.Its rock steady and haven't checked compression yet to see if its low.Car has 130,000 miles showing on the clock and speedo don't work so might have more.Seems to run fine..no oil out the back,no funny knocks ,etc.

Also I know I have at least one vac leak at tb shaft.Bought seals but haven't fixed it yet.And possbily that my intake manifold gasket is also leaking the old ones were paper there is new improved oem upgrade think its metal.Have to put that in also.

And its common for injectors to get vac leaks at the lower insulator seal.
I switched out to FIC injectors as they elminate the hard factory seals.

My guage seems to be centered ok.So I think I do have a vacuum leak.Another tip is my low trim shows lean with everything zeroed on my maft..that is supposed to be a sign of intake leak.

 

[Enigma_Man]

Your gauge should read exactly 0 when the car is off, because there's no vacuum or pressure in it. If it's off, then your readings will be off too Yours sound about normal, give or take the mis-calibration.

I gather that Autometer gauges are the "cheap" brand. They work well enough, but I've had two malfunction (one was sticking, another was about 5 psi off to begin with), just return them to whomever you bought it from, or talk to Autometer.

-Jesse