So exactly how it sounds. brand new 35 psi gauge and rather than reading 0 when the battery is on its reading 10 inHG (inches mercury) also tuned for 29 pounds and the gauge only shows 24 or 25 pounds at the peak. So diagnosis would be I have a vacuum leak right? That's what I would think so I re-did my vacuum lines twice and I'm still reading just as low. Any ideas? I would say its because I'm at 9100 ft, but it reads exactly the same down at 5280.

Maybe right where the vacuum line attachment screws into the pressure sensor, could that leak? I thought maybe so I put some plummer's seal tape on it?

Let me know what you think.

 

Gauges can be off, I have a prosport that I thought was at 29psi with Hallman MBC. Got a Omni 4 bar and logged it. It was showing peaks to 34-35...

 

First thing I would check is to see if you have to calibrate that gauge. If not then you have a defective gauge. There's no reason why you should see vacuum when the motor is not running. Call AEM and see what they can do for you

 

cool, thanks for the advice. I'm not so sure I can calibrate it, its the digital one, and I see no input to do so, I'll ask AEM. The "manual I got with it is pretty much useless. It just says hook to vacuum source and wire, or something along those lines.

 

I had a prosport evo boost gauge which was digital and it could not be calibrated to correct for elevation. Perhaps the AEM is the same way. Let us know what they say if you contact them.

 

I think you misunderstood why I asked about the calibration. I didn't ask for elevation. It's simply because the gauge should not show any vacuum with the car not running. I was asking if it can be recalibrated so the gauge would go back to 0 with the car off. Since the OP said he can't then the only option is call the manufacturer and get a new one