When I bought my SPI guage it used to rest at around 2 bars under 0. While I was wiring up the light I had to go into the guage & re soldier the pos. wire...anyways you can calibrate the needles resting point yourself once you are inside the guage. Just drill out the pins that hold the back on, pull the back off & the innards will slide right out. Push down on the copper dial thingy to move the needle down & vise versa to go up. Hope this helps. That is how the SPI's come apart anyways, but I'm sure they are all pretty much the same.
