I have the Autometer "Z series" Pyrometer in my truck. It never reads "zero", never has.
With the key off, my pyro' indicates somewhere between 100° and 200°. After sitting over night (engine stone-cold), key on: it will read somwhere between 0 and 100. Also, mine does not go through the "calibration" routine either, not all gauges do that.
After a short drive, then sitting ideling, mine reads 300°-350°F, depending on outside conditions. That's pretty normal. There was a Banks pyro' in my truck before, and it indicated the same.
I wouldn't worry to much about it reading zero, as long as it is reading fairly accurately at the higher-end temperatures. What does it read when you on the hi-way, cruising along at, say, 60-65mph? You should be seeing temp's of ~500°-750°F then. What's your temp do under hard acceleration? You should see ~900°-1100°F, maybe higher if your running performance mod's.
The fact is, type-K thermocouples (that's the "sensor" in the exhaust) like to operate at higher temperatures; that's where they are most accurate. The same goes for your pyrometer gauge. It's simply not designed to be super-accurate between 0 and 100-150°F.
Again, don't worry to much about it's accuracy at '"zero"...just as long as it's reading correctly at 1000°!
One last thing: Where is your thermocouple (sensor) mounted, pre-turbo or post-turbo?
From Autometer's website:
The pointer will move backward to the stop pin and then display actual temperature. This procedure is an auto-calibration function and is performed on every power-up. While this test is being performed, the gauge may make a clicking sound. This is normal.
NOTE: When the ignition is off the pointer may not always rest at zero.
Not ALL Autometer gauges will go through the "auto calibration" function.
Your fuse panel will be different so I don't know which one you would use but I do know that the power to the gauge(s) HAS to be "on" when the key is in the run and start position. If you hooked the power up to a spot that only has power in the run position and not the start position, then thats more than likely your problem..
That shouldn't matter. As long as you have power to the meter in "run" position, you're fine. Many dash-gauges are not powered in the "start" position.