Gauge pressure transducer to Arduino

So I bought a Honeywell pressure gauge pressure transducer, with the following datasheet:
Datasheet

The thing is that I want to measure pressure in a small pressure tank, but first I tried to read some voltage out of the sensor and It printet 4.66V? The pressure sensor was not connected to anything, only the Arduino.
My code was:
int sensorValue = analogRead(A0);
float voltage = sensorValue * (5.0 / 1023.0);
Serial.println(voltage);
delay(1000);

I thought it would print out 0V when no pressure was applied to the sensor?

The pressure sensor has eight pins. How were they connected?

The post did not contain a complete program. When you are ready to post the complete program, here is how:

To post code and/or error messages:

  1. Use CTRL-T in the Arduino IDE to autoformat your complete code.
  2. Paste the complete autoformatted code between code tags (the </> button)
    so that we can easily see and deal with your code.
  3. Paste the complete error message between code tags (the </> button)
    so that we can easily see and deal with your messages.
  4. If you already posted without code tags, you may add the code tags by
    editing your post. Do not change your existing posts in any other way.
    You may make additional posts as needed.

Before posting again, you should read the three locked topics at the top of the Programming Questions forum, and any links to which these posts point.

If your project involves wiring, please provide a schematic and/or a wiring diagram and/or a clear photograph of the wiring.

Good Luck!

If you look at the transfer function graph in the datasheet you will see that the span is from 10% to 90% of supply voltage. So if you are using 5v, 0 would be .5v and full scale would be 4.5v.
This is a pretty common voltage span on a lot of pressure sensors.
I also noticed that some of these sensors are 3.3v and others 5v. Make sure which ones you have.
It looks like they only use pins 1,2 and 3.

1 v supply
2 v out
3 gnd