The fuel pressure gauge should be mounted in the cab with the line and connections tight and the tube pulled under the hood.

1. Choose a mounting location for the isolator such as the lip of the battery box or weld seam on the fire wall or fender and make sure the tube from the gauge is long enough to reach.

2. Hold the isolator in your hand with the red caps removed and the gauge side up. Use the eraser of a pencil to gently push the diaphragm down.

3. Fill the gauge side of the isolator as full as you can with glycol ( 50% water & 50% antifreeze ) and install the fittings.

4. Connect the tube from the gauge to the isolator you just filled and tighten the fittings to secure the tube.

5. Install the Banjo-bolt into the fuel system at the fuel filter head at the front port or inlet to VP-44 (i.e. Schrader valve) and connect the tubing to the isolator.

6. Hold the isolator vertically with the large screw on the fuel side up, turn the ignition key to the on position and crack the screw until a little fuel comes out and retighten the screw.

7. Mount the isolator and the job is done.

On 1998.5-2002 Dodge trucks idling normal fuel pressure is 12-15psi and you don't ever want to see the fuel pressure below 5psi. That is the pressure at which damage can start to occur to the VP-44 pump. On 2003-2004 Dodge trucks normal fuel pressure is about 8psi and can drop down to 4psi without causing any problems.