I installed a airdog 100 and I finally install a glowshift fuel pressure gauge. I noticed the when I first ran the truck the gauge would read between 18 and 20 psi, then at times it would read between 16 and 20 lbs. Is the gauge the problem or the airdog...thanks :confused:

Hmmm... Good one... I would check your filters (cheap and easy) then check your suction line and pickup assembly... Since its a 100 series I could bet money the pickup screen in the tank could be plugging up (maybe).Kind of doubt the gauge is bad... Unless its a electric gauge WITHOUT a needle valve... Then the sender could be getting beat up by the VP44 pulses...

Another possibility is the injector pump flow return valve is stuck shut. With years of low fuel pressure not enough to trigger the valve to open, the valve can become stuck shut, not allowing excess fuel to return to the fuel tank. Mine did this initially after being installed and I called the Air Dog folks and they mentioned this possibility. My Air Dog would go up to about 24 psi at times but eventually with use stays stable at approx. 18 psi. I asked the tech. support guy about the pump putting out too much pressure and he told me they all get pressure tested before they leave the manufacturing facility. :confused: You may want to call and get some advice on the best course of action to take.

My Airdog has never ran that high. About 12.50 now with 2 years on it.When new it ran 15lbs. Everyone says shim it, but I am going to wait and see if it goes any lower.