duster75

O.k I installed air dog 100 about 700 miles ago and yesterday it left me and my 7 month old daughter stranded. No 3/4" wrench to bleed injectors(witch is what it took to get it running) its got 3/4 tank of fuel and keeps losing its prime. drove it home let it idle in driveway for 10 minutes shut it down.Tried to start it 3 hours later, pump runs for 30 sec's(longer then normal) at 16psi shuts off try to start and nothing again. Have to crack injectors to get it started. *** is going on here no signs of leaks/ places air could be getting in I'm at a lose going to call them to see what they suggest. Nate

duster75

Talked to the boys at pure flow and its either the pressure reg on vp or the check valve ball and spring on return side of air dog. they say that vp is reg 7-10 psi ar dog 16psi could make vp reg. stick open..... how do you fix that?"

tesla440

I would ask them if you could get the adjustable regulator that they use on with the AD II. That would make it adjustable to the pressure range. Otherwise you will need to find out what springs that they use & change them out at the AD unit.

duster75

tesla440, (like them both BTW) I think the problem is that the ball and spring are stuck open in either the vp or ad not holding pressure when truck is shut down so it sucks air and I have to bleed to get it started.... what I'm wondering is at the V>P> what do you do? Do they make a heavier spring for it to handle the higher pressure? Nate

bent valves

The spill back valve in the VP is designed to leak air. There is both a spring loaded check valve along with a small bleed hole. It is made this way so the VP can rid itself of air. It is unlikely this valve is causing your problem as it is not used to control lift pump pressure.

I wonder if the people at Pure Flow confused it with a 12 valve pump. Here the spill back valve will block all flow if the engine is not turning and the valve is responsible for controlling the lift pump pressure.

My guess is that there is an air leak somewhere between your tank an VP, or possibly from the spill back valve on the VP back to the tank. Check those connections one more time.

duster75

bent thanks for info. I tried /cleaned all bypas valves and nothing.Still have to bleed to get started.Cannot find anywhere it can be suck'in air but it is. Box is off and going to install drawstraw tomorrow thing that blows my mind is that 2 tanks of fuel have been run since install and all the sudden this.Guess I'll find weak link but it sure has me P>off. I did talk to Toby at pur flow and he says its a air problem thought it was at sender. I'll put drawstraw in and we'll see from there. Glad I'm laid off and got all this xtra time on my hands. Nate