I drove my truck the other day and ran it fairly hard for the first time in months. The fuel pressure always carries around 17.5 pounds. On a hard pull it will come down to 14.5 to 15 pounds. I noticed that the guage hit 0 a couple times...its never done it. The Rail pressure fluctuated but did not hit 0What may be going on?

 

Your pressure gauge is after the filter and the lift pump, so I would suspect those two things first.

 

as in change the filters? I checked the two filters out and no dirt or residue-all clean fuel...Airdog is not new but I guess it could be trying to puke

 

Check your fuel pressure gauge and change your filters if you have not.

 

Were you low on fuel and hit the brakes to stop? If mine gets down to an 1/8 of a tank or so and I hit the brakes to make a quick stop the draw straw in the tank has no fuel to pick up and my pressure gauge will zero out and then come back up once it picks up fuel again.

Just a thought.

 

Mine does the same even with the factory fuel pickup basket.

 

hmm interesting thought. yes I was low on fuel. I guess the same thing could happen when kicking the truck down into third gear....fuel would run to the back of the tank.

 

I'm just assuming that since you have an AD150 you also have the draw straw. I made the mistake of having an almost empty tank and then dropping it to install my AD150 system. With the tank setting on the ground and then measuring to cut my straw was the wrong way to go. After installing the system (with an empty tank) I quickly realized I SCREWED UP!!!! With the tank re-installed.....the bottom sags thus leaving a good 1-2" of room for a "dry suction" so to speak in occurances such as a hard brake with low fuel.

I found this out very shortly after leaving my dads shop after the install. If I have less than an 1/8 of a tank I really have to use the brakes easy. On a hard brake, all the fuel runs to the front of the tank leaving the suction tube nothing to draw but air.....thus zeroing out your FP.....mine at least!

Hopefully that was your problem and nothing else.

 

actually I removed the bed when I installed and left the fuel tank mounted. I cut a 45 degree on the straw so I should be ok but I really think the problem was when the fuel maybe went to back of tank. I havent been able to drive the truck the last few days becasue of being so busy but I am goint to fill it up and see if the problem persists.

 

Thought Id do a follow up. This weekend filled the tank and didnt have one fuel presure issue. Guess it was an issue with not enough fuel in tank. Still concerns me though