I received an Air Dog Raptor 100 pump back in March. I had it installed and we thought my fuel pressure gauge was faulty. The fuel pressure would read 15 psi at idle but when I would drive the truck with moderate throttle, the fuel pressure would swing downward to 5 psi and not recover to 15 but swing past 15 and sometimes go to the 30 psi limit of the gauge.

I swapped out the gauge...two more gauges. Same problem. I was told it was the regulator and they sent me a new one. It was a Viton ball instead of the aluminum rod. Installed it...now the pressure would not go over the 15 psi limit but would still drop fast. I tried adjusting the psi...it would not adjust.

AD sent me another pump. Installed it. Preset to 15 psi. Worked good for the first couple of days. Then it started to lose fuel pressure...10 at idle. I replaced both fuel filters. No change. Swapped the gauge again...twice...no change. Called AD...they sent me another pump.

I was already leery about another pump and that feel good feeling was gone.
Got the new pump. Swapped it. Preset at 15 psi. Moderate throttle I see 2-3 psi drop. WOT throttle it drops to 5 and is slow to recover. I adjusted the psi to 20...at least this time I could adjust the psi. Took the truck for a run and I still see a big drop in psi under load...once I am at speed it levels off at 20 psi.

Its not like I have a huge HP truck. I am running a Smarty on SW 3 and everything at default.

For those of you that have an Airdog, have you encountered any of this?

I have logged a total of 420 miles since the first pump. My factory pump ran for over 155,000 miles holding 10 psi steady even under load...the most fluctuation I would see is the width of the needle. It started to fade out over the last 4500 miles and was showing signs of failure near the end.

AirDog has stood behind their product. However, this is getting to be a bit much with regards to all the time and effort to resolve, not to mention the uncertain feeling about driving the truck for any distance.

I have the factory filter and a 4 micron absolute high efficiency Baldwin filter after the pump.

 

Hey buddy.

Mine will play back and forth, but not more than a couple of PSI. Never had as drastic a change as you are seeing.

Wonder if there is something funny going on with your pickup tube?

 

That pump should have a ball and spring to regulate the pressure. Remove the apparatus and verify that the Viton ball is not stuck in the spring. That's what happened to my AD150 a few years back....pressure would fluctuate 5-10psi in both directions.

 

The first pump did not have the Viton ball...it had an aluminum shaft with a pair of springs. One spring course and one spring fine. Swapped out and pump eventually went erratic and was diagnosed with bad seals. The third pump, the one on the truck now is working good.

However, the Raptor does not come with a relay and you are expected to tie into the factory power wire to draw power for the Raptor. Over the past few days I have been told by a few folks that I had better get a relay on there to make sure that I am not pulling higher amps through the PCM but instead pull the juice from the battery...save the PCM.

Relay is going on first thing tomorrow a.m.

 

That's strange, my Raptor came with a relay kit. But it's a few years old now.

MikeyB

 

Thats what I recall as well. Having installed several I was certain it came with a replay yet when I asked...the answer was no.

Next up for me is to eliminate even the most remote possibility of the draw straw impairing my fuel supply. I will be going with a sump set up.

 

Have you put a vaccuum gauge on the suction side of the pump? The vaccum should less than 2inH2O.

What fuel module mods have you done?

Just as an FYI you might want to check the fuel module suction screen. Seen lots of fueling issues caused a plugged screen.

I've had seen a few issues with the fass and air dog systems, mostly due to pump/motor issues and injection pumps lossing prime, because these system seem to pull fuel out the injection pump causing them to have dry starts.

 

Sorry Scotty, just reread your post. I would run a relay system, I burnt out an ECM in my 02 running my fass. You also get more voltage surging from the grid heaters. I use cheap skate NAPA 40-50amp four/five plug relays. Run 12/14 gauge wire. I built my own fuel system using walbro 395 and a EFI fuel regulator.

 

did the relay yesterday, saw a PSI increase of 2.5 and less swing on the gauge.

Ordering sump next. Done with the draw straws. Tanks was cleaned out when we did the draw straw and then checked again as part of the trouble shooting with first pump. Now I have noticed that even with a viton o-ring on both sides of the draw straw fitting that goes through the top of the cansister, I get seepage when the tank is full. No more draw straws for me.

 

Seepage isn't good.. If fuel gets out, water/grit gets in eventually. The sump sounds interesting.

Looks like the pump was just taking too much juice from the system.

 

I'm just getting ready to installl my Airdog II. I hope I don't have the troubles you've had.
Is there a sealer that can be used along with the seals/washers that come with the install kit to stop any seepage ?

 

Funny you should say Scotty. My AD150 is currently giving me hassle. Intermittent working to now nothing. Truck still runs.