Every great once in awhile if I stand on the truck pretty hard or just a heavy acceleration, I notice my FP drops at cruise from 16.5psi to about 14.5-15psi. It is the strangest thing because if I turn my truck off and restart it, the FP is back up to normal and doesn't give me any more problems for a couple weeks. Has anyone experienced this before or know what is causing it? Very strange...

I know that AD had a lot of issues with the built in pressure regulators on their pumps. Maybe this is an issue with the regulator? Whenever you stop the pump completely and start it again is might allow itself to reset itself so to speak internally.

I gotta ask the stupid question, try a different gauge? My ad2-165 has a totally different setup wonder if the airdogs are the same?

No I haven't because the it happens so randomly. Also my gauge is practically brand new and it's a mechanical ISSPro FP gauge. I am sure it is the pump and maybe there is something sticking in the line. Otherwise everyday at idle it sits at 18psi and on the highway I cruise about 16.5psi.

My Raptor 100 does the same thing on hard twists and turns in the road. It's weird.

Fuel pressure does bounce right back though without restarting

My Raptor 100 does the same thing on hard twists and turns in the road. It's weird.

Fuel pressure does bounce right back though without restarting

My raptor started doing this too. Not so much on corners but if I hit a big bump on the road it will drop for a second.

Intersting!  I thought I was the only one. It's like the bearing/ bushings are worn so it slows down for a split second. Mine will drop around 3-4 psi off the line too if I get on it.

Edited June 15, 201410 yr by JAG1

Ever since brand new mine has always dropped from 21 at idle to about 17 just cruising. If I do a WOT pull it will easily drop to 14 psi. That was brand new out of the box with brand new 3/8's fuel line from the top of the tank to the VP and new filters to boot. I have a fuel tank sump to install at some point and I am hoping that will cure my fuel pressure drops. It just recently started doing this drop-over-the-bumps thing about 5k miles ago.

Mine AD150 has about 6k miles on it. It just does it so rarely and only if I really get on it hard. Otherwise it is fine. Since restarting the truck always works, could it be an electrical issue?

My ad100 needs readjusting from time to time. Last adjustment stated for 8 months. I think in your case, the regulator is sticking open. Shutting it off resets the regulator valve seat. on restart pressure is back to normal.

My ad100 needs readjusting from time to time. Last adjustment stated for 8 months. I think in your case, the regulator is sticking open. Shutting it off resets the regulator valve seat. on restart pressure is back to normal.

 

Makes sense, what causes it to stick?

Poor design.....

 

Ed

Poor design.....

 

Ed

Figures... lol

 

On another note I have noticed the gauge making a faint but fairly noticeable buzzing noise which is not very rhythmic in nature. The needle itself has stated to "Shake" a teeny tiny bit but I don't know what is causing that. I do have the needle valve in place but I have yet to recheck it since install, I wonder if it has loosened up some?

Edited June 20, 201410 yr by Kotta390

Anyone?

I would pull the regulator out and inspect the regulator for wore parts and/or damaged springs. Don't forget the seats of the regulator...

I would pull the regulator out and inspect the regulator for wore parts and/or damaged springs. Don't forget the seats of the regulator...

 

Which part is the regulator? I did however tighten the needle valve till it closed and then I cracked it open a full turn and the noise went away so far. 

Needle valve on the fuel pressure gauge should be seated shut then cracked open barely so you have a 1-2 delay of the needle going from 0 to pressure.

 

As for the regulator in in the AirDog pull it completely out and inspect the plunger and/seats for damage.

Needle valve on the fuel pressure gauge should be seated shut then cracked open barely so you have a 1-2 delay of the needle going from 0 to pressure.

 

As for the regulator in in the AirDog pull it completely out and inspect the plunger and/seats for damage.

 

 

Oh ok gotcha. I was trying to figure out the buzzing noise.

 

Here is the video.

Edited June 25, 201410 yr by Kotta390

The buzzing I had quit after eliminating the isolator.

The buzzing I had quit after eliminating the isolator.

I don't have an isolator anymore.

Anyone recognize this buzzing? I have tried to adjust the needle valve and it doesn't seem to make any difference??