Last month set pressure went from 19psi to 16psi. I tweaked the adjust screw back to 19psi. Today it is at 22psi idle. 19psi no load. Been readjusting for the last year. up down, up down. Is this normal? Thinking I will just watch it for a while.

When the weather is colder, my FP is lower until the fuel has been recirculated and it thins out. Any other time it stays the same. Where are you taking your reading from? Before or after the fuel filter?

my raptor had to be adjusted once or twice a year. towards the end it wouldnt hold pressure well and no adjusting would fix it.

My Raptor will be lower when the intake heater is on, and lower when it is cooler, but will slowly come around to where it was set at 20 lbs when everything warms up. But it is only 4 lbs low when cold, so I don’t worry about it.

Glad I have pulled the trigger on a AD lift pump- seems to be some concerns with them.

I have this problem too from time to time. It's been steady for over half a year now. Not sure what the cause is:shrug:

Direct reading industrial oil filled 0-30 guage plumbed to the injection pump inlet fitting.

When AirDog produced the external adjustable regulator this problem came with that system. There has been spring replacements and issues with that system since the beginning. The old school spring and check ball works very well it a bit messy but you get solid pressure with out a bunch of up and down changes.

My ADII has an adjustable regulator and I have not touched since I installed. Got it set to 19 and it is still there. Installed it 2.5 years ago. The regulator might be different on the II vs the other pumps, I dont know.

Being externally adjustable, What is the difference between adding a shim washer or turning in the adj. screw 1/8 turn

I would think they both accomplish the same thing.

Being externally adjustable, What is the difference between adding a shim washer or turning in the adj. screw 1/8 turn

I would think they both accomplish the same thing.

but there is something about the external adjustment that has issues. I've haven't had a chance to see one and see the differences in the design. Like I know the old school spring and check ball had a issue about cramming the ball back in the spring but I figured out a solution. Just egg shape the last coil and the problem is solved for a home user. As for a future design fix was to make a shouldered washer that keep the diameter of the spring constant like old holley accelerator pump springs. But AirDog never listen to my idea even when I talked to the tech department.

Direct reading industrial oil filled 0-30 guage plumbed to the injection pump inlet fitting.

This is not suggested. Water hammer pulses will eventually damage the gauge... I know it liquid filled but water hammer pulses are the strongest at the Bosch VP44 injection pump since its the source of the water hammer. It always suggest and best to hook up the pressure gauge as far back from the Bosch VP44 injection pump and forward of the last fuel filter.

I don't know about the ADII but on the AD Raptor the external regulator is nothing more than a hollow screw the more you turn it in the more fuel is allowed through it which increases pressure. May be different with the ADII because they have a fuel return where the Raptor doesn't

I dont know what is inside of mine. I set it 2.5 years ago and it has held since. I figure if I mess with it now I'll start having issues. But if we get to the point of needing to know the difference I'll open her up.

Last month set pressure went from 19psi to 16psi. I tweaked the adjust screw back to 19psi. Today it is at 22psi idle. 19psi no load. Been readjusting for the last year. up down, up down. Is this normal? Thinking I will just watch it for a while.

I had my first 100 die several months ago after 3-4 years on the truck. Sent it back to Missouri and they sent me a new one. Installed it and adjusted it for 18-21 pounds pressure. Then 3-4 months later for no reason I can figure out it dropped and started running 10-12 or lower at WOT. Adjusted it one more time back up to the above pressure and its stayed there just fine. Hope nothing changes!

I had my first 100 die several months ago after 3-4 years on the truck. Sent it back to Missouri and they sent me a new one. Installed it and adjusted it for 18-21 pounds pressure. Then 3-4 months later for no reason I can figure out it dropped and started running 10-12 or lower at WOT. Adjusted it one more time back up to the above pressure and its stayed there just fine. Hope nothing changes!

Well I guess I commented too soon. The pump puked on a drive to the mountains yesterday. We started out holding 20 psi or so and after 30 miles or so it started dropping, the same thing that happened to my Raptor 100 15 months ago. Kept an eye on it and after a while it was all the way down to 11-12 psi and I knew I was losing a pump again. This is the 3rd replacement (one leaked, two died) pump from Pure Flow. Luckily I figured out how to limp the puppy home. You stop every 20 miles for 2-3 minutes and let the pump cool down and that gives you a good 15 psi for 20 miles. Limped the truck home and its now sitting outside... sent the email to Pure Flow today that its time for the 4th pump. Problem is that the truck is now not reliable and I cannot have that so not sure what the next step is but its very clear that we cannot depend on the Raptor 100 pump's anymore... FT