bziggy

Hello I have a question about the pf150 fuel system (otherwise known as air dog). I have it on my 2005 dodge ram truck, it's the pump and filter set up. The problem i am having is that when you turn the key to start the truck it takes 40 to 45 seconds to prime. The pump runs and the heating element goes out, but the pump still has not finished priming and stopped runing. I have everything installed correctly and have even gone over it to make sure. It's the same thing every time i go to start the truck like it loses the prime. If I start the truck before the pump stops piriming it starts and runs, but I'm still concerned. I want to know if anyone else has this problem or what you think i could do. Thank you!

cbrahs

is it staying running because of the return side of the system? also your signature says you have a 100 and the post is a 150?

bziggy

Sorry it is the pf 100 system . Is that mean it is saft to just start the truck and i do not have to wait for it to stop running / priming ? Also why would it do that , it will stop if you wait and then i have been starting the truck.

cbrahs

i think it would be safe. I did a security system install yesterday for a guy that has the 150 FASS on his twin turbo, twin CP3 truck and it stayed on as well. I have heard my factory lift pump stay on at times. most of the time i don't pay attention to it and just start it

jakeydiesel

so ur saying you just cant kick the key forward and start the truck? you have to let the pump run for 40 seconds or the truck will not start? if so, then yes youre losing your prime, possibly an air leak.

jakeydiesel

the pump is always running with the key forward, you just hear it before start up cause the motor isnt running...

bziggy

You can start the truck after the heating coil goes out without a problem. I hear the pump running and the fuel pressure gauge is up to about 20 psi for about 45 seconds and then it will stop running and the gauge goes to zero. This is when i have been starting the truck. For example if you shut the truck down and were to restart it right away the pump would prime for about 40 seconds and then shut down. You can see it on the fuel pressure gauge. I have been waiting to start the truck until the gauge goes to zero after you first turn the key. I figure this is when the system is charged and done priming.

Festus

If your wired so that the OEM wiring to you factory pump triggers the AirDog, then you're fine.

My truck does the same thing with the factory intank LP. If I don't actually start my truck after the grid heater light goes out, the ECM cuts power to LP after a few seconds - no need to keep the LP running if the engine isn't running...right? It only makes sense. Yes, one thing DC engineering did accomplish good on the fuel system. I can watch my guage drop as well when the power is cut to the LP and it turns off - there's a return line to the tank, so it won't hold the pressure.

bziggy

I believe I am not wired off the factory pump wiring. In the instructions it tells you to go off the fuse box and find a key on power only lead to power up the pump.

53 willys

dont listen to any of the old AD wiring directions.......you 05 should have the orange with red tracer wire cut and tapped as your airdog power/trigger.then it will run just like stock.......

53 willys

this is NOT true on the newer trucks......it primes for a few seconds and then shuts off...soon as you start cranking the starter over the pump will start to run again....

bziggy

Thank you could you tell me were this wire is or how i could find it please.

53 willys

on my 06 it is in the main wire loom that goes from the fuel tank to the fuse box....it was the ONLY orange/red tracer wire in there..I opened up the loom along the frame rail found the wire and cut/spliced it to the trigger on the AD harness....

53 willys

some wire pics in here....https://www.dieseltruckresource.com/...d.php?t=185809