airdog motor running but not pumping fuel

capt dong · Jul 4, 2014

changed filters. truck died after a couple seconds. primed a million times. no start. checked the schrader, no air even. ran pump with fuel bowl cover off, no fuel flow. pulled airdog filter no fuel flow. motor is running but isnt pulling diesel. i have a 1/4 tank of fuel. is this why folks go with a sump? how do i get it running? is the motor shot though its running? need your help. thanks. btw did an intrawebs search but only could find random stuff.

HD F250 · Jul 4, 2014

Did u pull the filter or separator also? I you have algae in your tank it will clog a 2 micron filter. Ask me how I know.....:frustrate:

From their website:
Priming Issues

Pump Won't Prime: Loosen the fuel filter (not water separator) while the PureFlow® product only is running. This will allow the air to be released. The tone of the motor will change as fuel enters the gerotor.

Immediately after hearing the tone change. Tighten the filter back up.

Still Not Priming: Remove water separator. Turn the PureFlow® product on. Place your thumb under the water separator nipple. Ensure there is suction at the water separator nipple.

capt dong · Jul 4, 2014

loosened filter with no change.

thumb over nipple with no change.

TD-5 · Jul 4, 2014

Did you change both the filters on the AD?. I know they don't recommend it, but pre filling the filter elements with clean diesel before installing them almost eliminates the possibility of an air lock. Is it possible the primary filter seal didn't seat properly. If it absolutely won't prime you can pop the cover off the pump rotor & see what it looks like.

capt dong · Jul 4, 2014

yes changed both filters. also filled both with diesel. the big filter was tough to seal since the lip was rubbing on the bracket but i got it locked down. if i remove the motor cover would it possibly reveal any kind of damage?

TD-5 · Jul 4, 2014

The seal on the primary water sep filter is the one that would suck air as its on the suction side of the pump. There isn't much behind that end cover but the pump rotor & a couple o ring seals. You would be able to see if the pump rotor is badly worn. If you pull the motor assembly from the base there are some seals between them, but I can't remember exactly what.
Maybe try disconnecting the suction line to the tank & stick a hose on the pump suction into a container of clean diesel. if it pumps fuel then it would indicate a problem with your suction line /tube in the fuel tank. Seems odd that it was ok before changing the filters.

capt dong · Jul 4, 2014

since there wasnt any suction on the nipple where the W/F separator spins on im inclined to believe theres something wrong with the AD.

i bought this for better filtration and reliability. this is defeating the purpose at a great expense. i just bought a bunch of replacement filters. its only been on the truck for 10k miles. i guess i call pureflow and see what they say or is there anything else i can do???

HD F250 · Jul 4, 2014

I know it sucks, but pureflow took care of me and sent me a new motor ASAP. Good luck!

capt dong · Jul 5, 2014

just in case it was fuel level added ten gallons to the tank that put me 2/3 of a tank and nothing. pulled the inlet hose and there was fuel there. removed cover off of gerotor and it was clean and no signs of leaks. today the motor was waning and cutting in and out. if pureflow sends me a new motor i guess itll be at least a week before i get it. does anyone know if they send stuff for warranty overnight?

AirFishAutomotive · Jul 6, 2014

what filters because it shouldn't rub the bracket

capt dong · Jul 6, 2014

donaldson and baldwin. the lip rubs the part of the bracket the bolt holes come through. that part not a big deal since i can just grind it down a hair.