Air dog problems?

[little white yj 622]

i have the AD 150 with a straw. i have been running 17 psi all the time.all the way to empty. just lately i noticed that now it drops pressure when comming to a hard stop at 1/4 tank of fuel. like to 5 or less just for a sec the right back up to 17psi. I did just put a needle valve on the line to the gauge, and it's open a little. can this valve be causing my problem? and is it ok to drop pressure for a sec or two? i going to open the valve full open untill i get fuel tomarrow.

[Mopar1973Man]

Nothing new... Everytime I lauch hard from a dead stop at 3/8 or less I see the same thing... Needle valve isn't the cause... It might be the fact with the heat and slooshing of the fuel it might build a bit of pressure in the tank swelling the tank slightly. Then increasing the gap on the draw straw... Just a guess...

[little white yj 622]

Never thought of the heat thing. It's been hot here in Pa. and the AD was installed in OCT. last year.

[JOHNFAK]

Not sure - but you may be able to bump up the pressure at the low end and the hi end via the regulator spring. Page 25 (section9) of the link below http://www.injectorwarehouse.com/diesel/dodgecummins_diesel_airdog/install-manual-original-98-04.pdf See if bringing it up to 20 or so raises your low end when driving 1/4 full.

[jncornett]

My 05 did this at or below a 1/4 its the fuel moving to the front or rear of the tank... If you could hear your pump you could hear the change in pitch it makes as it loses and then gets a better supply of fluid at the draw straw after the momentum slows from stopping..

[JOHNFAK]

My 05 did this at or below a 1/4 its the fuel moving to the front or rear of the tank... If you could hear your pump you could hear the change in pitch it makes as it loses and then gets a better supply of fluid at the draw straw after the momentum slows from stopping..

doh thats a good point. I was thinking the draw straw is pretty much usually at bootom of tank. But yeah with enough space and fuel moving. Then the extra pressure (spring) will be no use.