SPOOLITUP

Hey guys, this may be dumb but I gotta ask. I have an Airdog 2/165. The spring you just pulled out of yours there.... Does mine have one? I'm assuming it's on yur return line to the tank?? Does mine not have it cause it's adjustable pressure? I've battled fuel pressure issues forever even having the pump swapped, changing relief valves on the 44 3 times, redoing all fittings, changing gauges and finally I just gave up for awhile and have been living with pressures all over. Nothing under 10 though. I just recently got the 0216 code , yes I know, but it's been going on since I bought the dang truck. Any helps appreciated. Oh, it's sumped so no straw issues. Thanks....