long start - fuel leak troubleshooting

[tha bobster]

2001 ram diesel 2500

I was having a long crank issue and last week when changing out my fuel filter i decided to fill my filter bowl with fuel and waited 20 min and it's definitely draining back to the tank. What is the best way to finish troubleshooting my leak?
Thanks in advance for your help
Bobster

[tha bobster]

Still looking for a little help here on this one.

[tha bobster]

HARD START, LONG CRANK TIMES, USUALLY WHEN COLD BUT SOMETIMES HOT, RUNS ROUGH FOR A FEW SECONDS AFTER START AND THEN CLEARS UP AND RUNS SMOOTHLY, OR, ENGINE SOUNDS DIFFERENT OR LOUDER UNDER LOAD, OR MAKES A CRACKLING SORT OF SOUND
AIR IN FUEL TEST
If the engine runs rough for a brief period of time after starting, just a few seconds, or sounds funny when running, this usually indicates air in the fuel supply system, caused by either fuel drain back or air getting into the fuel supply line somewhere. This symptom is NOT caused by the Injection Pump. Please know that good fuel pressure does NOT mean that there is no air in the supply line, as the pressure sensor doesn’t know the difference between fuel and or air pressure! My latest trick to accurately determine if air is a problem or not, is to get a 12 foot section of clear polyethylene or vinyl 3/8” hose from the hardware store and put it in the steel line between the Fuel Filter and the Injection Pump where the rubber section is. For aftermarket plumbing upgrades, figure out how to install it between the Fuel Filter and the Injection Pump. Loop it up under the windshield wiper for easy observation while driving and starting. Bleed the system to get all the air out of the newly installed line, and when you know the engine will be hard to start, monitor the line before, during, and after starting, and even driving, to determine if air ever gets into the pump. Be sure to drive the truck even if you don’t see air under no start or no load conditions, as air can be ingested intermittently from various sources only when the engine is under load. The hose under the wiper allows you to drive and diagnose the air situation under any and all circumstances you like, to see when it does or does not happen. This test positively tells you that you DO or DO NOT have an air issue which can be very important when diagnosing the VP44 fuel system. If you do have air in the clear line, run the engine from a can of diesel in the bed of the truck with a rubber hose stuck in it, connected to the inlet of the Lift Pump, and do the same test under the same conditions that saw air in the fuel, again. If the air goes away, the problem is behind the Lift Pump. If it is still there, the cause is forward of the inlet of the Lift Pump. This can be the Lift Pump itself, if it is a Fass with a leaky o-ring inside, leaking sealing washers, the water drain seal on the filter canister, or it can be leaking o-rings on the “Fuel Tubes” in the cylinder head. This last one is cool, as it shows its symptoms in a very unique way. If you park the truck facing up hill, overnight, on a fairly steep grade, it will start hard the next morning, but if you face it the other way on the same hill overnight, it will start fine! This is because of fuel drain back, and air getting into the system through leaky fuel tube o-rings and going to the highest place in the fuel system. When it faces up hill, the air goes into the fuel filter. When it faces down hill, it goes to the fuel tank! Call me if you need more help determining where the air is coming from.

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Thanks for nothing