Fault Code: 1145

[JimT]

Seems I had a little more rolling around the back of my head over night...

Cummins says that 2 fuel filters are REQUIRED for these engines. The pressure side, engine mounted, 5 micron primary filter and an OEM supplied suction side secondary filter/water separator rated at 10 micron. Visually, your's looks just like the Davco unit on my Pete. Same location and slightly peeling black paint.

Also, the fuel system on these engines, that are equipped with a priming pump, is designed to bleed off air. Thats why the cummins docs say that pre-filling the fuel filter is not required (although the fleet guard filters say to pre-fill and have a removable plug to prevent pre-filling the wrong side...). So, if you're getting some air introduced from the Davco (suction side) the system should compensate.

If you get a lot of air then the primary filter could run dry and stall the engine. Also, you'd likely get code 559 for low fuel rail pressure. I know this first hand from my own Davco sucking air due to missing o-ring experience mentioned above.

My opinion: replace the Davco unit. It's likely distorted from years of mechanics over tightening the plastic. AND look for a cause of your massive fuel rail pressure leak. If you performed an injector/rail leak test as Rawze suggests (build pressure, key off then on and data monitor for psi loss) and lose that much pressure while the engine is off then the Davco is NOT the source. It's something in the high pressure rail circuit. Could be the injector, could be a check valve, could be something else. Follow the troubleshooting in quickserve. Also parts.cummins.com has nice schematics of the fuel system and listings of all the different components to help you find where they are.