The fuel injector return line pressure regulator (14) maintains fuel pressure on the return side of the fuel injectors. The fuel that is not injected into the combustion chamber is used to help lubricate and cool the injector and is routed back to the fuel tank. The fuel injectors supply fuel directly to the combustion chambers of the engine. The high pressure fuel is supplied to the fuel injectors (1) through separate high pressure pipes. The fuel pressure sensor (4) provides a voltage signal to the ECM to indicated fuel rail pressures. The engine control module (ECM) controls the fuel pump pressures by using two fuel pressure regulators, fuel pressure regulator 1 is located on top of the fuel injection pump and fuel pressure regulator 2 (7) is located on a fuel rail (2). Fuel is drawn through the diesel fuel conditioning module (8), which combines a water separator, hand operated fuel prime pump, filter element and then through a fuel filter vacuum switch (9) to the fuel injection pump. A mechanical high pressure fuel injection pump (13), located below the engine intake, includes the fuel supply pump and the high-pressure pump. The fuel tank (5) stores the fuel supply. If the valve seat in the injector is leaking or the pressure regulating valve leaks then it will not build enough rail pressure to start the engine.
When energized, the piezo crystals expand, lifting the control valve off of its seat via a hydraulic coupler (connecting plunger below) to begin injection. The injectors have a piezo stack instead of an electro-magnetic solenoid. The fuel pressure regulator in the high pressure pump and the pressure regulating valve in the rail control rail pressure. The high pressure pump builds rail pressure and delivers it to the fuel rail manifold where it flows through the injector lines to the injectors. Piezo High Pressure Common Rail Basic Information If you don’t have service information you can buy a subscription online at or. Also note that 1 MPa (megapascal) is equal to approximately 145 PSI, 100 kpa is about 14.5 PSI.
In order to do proper diagnostics you will need a scan tool, diagnostic service information and some special tools such as a vacuum test gauge J44638 (OTC 6754) available from GM Special Tools or Freedom Racing Tool and Equipment. I have no reservations about deleting my emissions and tuning it and only wish I did it sooner.Chevrolet-GMC Diesel Diagnostics 2011-2016 6.6 L | 2007.5-2010 6.6 L | 2001-2007 6.6 L | 6.5 L DS Pump | 1982-1993 GM/Ford IDIĢ011-2016 6.6L LML – LGH Duramax PDF: 2011 – 2016 6.6L LML/LGH Duramax I do blow a little smoke when I get on it, but it's not rolling coal. My highway mileage went from 14mpg to 19mpg at 80 mph. I installed a 150hp emissions delete tune and woke that Duramax engine up. I also disconnected the electronic connections for the EGR valve. I also added a lift pump to make sure that that the increased fuel volume is maintained to keep from draining the fuel rails and taking a chance of damaging the CP4 high pressure fuel pump.
I decided to go for a delete tune by disconnecting my DEF pump, removing my DPF, but keeping my cat intact to keep it from droning and smelling like an old piece of mining equipment. I did run an EFI Live based emissions compliant tune, but it did nothing for my frequent regens or dismal mileage. I never had any DEF issues, but my refill warnings started to give me less and less mileage before it would go into limp mode. Yeah, you can tune it with the emissions intact, but you still have the DEF issues, regens, and crappy mileage.