Express 3500 V8-6.6L DSL Turbo VIN 2 (2006)
Fuel Injector: Description and Operation
FUEL INJECTORS AND RETURN LINES
A fuel injector is a solenoid device controlled by the ECM that meters pressurized fuel to a single engine cylinder. Fuel pressure is released from above
the fuel injector pintle, and is returned to the fuel tank through the fuel return lines. The difference in fuel pressure above and below the pintle causes the
pintle to open. Fuel from the fuel injector tip is sprayed directly into the combustion chamber on the compression stroke of the engine.
The control functions for the fuel injection system are integrated in the engine control module (ECM). During the manufacturing process, each injector's
flow rate is measured and recorded as injection quantity adjustment (IQA) flow rate data. The flow rate data is then etched as a hexadecimal number on
the body of the injector. This data, together with the injector's cylinder position, is stored in the memory of both the glow plug control module (GPCM)
and the ECM. When the ignition is turned ON, both the GPCM and the ECM monitor to ensure that the fuel injection flow rate numbers are present. If
any of the injector flow rate numbers are missing, the diagnostic for that control module will set the appropriate DTC.
FUEL INJECTION PUMP
