Circuit/System Description
Ignition voltage is supplied to the malfunction indicator lamp (MIL). The engine control module (ECM) turns the MIL ON by grounding the MIL control circuit.
The Engine Cranks but Does Not Run diagnostic table is an organized approach to identifying a condition that causes an engine not to start. The Engine Cranks but Does Not Run diagnostic table directs the service technician to the appropriate system diagnosis.
The Engine Cranks But Does Not Run diagnostic table assumes the following
- The batteries are completely charged. Refer to «Battery Inspection/Test (Non-HP2)»(ref-238228-S06464573042006072400000) or «Battery Inspection/Test (HP2)»(ref-238228-S39090846112006072400000) .
- The cranking speed is within specifications. Refer to «Engine Cranks Slowly»(ref-238228-S20970594432006072400000) .
- There is adequate fuel in the fuel tanks.
Fuel is drawn by the fuel injection pump through a pre-filter screen in the tank and to the engine through the fuel supply lines. Fuel flows to the fuel filter/heater element housing, which combines a water separator, a hand prime pump, fuel heater element and a filter element. The fuel is then delivered to the high-pressure pump. The integrated hand pump is used to prime the fuel system after changing the fuel filter or servicing the fuel system. The mechanical fuel injection pump at the front of the engine valley includes the fuel supply pump and the high-pressure pump.
Fuel is used to cool and lubricate the fuel injectors and the fuel injection pump. The fuel return system is designed to return this fuel to the fuel tank. If the high side fuel pressure becomes excessive, the fuel rail pressure relief valve releases the fuel into the fuel return system. The return fuel travels through the fuel cooler to the fuel tank.
The fuel injector balance test is performed when a misfire, knock, excessive smoke, or rough running condition exists with no electrical DTCs. This test uses the Balance Rate and Cylinder Power Balance test to identify cylinders that are not producing the designed power output. The balance rate adjustments are utilized by the engine control module (ECM) only at idle. The balance rates are the fuel adjustments for each individual cylinder based on the variations in engine crankshaft speed. The balance rates will change depending on if the transmission is in Neutral or Drive. During the Cylinder Power Balance portion of the test, the ECM turns OFF individual injectors while the engine is running. The ECM adjusts for the drop in engine RPM during cancellation and may not change on the scan tool display. The lack of power at the cancelled cylinder will feel like a misfiring cylinder or vibration. If a fuel injector is turned OFF and there is a no difference felt when compared to the other cylinders, that cylinder is identified with the concern. If the customer concern occurs during idle or during off-idle tip in acceleration, the balance rates are used to identify the cylinder with a fault related to the fuel injector or engine compression.
The fuel injector balance test is performed when a misfire, knock, excessive smoke, or rough running condition exists with no electrical DTCs. This test uses the Balance Rate and Cylinder Power Balance test to identify cylinders that are not producing the designed power output. The balance rate adjustments are utilized by the engine control module (ECM) only at idle. The balance rates are the fuel adjustments for each individual cylinder based on the variations in engine crankshaft speed. The balance rates will change depending on if the transmission is in Neutral or Drive. During the Cylinder Power Balance portion of the test, the ECM turns OFF individual injectors while the engine is running. The ECM adjusts for the drop in engine RPM during cancellation and may not change on the scan tool display. The lack of power at the cancelled cylinder will feel like a misfiring cylinder or vibration. If a fuel injector is turned OFF and there is a no difference felt when compared to the other cylinders, that cylinder is identified with the concern. If the customer concern occurs during idle or during off-idle tip in acceleration, the balance rates are used to identify the cylinder with a fault related to the fuel injector or engine compression.
The purpose of the inspection maintenance (I/M) complete system set procedure is to satisfy the enabled criteria necessary to execute all of the I/M system monitors. When all system monitors are completed, the I/M system status indicators are set to YES. Perform this procedure when more than one of the I/M system status indicators are set to NO.
The purpose of the inspection/maintenance (I/M) complete system set procedure is to satisfy the enabled criteria necessary to execute all of the I/M system monitors. When all system monitors are completed, the I/M system status indicators are set to YES. Perform this procedure when more than one of the I/M system status indicators are set to NO.
The fuel filter/heater element housing consists of a water separator, a hand prime pump, fuel heater element and a filter element. Fuel passes through the fuel heater, which is operated by a built-in thermostatic switch. The thermostatic switch opens or closes to turn the heater ON or OFF, depending on temperature. Fuel then passes through the filter and the water coalescer, where the droplets of water in the fuel combine into larger drops that fall into the water reservoir in the filter. When fuel flows to the fuel injection pump, the fuel is clean and free of water.
The fuel filter/heater element housing consists of a water separator, a hand prime pump, fuel heater element and a filter element. Fuel passes through the fuel heater, which is operated by a built-in thermostatic switch. The thermostatic switch opens or closes to turn the heater ON or OFF, depending on temperature. Fuel then passes through the filter and the water coalescer, where the droplets of water in the fuel combine into larger drops that fall into the water reservoir in the filter. When fuel flows to the fuel injection pump, the fuel is clean and free of water.