Cruze

Fuel System Diagnosis

The fuel tank stores the fuel supply. Fuel flows to the fuel filter/heater element housing, which combines a water separator, fuel heater element, and a filter element. The fuel is then delivered to the high pressure pump. The mechanical fuel injection pump is located at the front of the engine. The mechanical fuel injection pump is engine-driven by the timing belt. From the high pressure pump, the pressurised fuel flows to the fuel rail. The fuel rail is equipped with a fuel rail pressure sensor and a fuel pressure limiter.

The fuel return system returns not used fuel to the fuel tank. Fuel is used to cool and lubricate the fuel injectors and fuel injection pump. If the high side fuel pressure becomes excessive, the fuel pressure regulator releases the fuel into the fuel return system. The return fuel travels through the fuel lines and then to the fuel tank.

A Cranks But Will Not Run or Hard Start symptom may exist if air is being drawn into the fuel injection system due to the following conditions:

Schematic Reference

Engine Controls Schematics

Electrical Information Reference

Scan Tool Reference

Control Module References

Note: 

Observe the scan tool Fuel Rail Pressure Sensor parameter. During engine cranking, the pressure should be at least 20 MPa (2 900 PSI). With the engine running at idle the pressure should be close to the Desired Fuel Rail Pressure parameter. As the engine speed is increased, the Desired Fuel Rail Pressure parameter and the Fuel Rail Pressure Sensor parameter should closely match each other.

Note: It may be necessary to remove engine components for the visual inspections.

1. Verify the following conditions do not exist:

•	Hoses and lines that are flattening when the engine is running, or have kinks that may restrict the flow of fuel

•	Fuel leaks between the fuel tank and the fuel injection pump

Note: A fuel return line that is leaking , is a good indication there is a restriction in the return system.

•	Fuel leaks in the fuel return lines

2. Repair any leaks, restrictions, or replace any components found to be damaged or leaking.
3. Engine running, observe the scan tool Fuel Rail Pressure Sensor parameter. The reading should be greater than 20 MPa (2 900 PSI)

⇒	If less than the specified range, remove the fuel tank and test, inspect, and repair the items listed below.

•	Leaking fuel lines

•	Restricted fuel feed pipe

•	Restricted or plugged strainer

•	Stuck or binding fuel level float

•	Inspect the harness connectors and the ground circuits of the fuel pump for poor connections.

4. If the fuel system components test normal, test or replace the fuel filter.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.