Circuit/System Testing
WARNING: This page is about a different car, the 2008 GMC Sierra, 2008 GMC Cab & Chassis Sierra, 2008 Chevrolet Silverado, and 2008 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT:
You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
- Inspect for the following conditions:
- Fuel smell or leak-Refer to Fuel Leak Diagnosis .
- A plugged air filter collapsed air intake duct
- A restricted exhaust system-Refer to Symptoms - Engine Exhaust .
- Contaminants in fuel-Refer to Contaminants-in-Fuel Diagnosis .
- Install the CH-48027
to the fuel rail service port and crank the engine.
- If more than 5 inches Hg of vacuum was present during cranking, replace the fuel filter and inspect the fuel system restrictions.
- Perform the Engine Compression Test. Refer to Engine Compression Test
.
- If any fuel vapor was emitted during the engine compression test, replace the affected fuel injector.
IMPORTANT: During the replacement of the injectors, inspect the inlet and outlet fittings for corrosion or contamination. Refer to Contaminants-in-Fuel Diagnosis . - Crank the engine for 15 seconds.
- If the Actual Fuel Rail Pressure parameter is less than 10 MPa while cranking the engine, refer to Fuel System Diagnosis .