Check for Leaky Injectors
This bulletin applies to 2015-2018 GMC Yukon vehicles equipped with a 5.3L or 6.2L engine, and 2019 Savana vehicles equipped with a 4.3L engine. Some customers may comment about an underhood fuel odor and/or starting the engine sometimes requires extended cranking time.
This may be caused by one or more of the fuel injector O-rings and/or seals being damaged or dislodged.
Verify that the fuel tank fuel pump module seal is not leaking. Inspect for leaking, damaged and deteriorated fuel lines, connectors and components from the fuel tank to the engine. Inspect the EVAP system for any damaged, loose or disconnected components and for a saturated EVAP canister. Inspect for evidence of fuel injector leakage on the cylinder head and nearby components.
Fuel injectors can leak fuel due to mis-positioned, split or torn O-rings and/or seals. Note: The fuel injectors MUST be rebuilt whenever the injectors have been removed from the fuel injector rail or cylinder head.
If equipped, replace the engine insulator if it has absorbed fuel or emits a fuel odor.