Wrong Cam Causes Engine Misfires
This bulletin applies to misfire diagnosis after installing a remanufactured engine in 2007-2011 Buick Allure, 2008-2018 Enclave and 2007-2016 LaCrosse vehicles.
The technician may experience a misfire immediately after installing a GM remanufactured HFV6 engine, usually limited to 1 bank or 1 cylinder. The condition may be caused by the wrong camshaft being installed in the engine at the reman facility.
If you experience this concern, inspect the camshafts to ensure the correct camshaft is installed in each intake and exhaust position by comparing the ring strategy to either the engine that was removed (best way) or by the chart available in the service manual.
Ring strategy camshaft identification is a series of rings along the camshaft that are either simply cast on the camshaft or machined down. There are five rings on each camshaft.