HUMMER TIP OF THE DAY
Posted: Thu Feb 18, 2010 8:51 am
Some customers may complain of a SES light and a constant engine misfire. In some cases, they may also complain of an engine tick/knock noise. During diagnosis, you will find no compression on the misfiring cylinder(s) with 100% leakage into the crankcase.
This may be the result of an aftermarket ECM calibrations/components and detonation that lead to a melted piston.
•If a lighted bore scope is available, inspect the top of the related piston(s) through the spark plug hole to determine if any of the pistons are melted. If this type of piston damage is noted, it is most likely the result of aftermarket ECM calibrations and/or components. If this type of piston damage is present and aftermarket items are found engine repair will definitely be needed.
•Inspect for aftermarket components, such as an exhaust, ignition, high performance air filter (K and N style), or air intake system.
•Determine if factory ECM calibration numbers are present to determine source of calibration.
This may be the result of an aftermarket ECM calibrations/components and detonation that lead to a melted piston.
•If a lighted bore scope is available, inspect the top of the related piston(s) through the spark plug hole to determine if any of the pistons are melted. If this type of piston damage is noted, it is most likely the result of aftermarket ECM calibrations and/or components. If this type of piston damage is present and aftermarket items are found engine repair will definitely be needed.
•Inspect for aftermarket components, such as an exhaust, ignition, high performance air filter (K and N style), or air intake system.
•Determine if factory ECM calibration numbers are present to determine source of calibration.