The owner of a 2016 Chevy Silverado brought their vehicle in because he had been hearing a weird intermittent pinging or detonation (spark knock) noise after starting the engine. He could hear the noise through the exhaust and under the truck from inside the cab.
Case details
The technician connected a scan tool. There were no active diagnostic trouble codes (DTCs), the malfunction indicator light was off, and all the I/M readiness monitors had all run to completion.
The technician decided to run the engine with the truck up on the lift. While under the truck, it was easier for him to pinpoint where the noise was coming from – inside the bell housing.
He removed the starter to find that the Bendix on the starter was causing the intermittent metal pinging noise. While the engine was running, the Bendix would drift forward and touch the flex plate. When it hit the flex plate, it would ricochet back, slowly ease forward, and touch it again. The teeth on the flex plate were miraculously still in decent shape.
Confirmed repair
The technician replaced the starter, and the strange noise was gone. Problem solved!
