04/26/2025
This OBS Chevy rolled in after a fresh swap — a 5.3L out of an ‘05 Tahoe, motor was built by Jimmy Allard Auto Machine with flat top pistons, a mild cam, long tubes, and a cold air intake.
Here’s the cool part: a young 17-year-old did a lot of the work himself — installing the engine, wiring harness, headers, and cold air intake. Mad respect for getting hands-on and making it happen!
The issue? It was running extremely rich. The customer had installed 50lb injectors but didn’t have any data sheets for us to properly tune from — making it nearly impossible to dial in the setup the right way. Luckily, we had a set of factory AC Delco injectors on hand. We installed them at no charge just to help get him sorted.
During diagnostics, we also found the truck wouldn’t go into closed loop, and the O2 sensor data was all over the place. We recommended fresh O2 sensors along with the injector swap, and after installing both, the difference was night and day.
The truck finally went into closed loop, the rich condition cleared up, and we were able to start street tuning it the way it should be. Still a long process ahead of us but little by little we will get where we are trying to go.
Video credits go to the Client.