06/17/2026
AMC Tech Tip - Testing, Trust, But Verify
Verify - Not only the equipment, but also the process. I’ve taught my team on any measurement to always first verify your readings. Then repeat.
Subject - This was a BMW motorcycle engine that had sat for six years in an unheated shed. And although it was running well, I was testing to establish a baseline for future service.
Test - The engine compression test is a time-honored technique for verifying the internal condition of an internal combustion engine. It’s often used to establish a baseline for diagnosing a low-power, misfire, or oil consumption concern.
Tool - First, verify your tool.
Know what you should expect before you begin your test. Then you can confirm your results with another gauge or verify them on another known-good engine. And use only good-quality, professional tools; much time is wasted with off-brands.
Process - Then, verify your Process.
In this case, the difference between a closed and open throttle during the testing process. Understanding how the system is supposed to work is instrumental in making a proper diagnosis.
Confirmation - Test again to confirm.
If test results significantly deviate from expectations or specifications, I always rerun the test at least a second time, if not a third, to confirm. If the results are inconsistent, I think of an additional way to run the same test.
Cheers,
Bruce