SERVICE TIPS

ECM - When in doubt. . . Clear it out!

The ECM used on our engines since the 2006 model year have many more capabilities than earlier ECM’s had. They have the ability to control the throttle, ignition timing, fuel trim and many other things as well as the ability to learn and remember those adjustments so it can control the engine operation the same way the next time the engine is operated under those same conditions. This function of the ECM is referred to as “adaptive learning”.

Besides remembering when the engine is running well, the adaptive learning also remembers what is going on when the engine is running under less than ideal conditions. For example, if the engine has a fuel pump that is putting out slightly less pressure than it should be, the ECM compensates for the lower fuel pressure and increases the fuel injector on-time and other parameters to reduce the possibility of engine damage. The adaptive learning remembers this and on subsequent start-ups, uses this stored information as a starting point. If you discover the issue and correct it, the ECM doesn’t know that and adjusts the engine parameters based old information. The ECM will eventually  ”un-learn” the old information and “re-learn” how to run the engine with the appropriate fuel pressure, but it takes some time for this process.

​You can speed up this process by hooking up Diacom going to the “Tests” tab. There are two items on the tests tab that you need to look for. One is called “Clear Fuel Adaptation” and the other is “Clear Misfire Data”

​​All you have to click on each one independently and follow the instructions. This will set everything back to a starting point and let the fuel adaptation and misfire counter start learning from a clean starting point. When in doubt … Clear it out!