Injector pulse width under load tells you what fuel trim can.

Injector pulse width under load tells you what fuel trim can. Fuel trim look normal, no codes, but the engine stumbles under hard acceleration. Here's the pid most texts aren't watching and it shows you exactly what's happening. The injector pulse width is how long the injector stays open measured in milliseconds. At idle on a healthy engine, typically two to four milliseconds would be around normal. Under wide open throttle, that number climbs as a PCM commands more fuel to me the low demand. Here's how you want to use it. You would want to either use a scope or your scan tool in graphe in the injector pulse with alongside the map sensor and RPM during a wide open through auto acceleration. The pulse width should climb smoothly with RPM and load. If the pulse width max is out and the RPM keeps climbing, the injectors are 100% open on their duty cycle. If the injectors are wide open and they still can't keep up, you have a fuel delivery problem. Not an injector problem. If the pulse width drops suddenly during acceleration, the PCM is commanding the pull back of that actual fuel. Now I want to check for a knock sensor event or a fuel pressure spike triggering protection strategy by the PCM. The fuel trim show you the average, the pulse width under load shows you the moment and the moment where the fuel actually lives. I'll see you on the next one.