2009 prostar isx crankshaft sensor issue

[Notch]

Until you replace the damaged tone ring you won't be able to troubleshoot this properly, even though the issue is **almost** guaranteed to stem from the crankshaft tone wheel at this point.

The reason being, the ECM references crankshaft position (aka where #1 piston top dead center is/was/going to be) based on a number of teeth on the tone ring as it passes the sensor. If you just have a bunch of teeth on the wheel then you will never know if the piston is up or down, just that it's moving. So to reference position of the crankshaft/piston, the engine makers leave a tooth off the wheel and the computer is able to count the teeth in between this "blank space". So if someone gives the tone wheel a new "blank" space then the ECM has no way to know if this space is supposed to be there or not, or if the piston is actually up, down, or where it is for calculation of engine speed, cylinder identification, etc.

Looking through my waveform library I found an old reference pattern screenshot from a CM871 BAC that I screenshot and saved for a know good reference. This is just a line pattern of voltage of a crankshaft position sensor output with an engine running at idle. There are 2 wider spaces in this waveform indicating the "missing tooth" space on the tone wheel. If you were to count the "mountain peaks" between the 2 wide spaces they would equal the number of teeth that are on a crankshaft tone wheel. If you were to knock another tooth off, the ECM wouldn't know any different and would think that the blank space was the factory reference missing tooth and not the one drilled off, throwing off all sorts of injection timing events.

Replace the tone wheel and report back.