MSefi.com read only forum (Jan.15,2018)

Thats where the microcontroller is a thing of beauty.You could do something through hardware, but 1 pic the size of your 555 could be 70 to 80% of the parts needed.

Thats got to be easy if you wanted to make a seperate module.
You just need to program a pic or the like to do this.
1. Upon power on,turn cel on then off.Then time while monitering rpm in and if there is none in the given time, then turn on the CEL.
2. If the rpm stops and power still on then turn ...