Some of us are probably familiar with vehicle circuits activated when we turn the engine ON - ie the ACC power circuit from the Key ignition, Glow plug power, starter relay...

Looking for a hint on where I can find a circuit or 12v signal that is activated momentarily when the engine is keyed off - ie for shut-down.

Looking for Puma model specific info, so the old EDIC motor is not an option that I can see. VCV in the puma fuel pump is fed 12V via fuse 15, switched via power relay R104, and a constant 12V supply before that. ECM controlled, so modulated by this 'black box' which according to the wiring diagrams, would possibly modulate VCV to earth somehow (PWM possibly?). This may not be as straight forward as I hoped just to pull a signal from...

As far as what happens during engine shut-down, I'm assuming there is some sort of fuel cut process (thinking the VCV), coupled with the throttle plate closing:

FSM is hazy on this exact mechanism of shutdown.

For a project idea I'm working on, I'm hoping to have access to a 12V signal when the car is keyed ON (this is simple), but also have a source of a 12V which is active only upon engine shut-down signal being given by key-off. This is to allow a circuit to default to closed circuit, but with the option of breaking that circuit by the operator. The kicker is that it will need to return to closed circuit after engine is shut down, without any operator input. An ON / Off pulse to a latching relay would do this nicely.

Wondering if such a shutdown signal exists, otherwise I'll get creative with relays to invert the ignition signal circuit.