My car has an alarm system that has the ability to control a remote starter. To activate the starter it just sends a +12v signal through a wire.

I would like to design a circuit that will operate my starter, and send power to my ignition system.

I can already turn the starter over with a relay, and power the ECM and ignition system.

The problem I am having is how to get the starter to only turn over until the car is started.

Is there a wire or something that I could use to (de)activate a relay?


ANY help would be appreciated

 

Probably the simplest solution would be to find a vacuum switch that opens or closes contacts when engine vacuum reaches a certain point.

If the switch opens the contacts at say 8 inches of vacuum for example, the starter would crank, the engine would fire up and start to pull vacuum becuase it is now running under it's own power. The vacuum switch would now disconnect the starter. At just cranking speed before the engine catches manifold vacuum would not be very high, so the switch wouldn't cut out the starter.

You would need a safeguard timer to prevent the starter grinding on and on in the occasion that the engine doesn't fire right up.

A good source for a vacuum switch would be a mid 70s to mid 80s Japanese car. Just look for one with a million black boxes all connected to vacuum hoses. Believe me there were lots of these cars! You should be able to find such a beast if you look around.