Vehicle remote ignition - Some questions.

Ah, i've already got the remote ignition up and running over wifi, it works fine?
But the way it's set up is in the arduino program it simply has a delay for the ignition relay to be on for, which is 1200ms
but like i said, for cold mornings, sometimes 1200ms isn't long enough.
i need some way of the arduino sensing that the car is running, and thus switching off the ignition relay

It's an old hilux with no immobilisation or anything so it's a piece of piss to get the starting side of it done.