We used to have to start car engines by key and listen for when the engine would “catch”. How does it know now automatically?

Question

This is probably already revealing how old some of us are, but we remember that we had to start our cars by turning the key and waiting to hear the engine “catch”. At that point you knew the engine was ok to proceed, and if you stopped turning the key it wouldn’t die.

How does the starter today (push button) know all this, and it never seems to get it wrong? I have never heard a push button starter fail to get it right unless some other issue like dead battery, etc. (and btw, today’s engines seem to have so far fewer issues like we used to have)

In: Engineering

Answer 1

the p01 computer in 99-03 chevy trucks looks for a crank/cam sync minimum run time vs crank speed.

i would assume they just added more stuff like airflow vs time or crank speed.

i reckon it’s probably all crank speed based since your average idle rpm is about 2-3x crank speed