sounds like an alarm issue. Try disconnecting the battery, then reconnecting it. If it starts, and after shutting it off, it won't restart (unless you disconnect/reconnect battery) it is the alam. Something to try, mine did that.

 

My bet is on the knock sensor! Left side of block behind the exhaust down pipe, in particular, the wire from the sensor. Not necessary to replace, but definitely route wire away from heat. I repaired mine with plug wire insulating sleeves commonly sold in parts stores. ( NAPA p/n 7353956 ) I also recommend solder and heat shrink to repair wire as it does send signal to the computer. Russ

 

Sorry, correction!! I’ve got a Mini Cooper project hijacking my brain - it is the crank sensor not knock. Russ

 

I’ll try it. I thought if it was the alarm it wouldn’t be able to crank or start? Mine cranks but won’t start. Is this true? Maybe it can be either?

 

the OP changed the crank sensor with no change. Maybe the wires could be damaged?

the strangest thing is the delay the OP describes when you first put the key in. For 3-5 seconds it won’t let it try to crank. Then it will crank on demand and never fire