Yellow wire is your ignition wire.
purple is the trigger wire for the starter. Yellow is the ignition wire.
The ignition wire that run to the cap is red. The one that to the key ignition is blue.
The ignition wire on a 1997 Ford E-150 is red. It is the same color in many of Ford's automobiles.
The ignition wire in a Nissan 350z is black and red. The starter wire is white/red and the second starter wire is white/green.
The ignition wire for the 2001 Ford Ranger is yellow. This is the 12 volt constant wire. Other wires in the harness are red and blue.