Heat shields are a good idea. The real issue is the battery..or the push to start switch. You need a switch that is good for lots of Amps. The solenoid is greedy.A weak battery will gause the same. The key switch type has a big contact for the solenoid. Ford and Jeep solved the problem with a starter relay. They work well and take the current away from the push button, if the button is something you want to keep.
