Car will only caught fire mainly due to wiring issue. Of course there is still some others cause like fuel vapour and static sparks but mostly main culprit was from electrical wiring.
Some like i mentioned before, too many tapping connection in single wired, loose connection (hence create spark) or wire deteriot.
Most common fault i see was lose connection and overload. For example, installer A will use this cable for speedmeter. Thn installer B will use the same cable for turbo timer thn installer C will use the same cable for something else. Here you already overdrawn the power from what the wire design to hold for. Hence as time goes by, the insulation of the cable will melted due to heat and once the naked cable core touch any metal will create sparks. Several small mini sparks will then create fires.
As for loose connection, the same example apply. Only that installer B and C doesnt know the same cable was used by Vendor A, and he pull the cable to reach result the previous connection came out or loose. They normally twist both cable together thn tap with cable tape which is not strong enough and installer B and C doesnt know that. Its normal for installer to use the cable which its eaiser to find or use.
each cable can only hold this much of ampere current draw if you're not aware. Try to use batt jumper cable which is small thn jump start a bigger batt, hold it long enough and you can feel the cable how hot it will become. Some even cant be touch at all. Hence you see normally those batt shop jumper cable is diff from those petrol kiosk selling. Those are welding cable and the core was very fine type hence result better current flow and heat resist.
This is the very same reason why grounding will improve car performance in certain manner. As stock grounding is only sufficient to cater for stock application, adding more items will only strained them even more. Providing extra grounding and shorter path will improve electronic sensor signal more accurate/fast and reduce interference
hence result improvement in several area. With signal manage to reach ecu more accurately and faster, ecu will able to react faster hence more responsive engine. If you have those gadgets, the reading will be more accurate as less interference.
Side track, Calvin, this is why i emphasis and spent so much on those grounding cables that i gave it to you.
