How come my '06 stickshift Subaru with dead battery refused to start with ignition on, rolling downhill, unlike my old cars? When the battery was charged it worked.
Your old cars probably didn’t have electronic fuel injection, or at least the type of fuel injection we have now. With no electricity to power the injectors…
If the battery is completely dead, it won’t work on a newer vehicle. If the battery is low, but you still get dash lights when you turn the key on, it will work. Your ECM, fuel pump, ignition system, etc. needs some power to get the car started.
Your battery needs to have enough power in it to “excite” the alternator fields. Then the alternator can supply what the low battery cannot.