As I mentioned. Kung luma ang kotse ay advisable maglagay ng Grounding Wire. Dahil puro loose connection na mga Terminals causing Voltage drop. Voltage drop robbed voltages for Headlamp, Ignition Coils and charging of Alternator to Battery. Therefore affect performance.

Worse if your starting your car with poor ground connection and in Cold Start.. Starter consumed high ampere to drive the Clutch Solenoid and DC Motor of Starter. The voltage drop on loose connection will decrease torque of Starter and Ignition Coil Voltage will drop to 8V. Induced high tension voltage much needed for Cold start engine will therefore reduced to 18KV instead of 25KV. This was the reason old cars have a hard starting problem.

Google about Ohms Law and it will help understand voltage drop.