Electricity takes the route of least resistance back to the battery earth. If you have a poor earth connection, the current can pass back along other cables causing unusual problems to occur. I have managed to have the headlights come on with the brakes and even had the heater blower sucking air in. Poor earth connections will generally affect things that can run a reverse voltage like bulbs and motors.
As the quality of the earth connections deteriorate it can cause unusual temporary problems
plus you may notice a drop in performance, lesser MPG and an increased electrical noise through
the speakers. This can be made worse when an amp is installed, even though the amp is
earthed the standard earth cable cannot handle the extra load.
Upgrading the quality of the earth cables and the connections allows the electrons to flow
at their full potential. This makes the whole process more efficient and allows all the
connected devices to work more efficiently as well. Upgrading can:
Reduce electrical noise
Increase the efficiency of the spark plugs
Increase the efficiency of the engine
Increase the MPG
Give more power
Unleashing The Full Potential Of Your Spark Plugs
The spark plug is a very simple device, it introduces a gap in a high voltage system to create a spark between two electrodes. This spark ignites the compressed fuel/air mix to create the combustion in the engine. Each spark plug is fed by an HT lead from a coil pack. What many people don’t realise is there is no cable taking the electric away from the plug. The engine block actually becomes a part of the circuit, creating a route for the power to return to the battery.
If the engine earthing lead is degraded or poorly connected it can restrict the flow and therefore lessening the spark at the plugs. A lesser spark means lesser combustion when you need it. Lesser combustion means a lower performance and higher fuel usage per mile. Simply by upgrading the earth cable and increasing the connection you can unleash a greater potential from your plugs.
For years now, owners of Japanese cars have been upgrading their earth cables, quite often being the first mod they do. It releases extra power from the engine, increases torque and mpg.
People who are serious about car audio also upgrade the earth leads to negate the
electrical noise, the more surface area the cable has, the more power it can carry.
They also upgrade the battery earth and alternator earth. This increases the flow
to and from the battery allowing more power to reach the audio equipment.
A good power cable is essential but a good earth cable is even more important, without
it you get electrical noise over the speakers from the alternator and the coil packs.