Grounding : Fundamental

The basics of any electrical circuit is to have electric current complete a round trip from +VE to -VE of the power source; in this case, the car battery or the alternator +VE point and the -VE are usually grounded to the car body.

Sometimes, the connections are not conducting well especially when aged and contact points get corroded. Additional grounding cables are needed to help improve electrical performance in the car.

This article  will measure the resistance value of a NEW car and the results after grounding. Items needed :

– Grounding Cable Set (RM 50 above… depending on brand)
– Cable Tie

Time Spent :
– 40 Mins

Difficulty 
– Easy – Medium

First test of all, I attacked the Battery -VE Post to the ECU’s ground/body.


To my surprise, it doesn’t show me 0 Ohm… it is a 25 Ohm resistance value.

Next, was the Throttle body.. my guess is, since this is Drive by wire, Throttle body should have good electric flow to get best power..


Alas, the value was 844 Ohm . Which is kinda high.

Then, I attacked the next important ground point. The engine cover. As Spark plugs are grounded to the engine block itself.


5 Ohm, quite okie.. but can be improved.

Another very very important point is the Alternator.

I can see the original Grounding is from the alternator directly to the car body. Nice and thick wire. That explains the good flow at only 3 Ohm resistance…

Let’s check on the Original Grounding, from the Batter -VE terminal to the car body, nearest to the fuis box…


Hmm.. not too impressive. I thought it will show me a 1 Ohm. Alas, it is 2 Ohms.

Alright.. since I got the readings.. I am ready to ground the points.. I will be using these.. Pivot grounding cables.


Note, I made some modification to the cables as I do not need that long, so I bought Lugs and cut the wires shorter and put the lugs on.


Using metal polish such as Autosol, I brushed and cleaned the battery -VE terminal to ensure best connectivity… I later used Alcohol to wash the post and sprayed some WD40 on it to protect it from rust or corrosion.

OKie.. start to GROUND… TAKE NOTE of this… SERIOUSLY..
– This is the nearest to the Spark Plugs you can ground.. As the other nuts on the engine cover is to hold the engine cover down, and they are plastic, do not try to remove those.. THESE however, are nuts to hold the Fuel Rails and are connected to the Fuel Injector’s grounds…


Testing the resistance from the Engine Block to this nut.. @ 2 Ohm, this should help reduce the resistance of the original 5 Ohm to the -VE post.

Alright.. jobs done… Picture is taken with the Engine cover taken off. the 3 wires on the engine will be hidden from view.

Here are the points I grounded. (From left to right)
– Alternator. (As the power source to the car. This, is a very important point)
– Fuel Rail (The closest to Fuel Injectors and Spark PLug/Engine Block)
– Throttle Body (This was the highest resistance during the multimeter test)
– FireWall (All the in car electrical items are grounded to the firewall, make sense to ground here)
– ECU
– Fuse box… The original grounding is actually good enough.. I have extra wires left, so I grounded here.

After effect ?

The ECU shows me 1 Ohm !!!  SO does every other parts that was grounded…

What was the results after grounding?

– Less lag in throttle response
– Brighter headlamps
– Headlamps and dashboard lights do not dim when aircon kicks in
– Smoother acceleration and idling

This is one of the cheapest and easiers DIY for performance gain for the car. Do it!

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