Re:Reset "Drive by Wire" cho Lacetti CDX 1.6
Đây là một bài ở diễn đàn khác nè các bác, thử đọc tham khảo thêm về grounding kit :
What is grounding?
Before going into grounding, one must understand that when a circuit is running, it is actually electrons running from negative terminal to positive terminal of power source (Battery or Alternator).
You have many electrical appliance inside your car: Fuel pump, Air cond, Light, ICE, Spark plug, etc...
Every one of them have negative and positive terminal as well just like a light bulb you have in your form 5 lab.
Their positive terminal is connected through a bus of positive wires which is linked to battery and alternator's positive terminal.
However the negative terminal of those appliances are connected to car's body with some wires connecting back from car's body to battery's negative terminal (This is oftenly mentioned as GROUNDING).
What if poor grounding?
Your stock car has complete grounding system but it may not be GOOD. Poor grounding means there are RESISTANCE between, if there are resistance, electrons that are trying to pass your electrical appliance will be slowed down or blocked and thus lower the amount of current supplying to those appliances. So what? those appliance doesn't get full current and of course not operating in optimum state.
In old car, the body metal is degraded and not so electrical conductible and thus resistance is even high.
How to know if your car has poor grounding?
All you need is a VoltMeter to measure the electron flow. Normally when you touch the red measuring point of Voltmeter to positive terminal of battery and same for black/negative point, you will get a voltage reading because electrons flow from negative terminal of the batttery through the circuit of voltmeter and then flow out to battery's positive terminal.
For example, we measure how good is alternator's grounding:
First, start your car, then touch voltmeter's red stick to negative terminal of battery and black stick to outter metal of the alternator. If the original grounding is not good, then electron will tend to follow your voltmeter stick to battery's negative terminal and you will see a certain voltage reading.
Well now don't move the voltmeter sticks, use a thick grounding cable to touch the alternator's outter metal and battery's negative terminal and you will notice the voltage dropped, this is because those electrons rather flow through the grounding cable instead because it's better in conductivity. If no voltage drop after you apply the grounding cable, it means that your existing grounding system is good. However don't be so happy about this, you are measuring this while your car is not moving/reving, if you move your car, electron flowing rate is higher (Because alternator is spinning faster) and your existing grounding may not be enough anymore. Not last, you're only measuring the grounding between alternator and battery's negative terminal, there are many points still.
What's next? Car body & Battery negative terminal:
Do the same as above, but the black stick of voltmeter touch on firewall of car body. Same concept as above applied.
Why normally VS come with grounding cable?
After knowing the functionality of grounding cable, you know it serves as basis for optimum circuit performance. If you add a VS into your car, during voltage drop (due to air cond kick, or unstabil voltage pattern by alternator) the VS will try to compensate the drop by supplying electron out so that your appliance feel less of the voltage drop. If you have poor grounding, electrons supplied by the VS cannot reach those appliance fast enough and thus it is not performing at it's full potential.
Which point for your grounding needs?
You have to measure using above mentioned method to determine which is the weak grounding point and apply grounding cable on it. However i believe many people doesn't have this patient or tool to do it, you can refer to following standard points for grounding:
1. Left Body <-> Engine Head
2. Right Body <-> Engine head
3. Firewall <-> Engine head
4. Engine Head <-> Battery Negative Terminal
5. Battery Negative Terminal <-> Body
Safety dos and don't
1. Do not let the grounding cable touching the engine's super hot metal part, you can round the cable through somewhere which is not so hot
2. Do not let the grounding cable hanging somewhere nearby radiator fan, in case the cable goes into the fan haha you know what will happen ?
3. Do not let the grounding cable hanging nearby running aircond belt.
4. Harness your grounding cable tightly.
How to choose good grounding cable?
In the market, there are many brands including HKS imitation, some colorful type, or those very common RED color power cable are having some "problem". Let's look at the step for checking the quality of cable:
1. Look carefully into the cable's insulator thickness, many cables claimed to be 4Gauge however the performance is even worse than 8Gauge or 16 Gauge, you know why ? it's because the insulator is thick and make you feel like the cable is thick but indeed the actual conductor inside is so small or thin.
2. If you can cut the cable, cut it and see how big the diameter of the conductor wires inside, if the conductor wire inside is thick then the grounding cable can conduct more current and it's good. But this may not be true, check out the step 3 before deciding.
3. Copper purity, 80% of cables in the market come with copper + aluminum, some real cheap one even could consist of 10% copper + 90% aluminum where this kind of cable is really useless for grounding cable because the main conductor material is copper not the aluminum, adding aluminum is just to save cost and fill the cable to make it thick.
So if you see those packaged 5 grounding cable offering at price below Rm 50 then you know it is suspicious and could be using one of above methods to fool their customers.
Ok finished with the look of the cable and what if you don't really know how to check with the 3 steps above, now go to something more rigid where we can measure the useful of grounding cable by using DC clamp meter. Install the grounding cable to your car and measure using the clamp meter, if the cable is carrying at 0.5-1 ampere, then either the cable is very poor quality or you're connecting to wrong point
(I have a meter, you can request for a test measure if we COD
)
The cable that i'm selling here could carry up to 25 amperes so far i have observed in Saga BLM. However current will be distributed if multiple grounding cables is installed in a car, so around 7-15 amperes could be observed and you will know these cable is useful when installed to your car.
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http://forum.lowyat.net/topic/1495749
