Hello, in this opportunity I show you how to test a coil without drying without integrated power circuit. And I do it thanks to a rudimentary little tester.
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To test the DIS ignition coils (without distributor) you must have a little bit of expertise and rely as much as possible on the electrical diagrams of the vehicle to which the coil belongs.
Before explaining the connection mode, it will be explained in a general way how these modules work.
types of DIS cart coils
In the previous image you can see two basic diagrams of the DIS system, the upper part shows the system with power integrated to the coil and in the lower one the system with power in the computer.
Now, you may wonder how is this integrated power ... Well it is simple, for the coil to induce high voltage on the secondary, it needs two things. The first is that a large amount of current flows in the primary and secondly signal oscillation. Then to achieve the current of the current a transistor of high energy (not a platinum as it was done before) that is activated by the signal STE of the computer is used. Then depending on the manufacturer, they mount this power circuit on the coil or on the computer.
Having said the above, we can talk a little about how it works, and that is that at the appropriate time during the compression stroke in the cylinder, the PCM activates the signal called STE to the coil module that will activate the transistor inside the module, which in turn will cause electric current to circulate through the primary coil of the ignition coil, charging it. At the optimum time for the ignition to occur, the PCM will deactivate the STE signal and there, the transistor will cut the current flow through the primary winding (the cut mode of the flow also depends on the manufacturer). The magnetic field created collapses and induces a high instantaneous voltage in order to maintain the induced electric current, it will travel by means of the cable of the secondary coil and from there by the spark plug cable until it reaches the spark plug, which will burn the fuel and finally, it will touch earth.
So how do we identify the type of coil we have?
Well it's quite simple, with the help of a multimeter that measures resistance what we do is to test between two pins in search of which gives us resistance or continuity.
So as a general rule and as you can see in the first image when measuring a coil with integrated power, we will measure the semiconductor junction that will be infinite. When we do not have power integrated in the coil, we will measure the resistance of the low voltage winding.
How to know if our coil is in good condition or not?
For coils without integrated power
These coils it is possible to test the high winding and the low winding and have a clear idea if it is in good condition or not.
As you can see in the previous image, with our Chery A3 coil, the electrical diagram is below. So if we measure the terminals with a tester as indicated in the table, we have to:
1 y 3
0,8 ohms a 1,4 ohms
1 y 4
0,8 ohms a 1,4 ohms
A1 y A2
8 kohms y 12 k ohms
A3 y A4
8 kohms y 12 k ohms
If our measurements are within that range, we can ensure that our coil is in good condition.
As I mentioned at the beginning of the article, identifying the internal connections of the coil requires skill and knowledge of the mechanic.
For example, in our Chery coil we have terminals 1 and 2 are oneself. This would be evident in our multimeter as a resistance of zero or much lower than those of the other pins. Even measuring terminals 3 and 4 with the multimeter will give us twice as much resistance as 1 and 3 or 1 and 4. Because we have a serial connection of primary windings.
The same for high voltage coils, we must use the order of ignition, numbering of the coil or visually it is possible to identify them.
For coils with integrated power
It is only possible to test the high voltage winding and it is done in the same way as the previous one explained.
How is the coil functioning tested?
For coils with integrated power
Testing a DIS coil is simple, it is not even necessary to use any type of device to make the coil as in the old coils that needed the combination of a capacitor to increase the breakdown speed of the electromagnetic field, but rather the care is to know the function of the pins of the same to connect it correctly without damaging it.
It is recommended that before taking the tests, remove the coil from the vehicle, this is because if for some reason a spark jumps to a control cable that comes from the computer, it will irreparably damage it.
Now, the test procedure consists of the following:
In the previous figure, the circuit that must be mounted to test a 4 terminal coil typical of the Corsican chevrolet is shown. As you will see, it is simple with a tip connected to the negative terminal of the battery if you touch terminal S1 for 2 seconds and then move it away to jump the spark in core 1. The same will happen if you do it with point S2, except that in this case the spark will be seen in the core 2.
You must always connect spark plugs to the wires and they must be well grounded so that the current coming out of high voltage winding is properly discharged to ground. With this we guarantee that sparks do not jump between the internal windings of the coil which degrades quickly.
For coils without integrated power system
For these coils we must assemble a small rudimentary tester.
Materials we need:
A polyester condenser of 1 uF and 400 V
A 12V power source and at least 5A
A resistance of 38 ohms.
As you can see in the previous image, it is quite simple to put together. It only consists in connecting a low winding terminal to positive and assigning the negative terminal with a pushbutton or switch. Do not forget to place our polyester condenser in parallel. Beware, do not place an electrolytic capacitor on the circuit since it can not handle reverse voltage which causes it to overheat to such an extent that it explodes.
The resistance of 38 ohms is to terrify the other winding so that the current flows to our spark plug. If we do not connect it, the induced current can not circulate, which means that the spark does not jump or lower the intensity due to the losses.
How does our circuit work?
Well as I said at the beginning of the article, our coil needs current to circulate and oscillate so that the primary induces voltage to the secondary. We achieve this with the capacitor. Then when we close the switch the coil is charged with energy and when we open the suiche the current stored in the coil charges the capacitor then when the capacitor is charged it is discharged towards the coil in a swing of energy at high frequency (electrical resonance ). It is because of this phenomenon that we achieve the spark in our spark plug. If we remove the condenser, we will not make a spark.
Finally to finish testing our coil, we change everything to the second high coil as indicated in the following image:
Well it's all for the moment, and I hope you like it. Any questions or comments, leave it below in the question section.
Here is a video of how I did it:
If you like them, you can vote up at the beginning of opinions and give me 5 stars. jejejeje. Bye, bye
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