If You have a motorcycle, scooter, lawnmower, or outboard motor. You may face a starting problem. This problem is just because of faulty or bad CDI. Now, you might think about how CDI affects the system. All the automotive ignition systems are based on CDI boxes. So, to run the ignition system efficiently CDI must be in good condition.
So, Let’s start! In this article, I will explain in detail the CDI and how to test The CDI box with a multimeter
What Is CDI?
CDI stands for capacitor discharge ignition and is the brain of the ignition system. This is a black box which is full cover with all the electric circuits. This black box is located underneath the seat of a motorcycle.
After the 1980s all automobiles come with this CDI box. The reason for this CDI box is the efficient ignition system.
This article helps you to understand all you need to know about CDI box and its testing process with step to step and easy guide.
How CDI Works
CDI consists of three main components named the stator, in which the engine charging system generates a low voltage electric signal sent to the trigger coil.
The other component is the trigger Coil, which receives the signals from the stator and then sends them to the Control unit.
The three and most important component is the Control Unit (CDI Box). This CDI box uses the signal to charge a capacitor received from the trigger coil. After changing the capacitor the CDI creates a high-voltage spark to discharge the stored energy. In the engine’s cylinders, this high-voltage spark ignites the fuel.
CDI box charges the capacitor for facilitating the ignition and helps to continuous engine runtime till the time of charge.
what are the signs of bad CDI?
How to test The CDI box with a multimeter? A Bad Capacitor Discharge Ignition (CDI) unit shows the following signs or symptoms which in turn lead to testing and make the importance of the process of how to test the CDI box with a multimeter.
- Engine Misfires:
Bad performance and reduced performance of the engine are the results of the irregular firing of the spark plug. This is one of the signs of Bad CDI.
- Engine Stalling:
The engine may be stalled or lead to low speed or idle showing the sign of faulty CDI.
- No Spark:
The engine may not be able to start or run because faulty or Bad CDI does not help or produce the Spark to work at all.
- Backfiring:
Backfiring is one of the signs among all other signs of faulty CDI. Due to backfiring unburned fuel ignites in the exhaust system.
- Poor Fuel Economy
Due to the Bad CDI, the engine is not working well or performing as optimal and leading to poor fuel economy.
Other symptoms may also include a faulty spark plug or ignition coil.
how to test the CDI box with a multimeter:
Once you have completely understood what the CDI is? and the basic components and functions of CDI, the next step is to test if you have a sign of bad CDI. To test the faulty CDI we need a multimeter, Outboard engine, Spark plug tester, and Spark plug wire to test perfectly.
As you know the multimeter is a handheld device that measures consistency, voltage, and resistance. So, to test the measure resistance set the multimeter to the Ohms settings.
Now move to the testing process of how to test The CDI box with a multimeter
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Locate the CDI box and Remove
The Hot Test Of CDI Box
The Cold Test of CDI Box
Before wasting any time now I will explain in detail how to test The CDI box with a multimeter
Step 1: Locate the CDI box And Remove
The first step of how to test the CDI box with a multimeter is to locate the CDI box in the motorcycle. This box is black and located near the engine underneath the seat of the motorbike. This box is connected with multi wires.
Once you locate the CDI box in the motorbike the next thing is to remove the CDI box from the motorbike. Whenever you are going to perform any ignition work to prevent electrical shock or damage to your equipment it’s very important to remove the battery or power off the battery and don’t touch this until this get’s cool or releases the stored energy.
Step 2: The Hot Test Of CDI Box
After you set the multimeter and want to hot test by using the multimeter you don’t need to remove the CDI box from the stator. This is a fast and quick method than the cold test where you need to remove the stator. In this method test is conducted via the stator end rather than the CDI end. Blue and white wire comes from the stator to the CDI box.
Tip: This method is fast but difficult to lead connection via a connected CDI box.
To perform a hot test you need to keep in mind the resistance of the blue and white wires and set the blue wire to the white wire or white wire to the ground.
Reading between 77 and 85 needs to be measured for blue to white wire and reading between 360 to 490 ohms need to be measured for white to ground wire.
If your multimeter shows the resistance according to the above-mentioned reading it means your CDI is working well. But if both these differ so this means your CDI is faulty or needs replacement.
Step 3: The Cold Test of CDI Box
This is the continuity test for the CDI box. To conduct this test, set the multimeter to the continuity between the ground wire and other terminal points. In this test, if you hear any beefing sound from the CDI box this means CDI is faulty or something went wrong with the CDI box.
When you are conducting this test problem includes the SCR, Diode, or internal capacitor.
If you can conduct this test in the right way you may rectify your CDI box.
Safety Tips:
Before conducting any testing you must have the required material to save from any danger or any electric shock. You must have eye protection glasses, waterproof gloves, and cut resistance.
Final Words:
How to test a CDI box with a multimeter? If you have any problem with your capacitor discharge ignition system, without any delay test the CDI box by the above-mentioned steps which are very easy. After testing you will be able to fix the problems causing engine misfires or stalling.
Read Also: How to test cdi box with multimeter
FAQs
How do I know if my CDI is not working?
If you have engine misfires, engine stalling, and poor fuel economy so you may understand that CDI is not working properly.
What causes a CDI box to fail?
There are many reasons like wiring short, faulty charging system, and most important CDI box failing CDI may be old.
What is the main function of CDI?
CDI control discharge ignition is the main component in any motorbike. This control the ignition system to work properly.
How do I know if I need a new CDI box?
If you have signs like a dead cylinder, engine misfires, engine stalling, or engine not starting easily so you need to replace or either a new CDI box.