CDI (Capacitor Discharge Ignition) is an electronic ignition system that uses capacitive discharge to generate spark. A CDI box is an essential component of the CDI system. It is responsible for storing and releasing the energy needed to generate the spark that ignites the fuel in the engine. The 7 pin CDI box is a popular type of CDI box used in many small engines. In this article, we will discuss the wiring diagram for a 7 pin CDI box in detail.
What is a CDI Box?
A CDI box is an electronic device that stores and releases the energy required to produce a spark in the spark plug. It works on the principle of capacitive discharge, where energy is stored in a capacitor and then released in a high voltage pulse to generate the spark. The CDI system is used in many small engines, including motorcycles, ATVs, and snowmobiles.
How does a CDI Box work?
A CDI box works in the following way:
- The CDI box receives a signal from the ignition coil.
- The signal is then processed by the CDI box and stored in a capacitor.
- When the signal from the ignition coil stops, the CDI box releases the energy stored in the capacitor in a high voltage pulse.
- The high voltage pulse is sent to the spark plug, which generates the spark that ignites the fuel in the engine.
Wiring Diagram for a 7 Pin CDI Box
A wiring diagram shows the connections between different components in a circuit. A wiring diagram for a 7 pin CDI box is shown below:
| Pin Number | Connection |
|---|---|
| 1 | Ignition Coil – Positive |
| 2 | Ignition Coil – Negative |
| 3 | Ground |
| 4 | Ignition Trigger |
| 5 | Kill Switch |
| 6 | AC Magneto |
| 7 | AC Magneto |
Pin Number 1 – Ignition Coil Positive
Pin number 1 of the 7 pin CDI box connects to the positive terminal of the ignition coil. The ignition coil is responsible for generating the high voltage required to produce the spark in the spark plug. Connecting pin number 1 to the positive terminal of the ignition coil ensures that the CDI box receives the signal from the ignition coil.
Pin Number 2 – Ignition Coil Negative
Pin number 2 of the 7 pin CDI box connects to the negative terminal of the ignition coil. The negative terminal of the ignition coil is connected to ground, which completes the circuit and allows current to flow through the coil. Connecting pin number 2 to the negative terminal of the ignition coil ensures that the CDI box receives the signal from the ignition coil.
Pin Number 3 – Ground
Pin number 3 of the 7 pin CDI box connects to ground. Ground is the reference voltage for the CDI box and is required for proper functioning of the CDI system. Connecting pin number 3 to ground ensures that the CDI box has a reference voltage.
Pin Number 4 – Ignition Trigger
Pin number 4 of the 7 pin CDI box connects to the ignition trigger. The ignition trigger is a sensor that detects the position of the crankshaft and sends a signal to the CDI box to initiate the spark. Connecting pin number 4 to the ignition trigger ensures that the CDI box receives the ignition signal.
Pin Number 5 – Kill Switch
Pin number 5 of the 7 pin CDI box connects to the kill switch. The kill switch is used to shut off the engine in case of an emergency or to prevent theft. Connecting pin number 5 to the kill switch ensures that the CDI box can disable the ignition system when the kill switch is activated.
Pin Number 6 and 7 – AC Magneto
Pins number 6 and 7 of the 7 pin CDI box connect to the AC magneto. The AC magneto is responsible for generating the AC voltage required to charge the capacitor in the CDI box. Connecting pins number 6 and 7 to the AC magneto ensures that the CDI box receives the voltage required to charge the capacitor.
FAQ
What happens if the wiring of the CDI box is incorrect?
If the wiring of the CDI box is incorrect, the CDI system will not function properly. This can lead to a no-spark condition, which means that the engine will not start. It is important to follow the wiring diagram for the CDI box carefully to ensure proper functioning of the CDI system.
Can a bad CDI box cause a no-spark condition?
Yes, a bad CDI box can cause a no-spark condition. If the CDI box is not storing or releasing the energy required to generate the spark, the engine will not start. It is important to test the CDI box if a no-spark condition is present.
Can a CDI box be repaired?
Yes, a CDI box can be repaired in some cases. However, it is often more cost-effective to replace the CDI box rather than repair it. If you suspect that the CDI box is faulty, it is recommended to consult a professional mechanic for diagnosis and repair.
Can a CDI box be tested?
Yes, a CDI box can be tested using a multimeter or an oscilloscope. The testing procedure varies depending on the make and model of the CDI box. It is recommended to consult the manufacturer’s instructions for proper testing procedure.
What are the symptoms of a bad CDI box?
The symptoms of a bad CDI box include a no-spark condition, engine misfire, hard starting, and poor engine performance. If you experience any of these symptoms, it is important to have the CDI box tested and replaced if necessary.
