Application of Multimeters in Automobile Maintenance
Test ignition coil
Fluke analog/digital multimeter can test resistance from 0.01 Ω (Type 88) to 32M Ω. This makes testing the ignition coil very accurate and easy. A general multimeter cannot test resistance below 1 Ω.
Measure the internal resistance of the coil
If you suspect that the ignition coil is abnormal, you should check the resistance of the primary and secondary coils. The test should be conducted separately when the car is hot and cool, and each joint should be tested. The primary resistance of the coil is small while the secondary resistance is large. Specific indicators from the manufacturer should be consulted. The experience value is 0-several ohms for primary and 10K ohms or greater for secondary.
Test the connection of spark plugs
Check the spark plugs that have been used for many years and when there are signs that they may be a problem. Not all connecting wires have the production date of spark plugs. Due to high heat, the spark plug base and spark plug may adhere. So removing the spark plug may damage the delicate and brittle wires in the insulated wire. So when disassembling, it is necessary to rotate it repeatedly a few times first. If there is suspicion of a problem, the resistance should be tested while slowly twisting and rotating the wire. The resistance value is approximately 30k Ω per meter. The numerical value is related to the type of line. Some will be much smaller. To accurately measure * and compare it with the wiring of other spark plugs in the engine.
capacitance
Fluke analog/digital multimeter can also test the capacitance of a car, and the change in the analog helium pointer indicates that the multimeter is charging the capacitor. You can see that the resistance changes from 0 to infinity. Please confirm that the capacitance should be tested from both directions, and also check the capacitance under hot and cold conditions.
Test the leakage of capacitors
Use the resistance range of a multimeter to test the leakage of capacitors. When the capacitor is charged, the resistance should increase to infinity. And any other value indicates that the capacitor needs to be replaced. To test the capacitor, disconnect it from the car circuit for testing.
Hall Effect Position Sensor
The Hall effect sensor has replaced many ignition points on a distribution panel and is used to directly detect the position of the crankshaft and cam in non distribution panel ignition systems. It tells the computer when to ignite the coil. The Hall effect sensor generates a voltage that is proportional to the strength of the magnetic field passing through it. It can come from a magnet or an electric current.
Testing Hall Effect Sensors
First, check the voltage from the battery. Because Hall effect sensors require power supply while solenoid valves do not. When testing the sensor, first connect the+12V wire from the battery to the power terminal, and use a multimeter to measure the voltage output from the signal to the ground terminal. Insert the gap piece between the sensor and the electromagnet and observe whether the analog pointer of the multimeter changes. The value of the change should be between 0-12V.
Electromagnetic position sensor
An electromagnetic position sensor is composed of a coil wound around a magnet. Clear procedures for Pickup (contact) and Relictor (adjustment) are crucial. Its indicators are generally from 0.8mm to 1.8mm.
Test the pulse of electromagnetic distributor
Remove the distribution panel from the ignition module, set the multimeter to DC voltage, and connect it to the ignition head. When the engine is running, a pulse will appear on the analog pointer. If there is no pulse, it may be due to a malfunction in the adjusting resistance wheel or electromagnetic connector. The same method can also be used to test other electromagnetic position sensors.
