How do you test a primary ignition coil?
How is it measured?
- Set the multimeter to measure resistance (ohms).
- Connect the positive lead to the positive terminal of the coil.
- Connect the negative lead to the negative terminal.
- A typical value would read 0.4 – 2 ohms.
How do you diagnose a coil?
Some of the most common tell tale signs that a coil may be defective include:
- A rough idle.
- An unexplainably louder-than-usual engine.
- A noticeable lack of power.
- A significant drop in RPMs while accelerating for no apparent reason.
- A blinking or intermittently activating check engine light.
How do I test a coil wire with a multimeter?
Use the digital multimeter, set to Ohms Ω. Simply attach or hold a meter probe on each end of the cable and read the total resistance on the meter. The Society of Automotive Engineers suggests the maximum resistance should be 12,000 ohms-per-foot. However, some OEMs have recommended different maximum resistances.
How to test primary and secondary ignition coil circuits?
The reading should be between one and four ohms, depending on the type of coil and the vehicle from which it came. The higher energy the coil, the lower the primary resistance will be. Test the secondary circuit by attaching one lead to the negative terminal of the coil, and the other to the terminal where the spark-plug wire plugs in.
How do you test a 12 volt ignition coil?
Turn on the multimeter and set it to the “ohms” function. Insert one of the multimeter’s probes into the center opening of the coil, contacting the metal terminal inside the coil. Touch the second probe of the meter to the ignition coil’s grounding terminal. The meter should read 6,000 to 15,000 ohms.
What should secondary coil resistance be on 12 volt car?
The normal, acceptable range for a standard 12-volt car is 1.5 to 1.7 Ohms. See if the reading is within this range. Set the meter to 20K Ohm setting, and attach the leads to the ignition coil’s center terminal. The reading for secondary-coil resistance should be 11, because if it is lower, that’s the reason why sparks are not appearing.
What should the resistance of an ignition coil be?
Most ignition coils should have a primary resistance falling somewhere between 0.4 and 2 ohms; however, refer to your manufacturer’s specifications for the correct reading. If a reading of zero is displayed, that signifies that the ignition coil has shorted internally in the primary windings and needs to be replaced.