Genuine Mazda 929 Ignition Coil

Mazda 929 Ignition Coil Parts and Q&A

• Ignition Coil
  JF01-18-100B
  Q: How to check ignition coil resistance on Mazda 929?

  A:

  To test the resistance of ignition coils to check on vehicles other than RX-7 in 1978-81, operate the engine to full working temperature, then detach the high tension lead to the coil tower. Measure primary resistance between negative and positive primary terminals on coil with ohmmeter, the readings should be 1.15-1.28 ohms (GLC) or 0.9-1.15 ohms (626). In case of secondary resistance, the ohmmeter is connected between the coil tower and the positive primary contact and 13,500 ohms of coil tower is expected in GLC or 7,000 ohms of 626. Replace the coil whenever either of the resistances is wrong by over 10%. To test 1982-89 vehicles, an ohmmeter is to be connected to the primary terminals; resistance is 1.0-1.3 ohms, with an exception of 0.72-0.88 ohms on 1988-89 626/MX-6 turbo and 929. Once the high tension wire is disconnected, measure the resistance between the positive coil terminal and the metallic connector in the coil tower with an expected reading of 10,000-30,000 ohms, with ranges of some models dependent. Test bad coil insulation under 10 000 ohms or bad by measuring resistance between the negative primary connection on a coil and body metal, less than 10,000 ohms indicates bad coil insulation. In case the coil passes testing, check the cap and rotor and check the resistance of the wire, which should be 16,000 ohms/meter. In RX-7 cars with 1979-85 models, coils are to be at regular operating temperature and then the leading ignition should be checked, 1.22-1.48 ohms is expected, and the trailing coil should be checked. In 1986-89 RX-7, on both ends of the wiring differentiate between leading and trailing coils and examine both terminal sets with resistance exceeding 1 ohm. External resistor of 1979 RX-7 must indicate 1.26-1.54 ohms each side. To remove and install, the negative battery cable needs to be disconnected, the protective boot must be removed and the high tension wire must be pulled off the coil with care. Clean-up the primary terminals (where needed), and install the new coil with all connections clean and tight. On RX-7 models with 1979-85 label and disconnect wires prior to coil removal, and with 1986-89 models label and disconnect wires with the built-in igniter on each coil.