To measure the ignition coil resistance in external coils, place an ohmmeter at both terminals of the ignition coil to measure primary resistance, place it between the positive terminal and the coil wire tower and the coil on secondary resistance. Before verifying the primary resistance, disconnection of the distributor wire and electrical connector to the coil and 10-16 kilo ohms should be verified as primary resistance of most engines and 10.3-13.9 kilo ohms as secondary resistance of most 2.2L engines. In case the resistance is not within specifications, replace the ignition coil; otherwise, inspect voltage at the ignition coil wire harness connector. On integral coils where there has been provision of the distributor, check voltage at the positive terminal, measure primary resistance between terminals A and C (must be 0.58-0.86 ohms), and secondary resistance between terminal C and coil tower (must be 11.5-18.5 ohms). In case the resistance is not within specifications, change the distributor assembly. To install and remove external coils, disconnect the negative battery cable, strip out the distributor lead wire and electrical connector and then strip out the coil. In 1990-92 626 and MX6 models, normal aspirated and turbocharged engines are to be followed through particular steps with the wires to be tagged so that they can be installed properly. The ignition coil that is part of the distributor assembly cannot be changed individually; in case of failure then the distributor has to be changed.