Chart C-4C, Distributor Ignition (Di) System Check (Remote Coil): Notes
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- Two wires are checked to ensure that an open is not present in a spark plug wire.
- A spark indicates the problem must be distributor cap or rotor.
- Normally, there should be battery voltage at "C" and "+" terminals. Low voltage would indicate an open or a high resistance circuit from the distributor to coil or ignition switch. If "C" terminal voltage was low, but "+" terminal voltage is 10 volts or more, circuit from "C" terminal to ignition coil or ignition coil primary winding is open.
- Check for a shorted module or grounded circuit from ignition coil to module. The distributor module should be turned "OFF." Normal voltage should be about 12 volts. If module is turned "ON," voltage would be low, but above 1 volt. This could cause ignition coil to fail from excessive heat. With an open ignition coil primary winding, a small amount of voltage will leak through the module from the "BATT" to "tach" terminal.
- Applying voltage (1.35 to 1.50 volts) to module terminal "P" should turn module "ON" and "tach" terminal voltage should drop to about 7-9 volts. This test will determine whether module or coil is faulty, or if pick-up coil is not generating proper signal to turn module "ON." This test can be performed by using a DC battery with a rating of 1.5 volts such as AA, C or D cell. The battery must be a known good battery with a voltage of over 1.35 volts.
- This should turn "OFF" module and cause a spark. If no spark occurs, the fault is most likely in ignition coil because most module problems would have been found before this point in procedure. A module tester (J 24642) could determine which is at fault.