Chart C4A - IGN System Check With Integral Coil
NOTE:
The following step numbers refer to the numbers in the accompanying flow chart(s).
- 1) This tests for proper output from the ignition system. Using Tester (ST-125), check for spark at plugs. Tester requires a minimum of 25,000 volts to fire. This test can be used in case of an ignition miss because the system may provide enough voltage to run the engine, but not enough to fire the spark plug under load.
- 1A) If spark occurs with EST connector disconnected, pick-up coil output is too low for EST operation.
- 2) Normal reading during cranking is about 9-10 volts.
- 3) This tests for a shorted module or grounded circuit from the ignition coil to the module. The distributor module should be turned off so that normal voltage should be about 12 volts. If module is turned on, voltage would be low but above 1 volt. This could cause the 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 "Bat." terminal to "Tach." terminal.
- 4) This checks voltage output with pick-up coil triggering module. A spark indicates ignition system has enough output. An intermittent no start or poor performance can result if polarity of ignition coil and pick-up coil is not correct. The color of the pick-up coil connector has to be Yellow if 1 of the ignition coil leads is Yellow. If the ignition coil has a white lead, any pick-up coil connector color EXCEPT Yellow is okay.
- 5) This tests for an open module or module circuit. Applying 12 volts to module "P" terminal should turn module on and voltage should drop to about 7-9 volts.
- 6) This should turn off the module and cause a spark. If no spark occurs, fault is most likely in the ignition coil, not the module. A module tester could determine which is at fault.