TROUBLE SHOOTING The ignition system is composed of a primary and a secondary circuit, The battery, ignition switch, primary coil winding, distributor points, condenser, and primary wiring are in the primary circuit. The secondary winding of the coil, rotor, distributor cap, high tension wiring and spark plugs compose the secondary circuit.
A. No Spark At Any SI)ark Plug Wire This indicates trouble in the primary circuit, in the rotor or in the high tension wire between the coil and the distributor. 1. Turn the ignition switch on, Hold the end of one spark plug wire %6 inch from the cylinder head while the engine is being cranked. Repeat this procedure in turn at each spark plug wire. If none of the spark plug wires produce a spark this symptom applies. If a spark jumps the gap from anyone or several wires, this symptom does not apply.
The fonowing procedure is designed to quickly locate the immediate cause of trouble, so that the engine can be started. A schematic drawing of the ignition circuit is shown in Figure 16. The numbers appearing in this drawing establish the location of units ~ the circuits.
EXAMPLE : In the following instructions and in the drawings, (7) refers to the coil terminal of the ignition switch to coil wire. 2. Check for good connections and firmly seated terminals, then continue as follows:
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Figure 16-Trado( Ignitiort System (1) If the engine starts, the trouble is in the primary circuit from the negative (hot) side of the starter relay (13) to the battery terminal of the ignition coil (1).
NOTE: Do not run lhe englne for more than five minutes with the wires (~onnected in this manner. Momentarily disconnect the ammeter lead from the battery (14) to stop the engine. If the ammeter now reads zero. crank the engine, a little at a time (with the starter), until a continuous reading is obtained (distributor points closed). Disconnect the ammeter leads from the battery and coil terminals. Disconnect the battery wire from the coil terminal (7). Tum on the ignition switch. Connect the ammeter positive lead to the coil terminal (7 ) . Working from the coil toward the battery, contact the ammeter negative lead consecutively to each of the primary circuit terminals (7) to (13) until an ammeter reading from 3 to 5 amperes is obtained. The faulty part of the circuit is between the terminal where a zero reading was obtained and the terminal where a 3 to 5 ampere reading is obtained.
a. Replace the coil to distributor high tension wire if the insulation is worn or damaged at any point where it passes near metal parts of the engine. Make sure the terminal (16) is soldered to the wire and is firmly seated into the coil terminal socket. Make sure the coil to distributor primary wire is making good contact at both ends. If trouble still exists, proceed as follows: b. Connect an ammeter between the battery negative terminal ( 14 ) and the battery terminal of the ignition coil (1). Tum off the ignition switch. Crank the engine with the starter, observe the ammeter reading while the engine is cranking, then follow the proper procedure.
Clean corroded terminals, tighten terminals, and repair or replace parts at fault.
(2) If the ammeter reads zero as the engine is cranked, the trouble is in the primary circuit from the battery terminal (7)
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