SEAL-O-RING 4502555 - Caterpillar

Set the engine control switch to the OFF/RESET position. Remove the electrical power from the engine.
Illustration 1 g01958654
Section view of the cylinders
(1) Cover
(2) Transformer
(3) 3-pin connector
Remove cover (1) for the suspect cylinder.
Pulling on the wiring harness may break the wires. Do not pull on the wiring harness.
Disconnect the ignition harness from 3-pin connector (2). Remove transformer (2) from the engine.
Illustration 2 g01958655
Ignition transformer and spark plug
(2) Transformer
(4) Extension
(5) Secondary terminal for the spark plug
(6) O-ring seal
Inspect the body of transformer (2) and extension (4) for corrosion and/or for damage. Inspect the spark plug (5) for corrosion and/or for damage.
Inspect the connection between the transformer (3) and the extension (4) in order to ensure that the connection is not loose.
Inspect internal O-ring seal (6) for damage.
The extension has an internal terminal for the spark plug. Inspect the terminal for looseness, for corrosion, and/or for damage. Insert a spark plug into the extension and check the terminal for spring pressure.
The extension can be scratched and damaged with a wire brush. Do not use a wire brush on the extension.
Clean any deposits from the inside of the extension. Use a 6V-7093 Brush with isopropyl alcohol. Expected Result:The transformer is in good condition.Results:
OK - The transformer is in good condition. Proceed to Test Step 3.
Not OK - The transformer is in poor condition.Repair: The inspection found a problem with the transformer. Repair the transformer, when possible. Replace the transformer, if necessary. Be sure to use the correct transformer for the G3500E Engine.Reset the control system. Restart the engine. Clear the logged codes.STOPTest Step 3. Test the Primary Circuit and the Secondary Circuit of the Transformer
Measure the primary circuit by checking the voltage of the blocking diode.
Illustration 3 g01959301
Schematic for the primary circuit and for the secondary circuit
(3) 3-pin connector for the transformer
(A) + Terminal
(B) - Terminal
(7) Mounting flange
(8) Blocking diode
(9) Flyback diode
(10) Primary coil of the transformer
(11) Secondary coil of the transformer
(12) Resistor
(13) Spark plug gap
(14) Internal terminal for the spark plug
Set a multimeter to the diode scale. Connect the multimeter leads to the terminal (A) and the terminal (B) of the transformer's connector. The polarity of the leads is not important. Measure the voltage between the terminals. Record the measurement.
Reverse the multimeter leads. Measure the voltage between the terminals again. Record the measurement.
Measure the resistance of the secondary circuit. Note: The resistance of the secondary coil will vary with the temperature. Illustration 4 demonstrates the relationship between the secondary coil's resistance and the temperature. A reading that is within 1,000 ohms is acceptable.
Illustration 4 g01447679
Resistance versus temperature for the Ignition Transformer Gp
Set the multimeter to the 40,000 Ohm scale. Measure the resistance between the mounting flange (7) and the extension's internal terminal (14) for the spark plug. Expected Result:For the primary circuit, one of the voltage measurements is approximately 0.450 VDC. The other voltage measurement indicates an open circuit.For the secondary circuit, the resistance between the screw for the ground spring and the secondary terminal for the spark plug is within the acceptable