3406E and 3456 Generator Set Engines Caterpillar

The ether injection system will improve cold weather starting of the engine. The Electronic Control Module (ECM) controls the ether injection system. The ether injection system has two operating modes. The ether injection system can operate in automatic mode and in manual mode. The engine oil temperature and the engine speed (rpm) are used to determine ether injection. The ether injection system is disabled if there is an active engine shutdown.

In the automatic mode, the ether injection system is enabled when all of the following conditions occur:

• Engine oil temperature is less than 0 °C (32 °F).

• Engine speed (rpm) is between 35 rpm and 500 rpm.

In the automatic mode, the ECM energizes the relay for the ether in cycles of six seconds. The ether is turned ON for three seconds. The ether is then turned OFF for three seconds.

Manual mode is activated by pressing the starting aid switch. In the manual mode, the ether injection system is enabled when all of the following conditions are met:

• The starting aid switch is placed in the MANUAL position.

• Engine oil temperature is less than 10 °C (50 °F).

• Engine speed (rpm) is between 35 rpm and 1200 rpm.

In the manual mode, the ECM energizes the relay for the ether for one cycle of six seconds. The ether is turned ON for three seconds. The ether is then turned OFF for three seconds.

In manual mode, ether injection is disabled if engine speed (rpm) is greater than 1200 rpm. In manual mode, ether injection is also disabled if coolant temperature is greater than 10 °C (50 °F).

Illustration 1	g01075681
Schematic for the ether injection system

Test Step 1. INSPECT ELECTRICAL CONNECTORS AND WIRING

1. Verify that there are no circuit breakers that have been tripped.

2. Turn the circuit breaker for the battery to the OFF position.

3. Turn the Engine Control Switch (ECS) to the OFF/RESET position.

4. Thoroughly inspect J1/P1,ECM connectors and J3/P3 Machine interface connector. Inspect all other connectors in the wiring harness. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.

5. Inspect the following components for damage, corrosion, and incorrect attachment:

   • Battery posts

   • Alternator

   • Breaker

   • Engine ground

   • Chassis ground

Expected Result:

All connectors, pins, and sockets are completely inserted and coupled. The harness and wiring is free of corrosion, of abrasion, and of pinch points. All connections and grounds are tight and free of corrosion.

Results:

• OK - Proceed to Test Step 3.

• Not OK -

  Repair: Repair the circuit.

  Verify that the repair eliminates the problem.

  STOP

Test Step 2. CHECK THE ETHER CANISTERS

1. Turn the circuit breaker for the battery to the OFF position.

2. Turn the ECS to the OFF/RESET position.

3. Remove the ether canister(s) from the ether solenoid(s). Determine if the canister contains any ether.

Expected Result:

The ether canisters must contain a sufficient amount of ether for the ether injection system in order to operate properly.

Results:

• OK - The canister contains a sufficient amount of ether. Proceed to Test Step 3.

• Not OK - The ether canister is empty.

  Repair: Replace the ether canister. Verify that ether can be injected after replacing the empty canister.

  If the problem has not been eliminated proceed to Test Step 3.

Test Step 3. CHECK THE STARTING AID SWITCH STATUS ON CAT ET

1. Remove the ether canister from the ether solenoid.

2. Connect the Caterpillar Electronic technician (ET) to the service tool connector.

3. Turn the ECS to the STOP position.

4. Press the starting aid switch to "MANUAL". Observe the "Starting Aid Switch Status" on Cat ET.

Expected Result:

When the starting aid switch is pressed, Cat ET displays the status of the starting aid switch as ON.

When the starting aid switch is not pressed, Cat ET displays the status of the starting aid switch as OFF.

Results:

• OK - The starting aid switch is operating correctly. Proceed to Test Step 4.

• Not OK - The ECM is not properly reading the signal from the starting aid switch. Proceed to Test Step 5.

Test Step 4. CHECK THE RESISTANCE OF THE ETHER START VALVE

1. Disconnect J37/P37 (Ether solenoid connector).

2. Turn the ECS to the OFF/RESET position.

3. Measure the resistance between J37:1 and J37:2.

4. Reconnect J37/P37 (Ether solenoid connector).

Expected Result:

The resistance is less than 8 Ohms.

Results:

• OK - Proceed to Test Step 6.

• Not OK - The relay is faulty.

  Repair: Replace the relay.

  Verify that the repair eliminates the problem.

  STOP

Test Step 5. BYPASS THE ETHER STARTING AID SWITCH

1. Turn the ECS to the OFF/RESET position.

2. Remove wire F720-GN(Green) (Starting aid switch) and wire 998-BR(Brown) (Digital return) from the starting aid switch.

3. Turn the ECS to the STOP position. Observe the status of starting aid switch on Cat ET.

4. Turn the ECS to the OFF/RESET position and short wire F720-GN(Green) (Starting aid switch) to wire 998-BR(Brown) (Digital return).

5. Turn the ECS to the STOP position and observe the status of starting aid switch on Cat ET.

Expected Result:

When the wires are shorted, Cat ET displays the status of the starting aid switch as ON.

When the wires are not shorted, Cat ET displays the status of the starting aid switch as OFF.

Results:

• OK - The starting aid switch is not operating correctly.

  Repair: Replace the starting aid switch.

  Verify that the repair eliminates the problem.

  STOP

• Not OK - The starting aid switch is operating correctly. Proceed to Test Step 7.

Test Step 6. CHECK THE SUPPLY VOLTAGE TO THE ETHER START VALVE

Illustration 2	g00743804
J1/P1 breakout

Note: The ether canister must be removed prior to activating this test.

1. Turn the ECS to the STOP position.

2. Access the diagnostic override screen on Cat ET and activate the ether system.

   Note: The diagnostic override will only activate the ether relay for three seconds.

3. Measure the supply voltage at J37:1 and J37:2.

Expected Result:

The supply voltage is 24.0 ± 8.0 VDC.

Results:

• OK - Proceed to Test Step 8.

• Not OK - The ECM is not reading the switch input properly.

  Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.

  Verify that the repair eliminates the problem.

  STOP

Test Step 7. CHECK FOR SHORTS IN THE HARNESS

1. Disconnect J1/P1 ECM connector. Remove wire F720-GN(Green) (Starting aid switch) and wire 998-BR(Brown) (Digital return) from the starting aid switch.

2. Measure the resistance between P1:25 (Starting aid switch) and P1:29 (Digital return).

3. Measure the resistance between P1:25 (Starting aid switch) and engine ground. Also measure the resistance between P1:25 (Starting aid switch) and all the other pins in the P1 (ECM connector).

Expected Result:

The resistance is greater than 20,000 Ohms for each measurement.

Results:

• Ok - Proceed to Test Step 9.

• Not OK - There is a short in the harness between the starting aid switch and the ECM.

  Repair: Repair the wiring or replace the wiring. Verify that the repair has eliminated the problem.

  STOP

Test Step 8. CHECK RESISTANCE AT THE ETHER RELAY COIL

1. Turn the ECS to the OFF/RESET position.

2. Disconnect the wires on terminal 85 and terminal 86 of the ether relay.

3. Measure the resistance between the ether relay terminals 85 and 86.

4. Reconnect the wires to the ether relay.

Expected Result:

The resistance is 360 ± 100 VDC.

Results:

• OK - Proceed to Test Step 9.

• Not OK - The ether relay is faulty.

  Repair: Replace the ether relay. Verify that the repair has eliminated the problem.

  STOP

Test Step 9. CHECK RESISTANCE THROUGH THE HARNESS

1. Remove wire F720-GN(Green) (Starting aid switch) and wire 998-BR(Brown) (Digital return) from the starting aid switch.

2. Short wire F720-GN(Green) (Starting aid switch) to wire 998-BR(Brown) (Digital return).

3. Measure the resistance between P1:25 and P1:29.

Expected Result:

The resistance is less than 10 Ohms.

Results:

• OK - The resistance in the harness is within acceptable limits. Proceed to Test Step 11.

• Not OK - There is an open circuit or excessive resistance in the harness.

  Repair: Repair the harness wiring or replace the harness wiring. Verify that the repair has eliminated the problem.

  STOP

Test Step 10. CHECK THE VOLTAGE AT THE ETHER RELAY

Note: The ether canister must be removed prior to activating this test.

1. Ensure that all connectors are connected to the wiring harness.

2. Turn the keyswitch to the ON position.

3. Proceed to the "Diagnostic Override Screen" in Cat ET.

4. Activate the ether injection system.

   Note: The diagnostic override will only activate the ether relay for three seconds.

5. Measure the voltage across terminal 86 (solenoid return) and terminal 85 (ether ON) of the ether relay.

Expected Result:

The voltage is 24.0 ± 8.0 VDC.

Results:

• OK - There is a problem with the ether relay contacts or there is a problem in the wire harness between terminal 30 of the ether relay and the ether start valve.

  Repair: Repair the wiring or replace the wiring. Verify that the repair has eliminated the problem.

  STOP

• Not OK - Proceed to Test Step 12.

Test Step 11. SHORT THE SWITCH INPUTS AT THE ECM

Illustration 3	g00743804

1. Disconnect J1/P1 (ECM connectors).

2. Remove wire F720-GN(Green) (Starting aid switch) and wire 998-BR(Brown) (Digital return) from the starting aid switch.

3. Short wire F720-GN(Green) (Starting aid switch) to wire 998-BR(Brown) (Digital return).

4. Turn the ECS to the STOP position.

5. Observe the status of starting aid switch on Cat ET.

6. Turn the ECS to the OFF/RESET position.

7. Remove the jumper wires from P1 (ECM connector).

8. Reconnect P1 (ECM connector).

9. Turn the ECS to the STOP position.

10. Observe the status of the starting aid switch on Cat ET.

11. Turn the ECS to the OFF/RESET position.

Expected Result:

When the wires are shorted, Cat ET displays the status of the starting aid switch as ON.

When the wires are not shorted, Cat ET displays the status of the starting aid switch as OFF.

Results:

• OK - There is a problem in the wiring between the starting aid switch and the ECM.

  Repair: Repair the circuit. Verify that the repair eliminates the problem.

  STOP

• Not OK - The ECM does not read the proper inputs for the starting aid switch.

  Repair: Replace the ECM. Refer to Troubleshooting, "Replacing the ECM".

  STOP

Test Step 12. CHECK THE VOLTAGE FOR THE ETHER RELAY AT THE ECM

Note: The ether canister must be removed prior to activating this test.

1. Proceed to the "Diagnostic Override Screen" in Cat ET.

2. Activate the ether injection system.

   Note: The diagnostic override will only activate the ether relay for three seconds.

3. Measure the voltage between P1:40 (Ether start valve relay) and P1:29 (Digital return).

4. Turn the ECS to the OFF/RESET position.

Expected Result:

The voltage is 24.0 ± 8.0 VDC.

Results:

• OK - There is an open circuit or there is excessive resistance in the harness.

  Repair: Repair the harness or replace the harness. Verify that the repair eliminates the problem.

  STOP

• Not OK - Proceed to Test Step 13.

Test Step 13. CHECK FOR SHORTS IN THE WIRING HARNESS FROM THE ETHER RELAY TO THE ECM

Illustration 4	g01068890
ECM connector P1

1. Disconnect J1/P1 ECM connector. Also, disconnect the wires at terminals 85 and 86 of the ether relay.

2. Disconnect the plug for the ether relay.

3. Measure the resistance between P1:40 (Ether start valve relay) and engine ground.

4. Measure the resistance between P1:40 (Ether start valve relay) and P1:29 (Digital return). Also, measure the resistance between P1:40 (Ether start valve relay) and all the other pins in the P1 (ECM connector).

5. Reconnect all wires and connectors.

Expected Result:

The resistance is greater than 20,000 Ohms.

Results:

• OK - Proceed to Test Step 14.

• Not OK - There is a short between the ECM and the ether relay.

  Repair: Repair the circuit. Verify that the repair has eliminated the problem.

  STOP

Test Step 14. CHECK THE VOLTAGE FOR THE ETHER RELAY AT THE ECM

Illustration 5	g01075986
J1/P1 breakout

Note: The ether canister must be removed prior to activating this test.

1. Turn the ECS to the STOP position.

2. Proceed to the "Diagnostic Override Screen" in ET.

3. Activate the ether injection system.

   Note: The diagnostic override will only activate the ether relay for three seconds.

4. Measure the supply voltage between P1:40 (Ether start valve relay) and P1:29 (Digital return).

5. Measure the voltage between P1:40 (Ether start valve relay) and engine ground.

Expected Result:

The voltage is 24.0 ± 8.0 VDC.

Results:

• OK - The ECM is supplying the correct voltage. There may be an open circuit or a short circuit in the harness.

  Repair: The ether injection system may have an intermittent electrical problem. Refer to Troubleshooting, "Electrical Connectors - Inspect". Verify that the repair eliminates the problem.

  STOP

• Not OK - The ECM is not supplying the correct voltage.

  Repair: Verify your results. Replace the ECM. Refer to Troubleshooting, "Replacing the ECM" before replacing the ECM.

  Verify that the repair eliminates the problem.

  STOP