3176C, 3406E and 3456 Industrial Engines Troubleshooting – Ether Starting Aid – Test

System Operation Description:

Use this procedure to troubleshoot any suspect problems with the ether injection system.

The ether injection system is used to improve the cold weather starting capability of the engine. The Electronic Control Module (ECM) controls the ether injection system. The ether injection system can operate in a automatic mode or a manual mode.

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

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

 

• Engine coolant temperature is between −40 °C (−40 °F) and 10 °C (50 °F).
• Engine speed is between 30 rpm and 1500 rpm.

Manual mode is activated by pressing the starting aid switch. In the manual mode, a single shot of ether is injected when the ether switch is actuated. The quantity of ether that is injected is controlled by the ECM. In the manual mode, the ether injection system is enabled when the following conditions are satisfied:

In the manual mode, the ether is turned on for three seconds.

 

• The starting aid switch is placed in the MANUAL position.
• Engine speed is between 30 rpm and 1500 rpm.
• Engine coolant temperature is less than 66 °C (151 °F).

Illustration 1 g01433515
Schematic for the ether system

Breathing ether vapors or repeated contact of ether with skin can cause personal injury. Personal injury may occur from failure to adhere to the following procedures.

Use ether only in well ventilated areas.

Do not smoke while changing ether cylinders.

Use ether with care to avoid fires.

Do not store replacement ether cylinders in living areas or in the operator’s compartment.

Do not store ether cylinders in direct sunlight or at temperatures above 49 °C (120 °F).

Discard cylinders in a safe place. Do not puncture or burn cylinders.

Keep ether cylinders out of the reach of unauthorized personnel.

To avoid possible injury, be sure the brakes are applied and all controls are in Hold or Neutral when starting the engine.

Test Step 1. Check the Ether Canisters for Fluid

 

1. Remove electrical power from the ECM.

 

2. Remove the ether canister from the ether solenoid. Determine if the canister contains any ether.

Expected Result:

The ether canister is not empty.

Results:

 

• OK – The ether canister is not empty. Remove the ether canister from the ether solenoid for the remainder of this test. Proceed to Test Step 2.
• Not OK – The ether canister is empty.Repair: Replace the empty ether canister with a full ether canister. Retry the system.STOP

Test Step 2. Inspect Electrical Connectors and Wiring

 

1. Remove electrical power from the ECM.

Illustration 2 g01139425
ECM
(1) J1/P1 connectors
(2) J2/P2 connectors

2. Thoroughly inspect connectors (1) and (2). Thoroughly inspect the circuit that is associated with the starting aid. Refer to Troubleshooting, “Electrical Connectors – Inspect” for details.

Illustration 3 g01431179
P1 ECM connector
(P1-13) Starting aid switch
(P1-34) Ether control relay

3. Perform a 45 N (10 lb) pull test on each of the wires in the ECM connector that are associated with the ether injection system.

 

4. Check the allen head screw on each ECM connector for the proper torque. Refer to Troubleshooting, “Electrical Connectors – Inspect” for the correct torque values.

 

5. Check the harness and the wiring for abrasion and for pinch points from the ether injection solenoid to the ECM. Verify that all connections and grounds are tight and free of corrosion.

Expected Result:

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

Results:

 

• OK – The connectors and wiring appear to be OK. Proceed to Test Step 3. 
• Not OK – The connectors and/or wiring are not OK.Repair: Repair the circuit.Verify that the repair eliminates the problem.

  STOP

Test Step 3. Check the Starting Aid Switch Status

 

1. Connect the Caterpillar Electronic Technician (ET) to the service tool connector.

 

2. Restore electrical power to the ECM.

 

3. 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 7. 
• Not OK – The ECM is not reading the input from the starting aid switch. Proceed to Test Step 4.

Test Step 4. Short the Switch Wires

 

1. Remove electrical power from the ECM.

 

2. Remove the wires from the starting aid switch.

 

3. Restore electrical power to the ECM.

 

4. Create a short with the wires from the starting aid switch. View the status of the starting aid switch on Cat ET.

 

5. Return the wiring to the original configuration.

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 ECM is receiving the correct switch input. There is a problem with the switch.Repair: Replace the starting aid switch.Verify that the repair eliminates the problem.

  STOP

   

• Not OK – The ECM is not receiving the correct switch input. Proceed to Test Step 5.

Test Step 5. Short the Switch Inputs at the ECM

 

1. Remove electrical power from the ECM.

 

2. Disconnect the J1/P1 ECM connector.

 

3. Fabricate a jumper wire that is long enough to create a short between the ECM connector and -Battery. Crimp a connector socket to one end of the jumper wire.

 

4. Remove the wire from terminal location P1-13 (starting aid switch) at the ECM connector. Install one of the jumper wire into this terminal location.

 

5. Connect the J1/P1 ECM connector.

 

6. Short the jumper wire in terminal P1-13 (starting aid switch) to -Battery.

 

7. Restore electrical power to the ECM.

 

8. Observe the results on the “Status” screen of Cat ET.

 

9. Remove electrical power from the ECM.

 

10. Remove the jumper wire.

Expected Result:

When the wire is shorted, Cat ET displays the status of the starting aid switch as “On”.

When the wire is not shorted, Cat ET displays the status of the starting aid switch as “Off”.

Results:

 

• OK – The ECM is reading the switch input properly. There may be a problem in the wiring between the switch and the ECM. Proceed to Test Step 6. 
• Not OK – The ECM is not reading the switch input properly.Repair: Replace the ECM. Refer to Troubleshooting, “ECM – Replace” before replacing the ECM.Verify that the repair eliminates the problem.

  STOP

Test Step 6. Check the Wiring Harness from the Starting Aid Switch to the ECM

 

1. Verify that the electrical power is removed from the ECM.

 

2. Disconnect the J1/P1 ECM connector.

 

3. Short the wires from the starting aid switch.

 

4. Disconnect the connector for the starting aid switch.

 

5. Measure the resistance between the terminals at the starting aid switch.

 

6. Return the wiring to the original configuration.

Expected Result:

The resistance does not indicate an open circuit.

Results:

 

• OK – The resistance does not indicate an open circuit. Proceed to Test Step 7. 
• Not OK – The resistance indicates an open circuit. There is a problem in the harness between the starting aid switch and the ECM.Repair: Repair the circuit.Verify that the repair eliminates the problem.

  STOP

Test Step 7. Check the Voltage from the Ether Start Relay

 

1. Remove electrical power from the ECM.

 

2. Connect Cat ET to the service tool connector.

 

3. Disconnect the wire from terminal 87 of the ether relay.

 

4. Fabricate a jumper wire that is long enough to provide a test circuit from -Battery to the ether relay.

 

5. Restore electrical power to the ECM.

 

6. Select the “Diagnostic Tests” on Cat ET.

 

7. Select the “Override Parameters” screen on Cat ET.

 

8. Activate the ether override and observe the voltmeter while ether injection is activated.Note: The ether override will activate the solenoid for ten seconds. The measurement must be taken within this time period.

 

9. Measure the voltage between terminal 87 of the ether relay and -Battery.

 

10. Remove electrical power from the ECM.

 

11. Restore the original wire to terminal 87 of the ether relay.

Expected Result:

The supply voltage is at least 11 VDC for a 12 volt system. The supply voltage is at least 22 VDC for a 24 volt system.

Results:

 

• OK – The voltage is within the range. The start relay is OK. Proceed to Test Step 8. 
• Not OK – The voltage is not within the range. Proceed to Test Step 9.

Test Step 8. Check the Voltage at the Starting Aid Solenoid

 

1. Disconnect the connector from the starting aid solenoid.

 

2. Connect a voltmeter between terminal 1 and terminal 2 on the harness side of the connector.

 

3. Restore electrical power to the ECM.

 

4. Select the “Diagnostic Tests” on Cat ET.

 

5. Select the “Override Parameters” screen on Cat ET.

 

6. Activate the ether override and observe the voltmeter while ether injection is activated.Note: The ether override will activate the solenoid for ten seconds. The measurement must be taken within this time period.

 

7. Measure the voltage at the connector for the starting aid solenoid.

 

8. Remove electrical power from the ECM.

 

9. Reconnect all connectors.

Expected Result:

The supply voltage is at least 11 VDC for a 12 volt system. The supply voltage is at least 22 VDC for a 24 volt system.

Results:

 

• OK – The voltage is within the range.Repair: Voltage is present at the connector for the starting aid solenoid. Verify the continuity of the starting aid solenoid’s return wire. If the return wire is OK there is a problem with the solenoid. Replace the starting aid solenoid.

  STOP

   

• Not OK – The voltage is not within the range.Repair: There is a problem in the harness between the ether relay and the starting aid solenoid. The problem may be in the ground circuit for the starting aid solenoid. Check the wiring harness and the connectors for problems. Repair the harness and/or the connectors. Replace parts, if necessary.

  STOP

Test Step 9. Check the Control Input Voltage at the Ether Start Relay

 

1. Restore electrical power to the ECM.

 

2. Select the “Diagnostic Tests” on Cat ET.

 

3. Select the “Override Parameters” screen on Cat ET.

 

4. Activate the ether override and observe the voltmeter while ether injection is activated.Note: The ether override will activate the solenoid for ten seconds. The measurement must be taken within this time period.

 

5. Measure the voltage between terminals 85 and 86 of the ether relay.

 

6. Remove electrical power to the ECM.

Expected Result:

The supply voltage is at least 11 VDC for a 12 volt system. The supply voltage is at least 22 VDC for a 24 volt system.

Results:

 

• OK – The voltage is within the range. Control input voltage is reaching the ether relay. Proceed to Test Step 10. 
• Not OK – The voltage is not within the range. Control input voltage is not reaching the control relay. Proceed to Test Step 11.

Test Step 10. Check the Secondary Voltage to the Ether Relay

 

1. Fabricate a jumper wire that is long enough to provide a test circuit from the −Battery to the ether relay. Connect one end of the wire to −Battery.

 

2. Restore electrical power to the ECM.

 

3. Measure the voltage between terminal 30 of the ether relay and the −Battery.

Expected Result:

The supply voltage is at least 11 VDC for a 12 volt system. The supply voltage is at least 22 VDC for a 24 volt system.

Results:

 

• OK – The voltage is within the range.Repair: The wiring and the connectors to the ether relay are OK. There is a problem with the ether relay. Replace the ether relay. Verify that the ether starting aid is operating correctly.

  STOP

   

• Not OK – The voltage is not within the range.Repair: The problem is in the harness between the +battery and the ether relay. There may be a problem with a connector. Repair the harness and/or the connectors. Replace parts, if necessary.

  STOP

Test Step 11. Check the Operation of the ECM

 

1. Remove electrical power to the ECM.

 

2. Fabricate a jumper wire that is long enough to measure voltage from a terminal at the ECM connector. Crimp a connector socket to one end of the jumper wire.

 

3. Disconnect the J1/P1 ECM connectors.

 

4. Remove the wire from terminal location P1-34 at the ECM connector. Install the wire jumper into this terminal location.

 

5. Connect the J1/P1 ECM connector.

 

6. Connect a voltmeter between the −Battery and the wire jumper in terminal P1-34.

 

7. Restore electrical power to the ECM.

 

8. Select the “Override Parameters” screen on Cat ET.

 

9. Activate the ether override and observe the voltmeter while ether injection is activated.Note: The ether override will activate the solenoid for ten seconds. The measurement must be taken within this time period.

 

10. Monitor the voltage on the voltmeter.

 

11. Remove electrical power to the ECM.

 

12. Restore the wiring to the original configuration.

Expected Result:

The supply voltage is at least 11 VDC for a 12 volt system. The supply voltage is at least 22 VDC for a 24 volt system.

Results:

 

• OK – The voltage is within the range. The output driver for the ether relay at the ECM is OK. The problem is in the harness from the ECM to the ether relay. The problem may be in a connector. Repair the harness and/or the connector. Replace parts, if necessary. 
• Not OK – The voltage is not within the range.Repair: Replace the ECM. Refer to electronic troubleshooting Troubleshooting, “ECM – Replace”. Verify that the problem is resolved.

  STOP