G3600 A4 Engines Engine Overspeeds Caterpillar


Engine Overspeeds
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1.1. Probable Causes
2.1. Recommended Actions

Use this procedure in order to troubleshoot an engine overspeed. Also, use this procedure if one of the following event codes is active or logged.

Table 1
J1939 Code and Description  Comments 
190-0
Engine Speed : High - most severe (3) 
The engine rpm has exceeded the trip point that is programmed into the Electronic Control Module (ECM) and the delay time has expired.
The ECM has determined that the detected speed is accurate.
The gas shutoff valve and the ignition are shut off.
The code is logged. 
190-15
Engine Speed : High - least severe (1) 
The engine rpm has exceeded the trip point that is programmed into the ECM and the delay time has expired.
The ECM has determined that the detected speed is accurate.
The code is logged. 
190-16
Engine Speed : High - moderate severity (2) 
The engine rpm has exceeded the trip point that is programmed into the ECM and the delay time has expired.
The ECM has determined that the detected speed is accurate.
The code is logged. 

------ WARNING! ------

Unburned gas in the air inlet and exhaust system may ignite when the engine is started. Personal injury and/or property damage may result.

Before starting an engine that may contain unburned gas, purge the unburned gas from the air inlet and exhaust system. Refer to the topic on purging unburned gas in the "Starting the Engine" section.


Probable Causes

  • Codes

  • Governor response

  • Trip point

  • Driven equipment

  • Air choke

Recommended Actions

Table 2
Troubleshooting Test Steps  Values  Results 

1. Check for Codes

A. Connect Cat® Electronic Technician (ET) to the service tool connector.

B. Look for active codes that are associated with the system for the event code.
 

Codes
 

Result: An associated code is active.

Repair: Troubleshoot any associated codes before continuing with this test.

Result: A code is active or logged.

Proceed to Test Step 2.
 

2. Check for Slow Governor Response

Note: If an engine overspeed occurs during start-up or when the load is reduced, the governor response may be slow.

A. Connect Cat ET.

B. Use Cat ET to monitor the following:

- "Speed Governor Adjustment"

C. Look for the engine response to the worst cases for step-loading and unloading.
 

Governor Response
 

Result: The governor response is OK.

Proceed to Test Step 3.

Result: The governor response is NOT OK. The undershoot or the overshoot of the engine speed is excessive.

Repair: Adjust the governor gain. Refer to Systems Operation, "Electronic Control System Parameters".

If the problem is not resolved, proceed to Test Step 3.
 

3. Check the Trip Point

Note: Do not program the trip point for engine overspeed higher than the maximum ratings of the driven equipment.

A. Verify that the trip point for the engine overspeed is properly programmed.
 

Trip Point
 

Result: The trip point is OK.

Proceed to Test Step 4.

Result: The trip point is NOT OK.

Repair: Change the trip point to an acceptable speed.

This parameter requires a factory password in order to change the trip point.

If the problem is not resolved, proceed to Test Step 4.
 

4. Inspect the Driven Equipment

A. Determine if the driven equipment has additional inputs of energy that could drive the engine beyond the rated rpm.
 

Driven Equipment
 

Result: The driven equipment is OK.

Proceed to Test Step 5.

Result: The driven equipment is NOT OK.

Repair: Make corrections to the installation in order to prevent the overspeed from recurring.

If the problem is not resolved, proceed to Test Step 5.
 

5. Check for Binding of the Air Choke Actuator

A. Remove the electrical power from the engine.

B. Move the actuator rod or the throttle plate while you feel the motion.
 

Air Choke
 

Result: The actuator rod or the throttle plate is binding.

Repair: Repair or replace damaged air choke components. Refer to Operation and Maintenance Manual, "Electrohydraulic Actuator - Recondition" for additional information.

Verify that the repair eliminated the problem.
 

If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).