524 AND 1724 ELECTRICALLY POWERED GOVERNOR SYSTEMS Troubleshooting 524/1724 Electric Governor System Caterpillar

Introduction

This troubleshooting guide can be an aid for the service personnel to find the cause of existing problems. Several common problems are covered in the guide, but these problems are not arranged in any particular sequence.

Identify your particular type of problem from the Troubleshooting Index, then go directly to that problem in the guide. However, when you begin the procedure for that problem, start at Step 1 and follow through the step by step procedure. The steps that follow in a particular problem provide a definite sequence to be followed for a logical, one by one elimination of many variables. These steps are arranged in order from the most probable/easiest to check, to the least probable/most complex to check.

Whenever the cause of the problem is found and corrected, stop the test (as shown by STOP). Do not continue through the complete procedure just because it is there.

Troubleshooting Index

Problem No. 1: Fuel Linkage Has Limited Travel, Binds, Or Takes Excessive Force

Step 1

Check Linkage Separately

Test Procedure:

Remove bolt that holds linkage to actuator lever. Now check movement of the fuel linkage by itself.

Test Results:

A. Linkage moves to full FUEL ON position correctly:

No mechanical problem with linkage. Go to Step 2.

B. Linkage does not move smoothly, does not reach stop screw, or takes excessive force:

Linkage is binding, or there is an engine problem. Repair linkage or engine. STOP.

Step 2

Check Actuator Separately

Test Procedure:

With linkage still disconnected from actuator lever, check lever movement by itself.

Test Results:

A. Actuator lever moves through its full range easily, but the lever travel is not greater than the fuel linkage travel at the full FUEL ON position.

Not a actuator mechanical problem. Make an adjustment of lever length or position on actuator terminal shaft to eliminate this condition. Now install linkage back to actuator lever. STOP.

B. Actuator does not move through full range smoothly, hangs up or takes excessive force.

Actuator has internal mechanical problem. Repair or replace actuator. STOP.

Problem No. 2: Engine Will Not Start

Step 1

Check For Actuator Travel

Test Procedure:

Crank the engine and check for Actuator Travel.

Test Results:

A. Actuator moves to FUEL ON position.

Governor is not the problem. Check for engine problem and make the repair. STOP.

B. Actuator does not move to FUEL ON position.

Go to Step 2.

Step 2

Measure Cranking rpm

Test Procedure:

Crank the engine and measure the cranking rpm.

Test Results:

A. Cranking speed is less than 75 rpm (100 rpm for hot starts).

Problem is in starting motor cranking circuit, engine, or engine has excessive load. Find and make the necessary repairs or corrections. STOP.

B. Cranking speed is more than 75 rpm (100 rpm for hot starts).

Go to Step 3.

Step 3

Manual Linkage Check

Test Procedure:

With engine stopped, manually move actuator lever and linkage to full FUEL ON position against stop screw.

Test Results:

A. Linkage moves through full travel smoothly until it is against stop screw, without binding or excessive force.

Check backlash according to Service Procedure B. If linkage backlash is acceptable, go to Step 4. If linkage backlash is not acceptable (more than specified wear limits), replace the bad components. STOP.

B. Linkage does not move through full travel to stop screw, is stuck, or has binding and takes excessive force to reach stop screw.

Go to Problem 1: Fuel Linkage Has Limited Travel, Binds, Or Takes Excessive Force.

Step 4

Actuator Voltage Check At Control

Test Procedure:

Crank the engine and measure actuator voltage at the 8290 Control across terminals T3 (+) & T4 (-). Observe polarity during measuring.

Test Results:

A. Less than 4 VDC measured.

Remove actuator leads from the 8290 Control terminals.

Now crank the engine and measure voltage at 8290 Control again.

1. If more than 4 VDC measured

Actuator or lead to actuator has a short and must be repaired. STOP.

2. If less than 4 VDC measured, but more than zero volts

Go to Step 6.

3. If zero volts measured

Go to Step 5.

B. More than 4 VDC measured

Check wire for continuity or replace actuator.

Step 5

Magnetic Pickup Voltage Check

Test Procedure:

Crank the engine and measure magnetic pickup voltage across terminals T5 & T6.

Test Results:

A. More than 1 VAC measured.

This is enough voltage to permit voltage to actuator circuit.

B. Less than 1 VAC measured.

a. Magnetic pickup problem. Go to Service Procedure C. If the magnetic pickup is not the problem, go to b.

b. Check Start/Fuel Limit setting in the control. Adjust potentiometer to full clockwise (CW) position for maximum voltage. STOP.

Step 6

Supply Voltage Check

Test Procedure:

While cranking the engine, measure the supply voltage at 8290 Control terminals T1 (+) and T2 (-).

Test Results:

A. Less than 15 VDC measured.

a. Check Start/Fuel Limit setting in the control. Adjust potentiometer to full clockwise (CW) position for maximum voltage. STOP.

b. Reduce the resistance from the battery to the control, or increase battery capacity. STOP.

B. More than 15 VDC measured.

Be sure polarity is correct.

Problem No. 3: Engine Will Not Carry Load (Low Power)

Step 1

Check Fuel Linkage Travel

Test Procedure:

With engine running at Rated Speed, increase load to maximum rating or until engine speed decreases to 50 rpm less than Rated. Check for fuel linkage travel.

Test Results:

A. Fuel linkage is against stop screw.

Increase Rated speed to permit full linkage travel at load point that engine is to be operated.

Low engine power with full linkage travel is caused by an engine problem, not a governor problem. Engine needs adjustment or repair (fuel setting, timing, poor quality fuel, etc). STOP.

B. Fuel linkage is not against stop screw.

Stop the engine. Go to Step 2.

Step 2

Manual Linkage Check

Test Procedure:

Disconnect fuel linkage from actuator lever. Check fuel linkage manually for high effort or binding. See Service Procedure B.

Test Results:

A. Linkage effort too high, or binding of linkage is found.

Find the source of defect and replace the bad linkage component. STOP.

B. Linkage effort is acceptable, and no binding is present.

Go to Step 3.

Step 3

Manual Actuator Lever Check

Test Procedure:

Manually check lever movement for high effort and full travel. Also check, with linkage held against stop screw, actuator lever has some extra travel beyond the linkage stop.

Test Results:

A. Actuator moves smoothly through the full range.

Not a mechanical problem, unless adjustment is necessary to permit extra travel of actuator lever (must have more travel range than linkage). Install linkage back to lever.

B. Actuator lever does not move full range, hangs up or takes excessive force.

Actuator has internal mechanical problem. Repair or replace actuator. STOP.