Product Support Program For Improving Acceleration On Some 3116 Truck Engines Caterpillar

NOTE: The information supplied in this service letter may not be valid after the termination date of this program. Do not perform the work outlined in this Service Letter after the termination date without first contacting your Caterpillar product analyst.

NOTE: This Program can only be administered after a failure occurs. The decision whether to apply the Program is made by the dealer. When reporting the repair, use "PS0842" as the Part Number and "7755" as the Group Number. Use "96" as the Warranty Claim Description Code and use "Z" as the SIMS Description Code.

NOTE: This Revised Service Letter replaces the May 30, 1995 Service Letter. A change was made to the Affected Product.

Termination Date

Problem

Complaints of poor acceleration may be received on certain trucks and buses equipped with low-torque rating 3116 Truck Engines and Allison automatic transmissions.

Affected Product
Model & Identification Number

3116 (9GK1-20422)

Parts Needed

1 - 2M9780 Seal-O-Ring

Action Required

See the attached rework procedure.

Service Claim Allowances

NOTE: This is a 1.8-hour job. If the engine needs to be steam cleamed before performing the rework, an additional .3 hour of labor may be claimed.

Parts Disposition

Handle the parts in accordance with your Warranty Bulletin on warranty parts handling.

Attach.

(Rework Procedure)

Rework Procedure

NOTE: Refer to the 3116 Governor Service Manual, SENR6454, page 65, for the adjusting procedure for the fuel ratio control, Type V Governor. Also refer to the 3116 Truck Engine Device Manual, SEBR0551-01, pages 3-14, for the adjusting procedure for the fuel ration control setting.

1. Remove the 1054916 Access Plug on the side of the governor.

2. Remove the 4P2758 Boost Line between the intake manifold and fuel ratio control.

3. Remove the valve cover and install the 1U6680 Tool Group to measure on-engine rack.

4. Measure the fuel limited rack by quickly accelerating the engine. Record the reading of the dial indicator and repeat a number of time to ensure maximum rack is being read. This procedure is similar to the one on page 3-14 of the Service Manual, but does not require subtracting readings.

5. Use the 1U7299 Wrench (lock nut) and 1U7300 Wrench (adjusting screw) to increase the fuel ratio control limited rack to the proper value for the horsepower on the chart below. Values in the column labeled "Approx. Screw Turn" are the approximated amount the 1005737 Adjusting Screw must be turned (counterclockwise) to achieve the new setting.

NOTE: FARC limited rack values apply to both standard and low torque versions when both are offered.

NOTE: The adjustment collar for the adjusting screw has about 20 degrees of free movement before contacting its "stop". To ensure accurate setting, the 1U7299 and 1U7300 Wrenches must be turned together (clockwise) until the collar contacts its "stop" before tightening the lock nut.

6. Check the fuel ration control limited rack (Step 4) again and reset it if necessary.

7. Remove the rack measuring tooling.

8. Install the valve cover.

9. Replace the boost line (checking to verify the orificed fitting is open).

10. Install the access plug on the side of the governor using a new 2M9790 Seal-O-Ring.