1995/03/01 Caterpillar

Improved Air Fuel Ratio Control (AFRC){1278}

Usage:

3306, 3306B, 3306C, 3406B and 3406C Truck Engines

Description of Change: The AFRC has been improved to help extend serviceable life of the diaphragm. The edges of components that contact the diaphragm have been smoothed to help prevent damage to the diaphragm. The new diaphragm seal washer will help reduce leakage. A new lock washer will help prevent loosening of the locknut (see the illustration).

Adaptable To: The new 106-6493 Diaphragm Seal Washer is a direct replacement for the former 7W-1691 Diaphragm Seal Washer. The new 115-3358 Lock Washer is an addition to the group. The AFRC improvements are effective with 3306C (9TL4656) Truck Engine and 3406C (8PN1, 3ZJ61100) Truck Engines. The new diaphragm washer and lock nut washer are adaptable to the AFRC's on 3306 and 3306B (63Z1-UP), 3306C (7RJ1-UP, 9TL1-UP), 3406B and 3406C (3ZJ1-UP, 5KJ1-UP, 4MG1-UP, 7FB1-UP) Truck Engines. When servicing the AFRC, smooth edges (see illustration) to provide a surface free of nicks and sharp edges.

1. New 115-3358 Lock Washer. 2. New 106-6493 Diaphragm Seal Washer. 3. Locations where the edges have been smoothed.

Caterpillar Information System:

1995/03/01 Governors Now Use New Low Mass Weight Carrier{1272}

1995/03/01 New Fuel Injection Pump Group{1251}

1995/02/01 Returning Core Engines For Full Refund {0374}

1995/02/01 New Inlet And Exhaust Valves Have Thinner Heads{1105}

1995/02/01 Fabricated Tool For Holding Air Compressor Drive Gear While Tightening Nut On Compressor Crankshaft{0600,1803}

1995/02/01 Special Electronic Control Module (ECM) Used With J1939 Data Link And Eaton Autoshift Transmission{1901}

1995/01/01 Electronic Timing Advance Improvements{1272,1253,1264}

1995/01/01 Description Of January 1995 (JAN95) Personality Module Changes {1902}

1995/01/01 Electronic Unit Injector (EUI) Replacement{1290}

1995/01/01 New Oil for All Engines Burning Low-Sulfur Fuel (0.05% or less) Except The 3600 Family Of Engines{1318}

1994/12/01 Black Painted Valve Covers Available{1107}

1994/12/01 New Exhaust Manifold Gasket Available{1059}

1995/03/01 Used Engine Oil From 1995 3406C (8PN) Truck Engines Is Darker In Color{1318}

1995/03/01 Jacket Water Pumps Now Include New Tapered Roller Bearings{1361}

1995/03/01 Do Not Install A Water Pump Designed For The 3406E Truck Engine On 3406, 3406B Or 3406C Engines{1361}

1995/03/01 Cracks In Phenolic Water Pump Impellers In Remanufactured Water Pumps{1364}

1995/04/01 Tampering With Turbocharger Wastegate{1057,1052}

1995/04/01 Identifying Fuel Injection Pump Check Valves For Compliance With Current Emissions Requirements {1251}

1995/04/01 New Needle Valve Body Corrects Low Idle Surge{1264}

1995/04/01 Handling Electronic Unit Injectors (EUI){1290}

1995/04/01 124-5572 Air Pressure Relief Valve Available{1803}

1995/04/01 Air Compressor Installation Procedure{1803}

1995/05/01 Requirement For FLASH Programming Capability{1900,1901}

1995/05/01 New Rear Power Take-Off (RPTO) Has 1.3:1 Ratio{1165}