1998/02/16 Caterpillar

Cold Cylinder Cutout Strategy Added To The Electronic Control Module (ECM) Software {1902}

Usage:

D11N (4HK),
D11R (8ZR) Track-Type Tractors;
776C (2TK),
784B (5RK) Off-Highway Tractors;
777C (4XJ),
785B (6HK),
789B (7EK),
793B (1HL) Off-Highway Trucks;
5130 (7TJ),
5230 (7LL) Excavators

Reference: Special Instruction; SEHS9868, Aug 1997; "New Personality Modules For 3500 EUI Engines Used In Off-Highway Trucks"

This article replaces the article with the same title on Page 33 of the September 15, 1997 issue. The article in the September 15, 1997 issue contained some incorrect information. A computer error caused the cold cylinder cutout strategy to be left out of the personality modules for the 785B, 789B and 793B Trucks. This article contains the personality module part numbers that contain operational cold cylinder cutout strategy.

Description of Change: The Cold Cylinder Cutout Strategy provides a means for the ECM to reduce white smoke output on cold start up, minimize the time at retarded timing (cold mode), and reduce the use of ether injection. The Cold Cylinder Cutout Strategy is added to the software for the above machines powered by 3508, 3512, and 3516 EUI Engines.

During cold start up and during periods of extended time at low idle, the ECM automatically turns off one electronic unit injector at a time. The ECM determines if the cylinder is firing by checking the rack. If the cylinder is firing, the ECM turns the electronic unit injector ON. If the cylinder is not firing, the electronic unit injector remains turned OFF, which reduces white smoke (unburned fuel).

NOTE: When cylinder cutout is active, the engine will sound as though it misfires. This is a normal cylinder cutout condition and does not indicate the need for any type of engine repair.

Adaptable To: The change is adaptable back to first production. See the following chart for effectivity:

Application

The following conditions are necessary for cold cylinder cutout activation in the D11N and D11R:

NOTE: A factory password is necessary for D11N and D11R due to a personality module mismatch on 3508 8ZR1-Up EUI Engines.

* The engine speed is below 1350 rpm.

* The fuel position is less than 130.

* The desired speed does not vary more than ± 50 rpm.

* The jacket water temperature is below 63°C (145°F).

NOTE: The Cold Cylinder Cutout Strategy is activated ten seconds after the engine starts and reaches idle speed if the above conditions are met. The Cold Cylinder Cutout Strategy will also activate after ten minutes of idling if the same conditions are met.

NOTE: The new Personality Module on the EUI engines used in the 776C, 777C, 784B, 785B, 789B, and 793B must be used in conjunction with a 103-6091 Pressure Sensor Group. If the engine uses a 6V-1944 Pressure Sensor Group, it must be replaced by a new 103-6091 Pressure Sensor Group. The 103-6091 Pressure Sensor Group has an expanded range and is more accurate at high boost. The 8T-8732 Connector Receptacle from the engine wiring harness must be replaced by the 3E-3370 Connector Receptacle Assembly and 3E-3371 Receptacle Lock Wedge, in order to secure the plug in the correct position. The 103-6091 Pressure Sensor Group is effective with 3508 (7YG1316-Up, 5TL118-Up), 3512 (4WJ638-Up, 6FL75-Up), 3516 [789B, (2PK861-Up, 7CL205-Up)], and [793B, (2PK-814-Up, 7CL196-Up] EUI Engines. Some EUI engines may have already been updated with the 103-6091 Pressure Sensor Group. When switching to the new personality module, it is important to check to see if the 103-6091 Pressure Sensor Group is installed.

The following conditions will deactivate the Cold Cylinder Cutout Strategy in the D11N and D11R:

* The engine speed is above 1350 rpm.

* The jacket water temperature is above 70°C (158°F).

* If the engine speed falls more than 50 rpm below low idle, the Cold Cylinder Cutout deactivates for 10 minutes.

* The fuel position is greater than 130.

* The Electronic Control Analyzer And Programmer (ECAP) or Electronic Technician (ET) Service Tool cutout test is activated.

* If the engine speed varies more than ± 50 rpm from when the Cold Cylinder Cutout began.

The following conditions are necessary for cold cylinder cutout activation in the 776C and 784B Off-Highway Tractors and the 777C, 785B, 789B, and 793B Off-Highway Trucks:

* The parking brake is engaged.

* The transmission is in neutral.

* The machine ground speed is zero.

* The jacket water temperature is below 63°C (145°F)

The following conditions will deactivate the Cold Cylinder Cutout Strategy in the 776C and 784B Off-Highway Tractors and the 777C, 785B, 789B, and 793B Off-Highway Trucks:

* The parking brake is disengaged.

* The throttle pedal is depressed by more than 25 percent of its travel.

* The transmission is in gear.

* The machine ground speed is above zero.

* The jacket water temperature is above 70°C (158°F).

* The ECAP or ET Service Tool cutout test is activated.

NOTE: If the engine speed is at low idle for ten seconds and then the engine speed falls more than 100 rpm (50 rpm for 776C and 777C) below low idle, the Cold Cylinder Cutout deactivates for 10 minutes.

The following conditions are necessary for cold cylinder cutout activation in the 5130 and 5230 Excavators:

* The engine speed is below 1400 rpm.

* The average fuel position is less than 90 for 5130, and 110 for 5230 over a one second interval.

* The jacket water temperature is below 63°C (145°F)

The following conditions will deactivate the Cold Cylinder Cutout Strategy in the 5130 and 5230 Excavators:

* The engine speed is above 1450 rpm.

* The jacket water temperature is above 70°C (158°F)

* If the engine speed falls more than 50 rpm below low idle, the Cold Cylinder Cutout deactivates for 10 minutes.

* The average fuel position is greater than 90 for 5130 and 110 for 5230 over a one second interval.

* The ECAP or ET Service Tool cutout test is activated.