Set up Procedure for the Low-Pressure Fuel System of 3600 and C280 Diesel Engines{1250} Caterpillar

Engine:

3606 (S/N: 8RB1-UP)

3608 (S/N: 6MC1-UP; 1ZD1-UP; 5PG1-UP; 8LL1-UP; 7WR1-UP)

3612 (S/N: NZA1-UP; 9RC1-UP; 9FR1-UP)

3616 (S/N: 1PD1-UP; RMN1-UP; 1FN1-UP)

C280-16 (S/N: NKB1-UP; TDX1-UP)

Marine Engine:

C280-12 (S/N: TSJ1-UP; RDW1-UP)

C280-6 (S/N: SCB1-UP; LDL1-UP)

C280-8 (S/N: PKA1-UP; NDT1-UP)

Introduction

Do not perform any procedure in this Special Instruction until you read this information and you understand this information.

This Special Instruction provides information for proper set-up of the low-pressure fuel system. A low-pressure fuel system that has been set up incorrectly can allow air in the system. Air in the system can cause hard starting, erratic engine operation, and can also erode the unit injectors. This procedure can be used on new and existing installations to check pressure and must be done with clean primary and secondary fuel filters.

Reference Material

ReferenceApplication and Installation Guide, LEBW4976, "Diesel Fuels and Diesel Fuel Systems"

ReferenceApplication and Installation Guide, LEBW4985, "Diesel Engine Commissioning - 3600/C280"

ReferenceOperation and Maintenance Manual, SEBU7003, "Cat 3600 Series and C280 Series Diesel Engine Fluids Recommendations"

ReferenceSystems Operation/ Testing and Adjusting, SENR3599, "3606 and 3608 Engines"

ReferenceSystems Operation/ Testing and Adjusting, SENR3593, "3612 and 3616 Engines"

ReferenceSystems Operation/ Testing and Adjusting, RENR5083, "C280 Marine Engines"

ReferenceSpecifications, SENR3598, "3606 and 3608 Engines"

ReferenceSpecifications, SENR3592, "3612 and 3616 Engines"

ReferenceSpecifications, RENR5082, "C280 Marine Engines"

ReferenceEngine News, SEBD9307, "New Specification For The Minimum Fuel Pressure At The Inlet To The Fuel Transfer Pump"

Required Tooling

Low-Pressure Fuel System Specifications

Inlet Fuel Pressure to the Transfer Pump (set at rated speed and load)

• No less than −20 kPa (−3 psi) and no greater than 100 kPa (14.5 psi)

• 50 kPa (7.25 psi) if a priming pump is used

Primary and Secondary Fuel Filter Differential Pressure

• 75 kPa (10.8 psi) maximum

Fuel System Pressure at the Pressure Regulator (set at rated speed and load)

• MUI: 550 ± 50 kPa (80 ± 7 psi)

• EUI: 820 ± 20 kPa (119 ± 3 psi)

Return Fuel Line Restriction Pressure

• Do not exceed 350 kPa (51 psi) at rated speed and load

Locations and Methods for Measuring the Pressures of the Low-Pressure Fuel System

Illustration 1	g03325145
Front View of a typical fuel inlet lines group (A) Fuel inlet port (B) Test port for the fuel supply pressure (C) Fuel transfer pump (D) Test port location for system pressure

Inlet Fuel Pressure to the Transfer Pump (set at rated speed and load)

1. Install a 6V-3965 Fitting into Port (B) using a 214-7568 O-Ring Seal

   Note: The inlet pressure to the fuel transfer pump can affect overall system pressure. All filters or water separators before the transfer pump must be new and clean prior to setting the system pressure at the fuel pressure regulator.

2. Connect the 6V-7830 Pressure Gauge to the fitting installed in the previous step.

3. Set the engine to rated speed and load. Record the fuel pressure, and refer to the specifications above.

Primary and Secondary Fuel Filter Differential Pressure

Primary and secondary fuel filter differential pressures are determined by the pressures from both sides of the fuel filters. This measurement will monitor fuel filter cleanliness and determine when the fuel filters require changing.

Filter replacement will vary depending on fuel quality. Fuel quality can change with each shipment of fuel so monitoring the filter differential is necessary to obtain maximum filter life.

Too high of a differential can cause air bubbles in the fuel system and if not corrected will lead to poor performance and injector damage. After the measurements are taken, refer to the specification above for the maximum allowable differential pressure.

Primary filters or water separators should be properly sized to meet the flow requirements of the engine or engines as well as fuel being returned to the tank. Reference Table 4 for the flow requirements.

Fuel System Pressure

1. Install a 6V-3965 Fitting into Port (D) using a 214-7568 O-Ring Seal

   Note: The inlet pressure to the fuel transfer pump can affect overall system pressure. All filters or water separators before the transfer pump must be new and clean prior to setting the system pressure at the fuel pressure regulator.

Show/hide table



Illustration 2	g03327931
6V-7830 Pressure Gauge installed on the engine

2. Connect the 6V-7830 Pressure Gauge to the fitting installed in the previous step.

3. Set the engine to rated speed and load. Record the fuel pressure, and refer to the specification above.

   Note: If multiple engines are using the same fuel manifold or day tank, operate and load all engines to set the system fuel pressure. Multiple engines operating on the same fuel tank or manifold will affect the pressure depending on the number of engines running and the fuel demand.

   Note: If rated speed and load cannot be achieved, use Tables 2 and 3 to determine the pressure to set at the regulator. This setting is based on load and zero restriction to the transfer pump.

4. With the 6V-7830 Pressure Gauge connected to the fuel pressure regulator, adjust the regulator until the desired pressure is obtained.

Return Fuel Line Restriction Pressure

This pressure is taken after the fuel pressure regulator in the customer supplied piping. Measure this pressure directly after the fuel pressure regulator, before any other fuel system components.

Note: All pressures can be documented on the attached Check Sheet (Illustration 3) for future reference.

Illustration 3	g03325164