Views: 43 Author: Site Editor Publish Time: 2022-04-15 Origin: Site
The Cummins ISF 2.8 diesel engine of Gazelle Business vehicles uses a high-pressure common-pipe fuel system with an electronic control system.
The high pressure fuel line system consists of 4 main elements: gear fuel pump, high pressure pump, common high pressure fuel line and injectors.
The high pressure pump delivers fuel to the common high pressure fuel line regardless of engine speed.
Fuel under high pressure is stored in this fuel line, from where it is constantly supplied to the injectors.
The ECM regulates fuel delivery and injection timing by activating the injectors.
A water separating fuel filter is required on the fuel intake side. It is located outside the engine and contains a manual priming pump.
Fig.29. Cummins ISF 2.8 diesel fuel system diagram
1 - Fuel supply from the tank, 2 - Fuel filter, 3 - Fuel water separator drain pipe, 4 - Priming pump, 5 - Fuel supply to the fuel pump, 6 - High pressure fuel pump, 7 - Fuel supply into the common high pressure fuel line, 8 - Common high pressure fuel line, 9 - Fuel supply to the injectors, 10 - Nozzle, 11 - Draining fuel from the injectors, 12 - High pressure reducing valve, 13 - Drain pipe of the high pressure reducing valve, 14 - Drain fuel line, 15 - Draining fuel into the tank
The gear fuel pump of the Cummins ISF 2.8 diesel engine of the Gazelle Business car creates a pressure of about 303 - 1303 kPa, due to which the fuel is cleaned in the filter installed on the engine or outside it before entering the high-pressure fuel pump.
In this pump, the fuel pressure is increased to a level of 250 - 1600 bar in three radial pressure chambers.
The executive valve of the electronic fuel supply system, installed at the inlet to these chambers, regulates the volume of fuel entering them.
To do this, it uses signals from the ECM, which maintains the pressure in the common high pressure fuel line at the required level.
Fuel that does not enter the pressure chambers exits through the cascade bypass valve.
It directs part of the fuel under pressure into the channels of the lubrication system of the Cummins ISF 2.8 diesel high pressure pump and then drains the fuel into a tank that accumulates fuel and distributes it between the fuel lines of individual injectors.
It has a sensor that monitors the pressure created in it by the high pressure pump. The signal from this sensor is used by the ECM to control the delivery of the high pressure fuel pump.
In addition, there is a pressure reducing valve in the common fuel line.
It acts as a safety valve, relieving excess pressure if the pressure in the fuel line exceeds a predetermined level.
The fuel drained from the common high pressure fuel line is returned to the fuel tank through the return fuel line.
High pressure fuel pump injection pump Cummins ISF 2.8
Inspection and dismantling of injection pump Bosch Common Rail Cummins ISF 2.8 Gazelle Business:
- Clean all fittings before dismantling. Dirt ingress can damage the fuel system.
- Turn the starting switch to the ON position and operate the starter to check the operation of the high pressure fuel pump.
- Disconnect the fuel line to the common high pressure fuel line from the Cummins ISF 2.8 injection pump.
- Connect a clean hose to the outlet port of the high pressure fuel pump.
- Insert the other end of this hose into an empty container.
- Operate the starter for 30 seconds and measure the fuel pump delivery.
- Fuel pump delivery must be at least 45 ml in 30 seconds at 125 rpm or 53 ml in 30 seconds at 150 rpm.
If the supply of the high-pressure fuel pump Bosch Cummins ISF 2.8 during starter operation does not meet the minimum rate, do the following:
- Check that there is no air in the fuel.
- Check for blockages in the fuel inlet line.
- If these checks are correct, check the resistance of the electronic fuel control actuator valve.
- After replacing the EC actuator valve, remeasure the fuel pump delivery.
- If the minimum fuel supply is not correct, replace the pump.
- Connect the electrical connector of the Gazelle Kamens injection pump actuator and clear all fault codes using the diagnostic kit.
- If the engine does not start, measure the fuel flow through the fuel return line - this will help identify a malfunction of the high pressure fuel pump.
- A faulty drain line bypass valve or fuel pump may cause high fuel flow through the return line.
- Be sure to measure the fuel flow through the fuel drain line while the Kamens 2.8 diesel engine is idling.
- The fuel system leak test provided in the diagnostic kit can be used to pressurize the fuel system to detect a large leak.
- Remove the fuel drain quick fitting from the high pressure pump.
- To reduce the risk of fuel leakage from the combined return line from the common high pressure fuel line and injectors, it is necessary to close the flexible fuel return line with a fuel line plug.
- Fit the drain hose with quick-release fitting to the drain pipe of the Bosch Common Rail injection pump. Place the end of the fuel drain hose into the graduated cylinder.
- Start the Cummins ISF 2.8 diesel engine of Gazelle Business vehicles and idle it.
- When fuel begins to flow into the graduated cylinder, measure the flow rate for 30 seconds.
- The maximum flow rate for 30 seconds at rated idle (800 rpm) is 310.
- If the high pressure pump is out of specification, check for air in the fuel and resistance at the fuel inlet.
- If the results of these checks are correct, the fuel pump must be replaced.
- Clean all fittings before disassembly. Dirt ingress can damage the fuel system.
- Disconnect batteries. Disconnect and remove the fuel supply and return lines.
- Disconnect the fuel supply line (1) to the high pressure common line from the high pressure fuel pump and loosen the support brackets (2).
- Disconnect the electronic fuel control actuator harness connector (3).
- Remove the three flange bolts securing the Bosch injection pump.
- Remove the fuel pump from the timing gear housing.
Dismantling and assembling the Kamens 2.8 diesel injection pump
- Using a gear change tool, hold the fuel pump drive gear in place.
- Loosen the Cummins ISF 2.8 diesel injection pump drive gear nut by turning it counterclockwise. Do not remove it from the shaft.
- Place a bearing remover between the pump mounting flange and the drive gear.
- Lock the bearing remover.
- Install the puller on the bearing remover and the pump drive shaft.
- Turn the puller screw until the gear is separated from the drive shaft.
- Remove the fuel pump drive gear nut, lock washer and the gear itself from the fuel pump drive shaft.
- Check the drive shaft and gear for damage. Replace damaged parts.
- Check the O-ring for damage. Replace the O-ring if damaged.
- Check the seat of the O-ring for damage. Clean and repair all damaged surfaces.
- Check the timing gear housing, the injection pump hole for the Cummins ISF 2.8 diesel engine and the mounting studs for cracks.
- Replace all damaged parts.
- Before assembly, clean and dry the toe of the drive shaft and the seating surface of the drive gear.
- Wipe the drive shaft and gear with a lint-free cloth soaked in solvent. Do not touch the seating surfaces after wiping.
- Mount the drive gear on the drive shaft.
- Install the lock washer and gear nut, hand-tighten the nut.
- Using a fuel pump gear changer and a 1.25 mm pry bar, hold the fuel pump drive gear in place while tightening the gear nut.
Installation of injection pump Kamens 2.8 Gazelle Business cars
- Install the fuel pump on the timing gear housing.
- Insert and tighten the mounting bolts for the Cummins ISF 2.8 injection pump.
- Install the fuel feed line to the high pressure common line from the high pressure fuel pump and tighten the support brackets.
- Connect the electronic fuel control actuator harness connector.
- To avoid sparking, disconnect the negative (-) battery cable first and reconnect it last.
- Connect and install the fuel supply lines.
- Connect and install the fuel drain lines.
- Connect the electronic fuel control actuator harness connector.
- Connect batteries. Fill the fuel system.
