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Technology Info >> The debugging points of the VE Diesel fuel injection pumps


1.       Preparation before debugging

Install the VE pumps on the test bench and inject the diesel oil with a pressure of 0.035 MPa into the inlet pipe joint; Install a pressure gauge with a range of 0~1.0MPa between the oil return pipe joint and the pump body, and then connect the oil return pipe; Connect high-pressure fuel pipe and fuel injector. The specification of high-pressure oil pipe is 6×2mm, the length of the first and third cylinders is 420mm, and the length of the second and fourth cylinders is 430mm. The injection pressure of the standard injector is 17.2+0.3MPa, the diameter of the orifice is 0.4mm, and the temperature of the test oil is 38~42°C. In addition, the solenoid valve is powered by a 10-12V voltage.

2.       The requirements of debugging for VE Diesel fuel injection pumps.

1)     Inspection and debugging of the pre-stroke (from the bottom dead center) of the VE4/11F1900R294 fuel injection pump is specified as 0±0.02mm. During the inspection, install a transparent oil drain pipe on the screw hole of the screw plug at the upper end of the fuel injection pump, and slowly rotate the fuel pump drive shaft so that the oil just flows into the oil pipe, but does not flow out from the oil pipe. Then, remove the oil drain pipe and replace it with a dial gauge to measure the position record reading in the fuel pump plunger. Turn the fuel pump drive shaft so that the plunger is at the bottom dead center, the left limit position. The position record reading of the diesel injection pump plunger is also measured with a dial gauge. The difference between the two readings is the pre-stroke. If the pre-stroke does not meet the specified value, adjust it with the adjustment shim of the plunger. If the plunger shim is replaced, the pre-stroke should also be checked and adjusted as described above.

2)     Adjustment of the internal pressure of the fuel injection pump: adjust the VE pump speed to 1500r/min, the inlet pressure of the LDA unit is 0.1MPa, and the internal chamber pressure is 0.6-0.66MPa. If the specified value is not met, the pressure regulating spring seat of the oil pump pressure regulating valve in the VE pump can be adjusted. At the same time, check whether the VE pump internal cavity pressure meets the corresponding requirements at other specified speeds. See Table 8-6.

3)    Adjustment of oil return: Check the specified value of oil return at the specified speed. The amount of oil return interacts with the pressure of the regulating valve of the feed pump in the VE pump, and the both must be checked repeatedly.

4)     Full load fuel oil adjustment: adjust the VE pump speed to 1900r/min. When the LDA unit inlet pressure is 0.1MPa, press the control handle against the high speed limit screw to check whether the fuel supply of the VE pump is satisfied. Otherwise use the maximum fuel supply adjustment screw adjustment, the screwing oil supply increases; the oil supply is reduced. At the same time, check whether the difference in oil supply of each cylinder meets the requirements. In addition, it is also necessary to check the full load of oil at other specified speeds. It is necessary to explain that the fuel supply amount of the fuel injection pump and its internal cavity pressure affect each other. After adjusting the fuel supply amount of the fuel injection pump, it is necessary to re-examine whether the internal cavity pressure exceeds the specified value. The debugging parameters of the Iveco diesel VE distribution pump are shown in Table 8-6.

8-6 The debugging parameters of VE pumps

VE pumpVE4/11F1900R294  Injection pressure24+0.8MPa  Minimum speed of diesel engine750±25r/min

Static fuel injection advance angle4.5°±45’      Oil pressure of test:0.035MPa     Diesel engine:Iveco 8140


Test content

Test condition

Test parameters


Fuel injection starting


Pre-stoke(from top dead center)0±0.02mm


The oil supply pressure of feed pumps

Rotating speed:1150r/min

LDA intake pressure: 0.1MPa


Adjustment value:0.6~0.66MPa


Full load oil in pressurized state

Rotating speed: 1900r/min

LDA intake pressure: 0.1MPa

Rotating speed:550r/min

49.5~50.5cm3/1000 average value

Maximum oil mass error 3cm3

30.5~31.5cm3/1000 average value


Starting characteristics

Rotating speed:100r/min

60~90cm3/1000 average value


Oil mass of flameout(mechanical)

Rotating speed:2300r/min

Rotating speed:450r/min

2cm3/1000 average value

5cm3/1000 average value


Fuel injection advance angle automatic regulator stroke

Rotating speed:1150r/min



LDA intake pressure:0.1MPa






Oil mass supply for Minimum speed

Rotating speed:400r/min



5.0~15.0cm3/1000 average value

30~38.0cm3/1000 average value

70cm3/1000 average value


Speed governing characteristics of the governor

Rotating speed: 375r/min

20.0~24.0cm3/1000 average value

Maximum oil mass error 3cm3


Speed governor's maximum speed characteristics

Rotating speed: 2300r/min

LDA intake pressure:0.1MPa

1cm3/1000  average value


The oil supply pressure of feed pumps

LDA intake pressure:0.1MPa

Rotating speed: 1150r/min








Oil mass for different speed

Rotating speed: :r/min


1000 cm3  average value





























Assembly size




LDA Device stroke6.3mm

*——All rotating speeds are for  VE injection pump rotating speed


5)       Starting oil mass supply: adjust the VE pump rotating speed to 100r/min, check the oil mass supply of the VE pump, and meet the requirements.

6)       Function check of the oil stop device: Rotate the stop handle to the oil cut direction at the specified speed. The oil mass supply of the VE pump should be less than the specified value. See Table 8-6. The solenoid valve circuit is cut off at the specified speed, and the fuel supply of the VE pump should be less than the specified value.

7)       Debugging of the fuel injection advance angle automatic adjuster stroke: Remove the regulator cover and install the device of the regulator. The speed of the VE pump is adjusted to 1150r/min, and the inlet pressure of the IDA device is 0.1MPa. The regulator stroke is 1.6-2.0mm. If the specified value is not met, adjust the thickness of the adjuster adjustment shim or replace the adjuster spring. See Table 8-6.

8)       Adjustment of the working starting point of the LDA device: the steering handle is pressed against the high speed limit screw, the VE pump speed is adjusted to the specified value, and the compressed air of different pressure values is guided to the LDA device to check whether it starts to function under the specified compressed air pressure. Otherwise, adjust the gear adjustment.

9)       Adjustment of high-speed limit screw: Close the high-speed limit screw of the joystick and adjust the high-speed limit screw so that the starting speed is higher than the rated speed 20-30r/min, at the same time check whether the rotate speed of oil stopped meets the requirements.

10)   Adjustment of idle speed limit screw: Close the steering handle to the idle limit screw, adjust the speed of the VE pump to idle speed, adjust the idle limit screw, and make the oil supply of the feed pump reach the specified idle oil mass. Check the diesel oil supply of each cylinder. Within the specified range. Also check the oil stop speed in idle meets the requirements or not. See Table 8-6.

11)   KF size adjustment: KF size is the adjustment of the pretightening force of pull-off spring in the VE diesel pump plungers. Install the guide pin, the adjusting washer, the return spring upper seat, etc on the rotor head in the diesel fuel injection pump which are in the relative position of the original disassembly. The dial indicator is installed on a special probe, which is stalled on the detection screw hole of the ve diesel fuel injection pump. Measuring the distance between the top of the plunger and the end face of the plunger sleeve, when the return spring of plunger is not compressed, the above measured distance is the KF size, The KF size of the VE4/11F1900R294 fuel injection pump is 5.2~5.4mm. If the KF size does not match, the thickness of the adjusting washer in the guide pin needs to be changed. See Table 8-6 and Figure 8-27(a)(b).

12)   K size adjustment: After the KF size adjustment is passed, the guide pin, the adjustment washer, the seat of return spring, the return spring of plunger, the return spring, and the return lever spring of governor lever, O seal ring, the plungers the lower seat of return spring and oil control sliding sleeve are replaced on the rotor head according to the original disassembled relative position.Properly assembled in the rotor head so that the large end notch of the diesel plunger engages with the drive pin on the cam disc. Fix the rotor head to the pump body with a tightening torque of 11-13 N·m. Then use a special probe and a dial gauge to measure the distance between the top surface of the plunger and the end face of the plunger sleeve. This distance is the K size. The K size of the VE4/11F1900R294 fuel injection pump is 3.3mm.If the K size doesn’t match, you can use the shim of plunger to adjust the gasket. The thickness of the plunger adjustment shim is from 1.78 to 2.90 mm, which is a specification every 0.02 mm, and 56 types are available. See Table 8-6 and Figure 8-27(c)(d).

13)   MS size adjustment: Install the maximum oil supply adjustment screw and project the nail to the end face of the governor cover before disassembly. Fix the special tool to the pump body and keep the adjustment lever in contact with a dowel pin of the special tool. Then use a gauge to measure the gap between the sliding pin and the rod, which is the MS size, that is, the gap between the starter and the enrichment device. The MS size of the VE pump is 0.8 to 1.0 mm. If the MS size does not match, the sliding sleeve assembly on the adjuster assembly should be removed and the slip sleeve pin of the appropriate thickness should be replaced. See Table 8-6.

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