Measuring the diesel fuel return quantity of Bosch solenoid valve injectors
Measuring the diesel fuel return quantity of Bosch
solenoid valve injectors
Important: Common
rail systems are at a very high pressure. Assembly work must not
commence until at least 30 seconds have elapsed after turning off
the engine!
The injector return quantity measuring unit is used to determine
the quantity returning for Bosch solenoid valve injectors for
common rail systems.
It is possible to discover defective injectors whilst they are
still installed by determining the quantity returning. Too large a
quantity returning can have the following effects when driving the
vehicle:
- Engine starts badly
- Engine shuts off on its own
- Loss of power
The following preconditions must be present to check the
injector return quantity:
- Engine responds
- A sufficient quantity of diesel fuel in the tank in the grade
specified by the manufacturer
Important: When
working on the fuel system it is essential to ensure cleanliness as
even tiny dirt particles can lead to faults in engine operation or
in the fuel system.
Note: The mode of
procedure for the measurement of the quantity of diesel fuel
returning is shown on a Z 19 DT as an example. Proceed by analogy
for other engines.
Remove
1.
Open bonnet
2.
Remove engine cover
•
Lift off engine cover Note: Refit any
retaining rubbers, which may have become detached, to the engine
cover
3.
Place a collecting pan underneath
4.
Detach oil leak line
•
Detach 4x oil leak line from injector
–
Press 4x retaining clamp (1) in the direction of the arrow
•
Remove oil leak line
5.
Seal 4x oil leak line (1) with EN-47655-40 (2)
•
Clip in 4x EN-47655-40 into oil leak
line
6.
Attach 4x injector diagnostic unit EN-47655 (1) to injector (2)
•
Connect 4x measuring cylinder to injector Note: Connection must
engage audibly
Measure
Important: Position injector
diagnostic unit horizontally and securely.
7.
Measure diesel injector return quantity
•
Start engine
•
Let engine run until one of the measuring cylinders is filled
completely
•
Stop engine
•
The maximum permissible return quantity is 3x as large as the
smallest return quantity measured
8.
Example 1 shows return quantity measurement OK
Measuring cylinder of injector
Contents
1
41 ml
2
44 ml
3
50 ml
4
46 ml
Maximum permissible return quantity:
41 ml x 3 = 123 ml
All the injectors are in good order.
9.
Example 1 shows return quantity measurement Not OK
Measuring cylinder of injector
Contents
1
50 ml
2
18 ml
3
18 ml
4
10 ml
Maximum permissible return quantity:
10 ml x 3 = 30 ml
Injector 1 has too large a return quantity. It must be
replaced.
Install
Important: Disposal of fuel must
comply with the regulations
10.
Detach injector diagnostic unit EN-47655 from the injectors
•
Detach 4x measuring cylinder from injector
–
Press 4x retaining clamp
11.
Detach 4x EN-47655-40 from oil leak
line
•
Press 4x retaining clamp
12.
Attach oil leak line
•
Clip 4x oil leak line into injector Note: Retaining clamp
must engage audibly
