Functional Description - Bosch 0 986 612 950 Manual Original

2.5 Overview of the injector return
quantity meter
 1: Injector return quantity meter
(1) Housing with 6 integrated graduated measuring cylinders
(2) Connector caps
(3) Plug connection with ball valve
(4) Hose assembly
(5) Hoisting strap with hook
2.6 Filling capacities of the graduated
measuring cylinders
458919-09_shd
 2: Filling quantities at the graduation marks

2.7 Functional description

The 0 986 612 950 is connected to the injectors
installed in the engine. If the plug-in connectors
of the 0 986 612 950 cannot be attached directly
to the injector, appropriate adapter hose assem-
blies must be used. The return quantity from the
individual injectors is collected in the graduated
measuring cylinders of the 0 986 612 950 while
the engine is running (or the starter is cranking if
the engine does not start). By comparing the re-
turn quantity collected from the individual injec-
tors it is possible to identify a defective injector:
Robert Bosch GmbH
53 ml
45 ml
37 ml
29 ml
21 ml
13 ml
6.0 ml
4.0 ml
3.2 ml
2.4 ml
1.8 ml
Product description |
maximum allowed return quantity is 3 times as
much as the smallest return quantity measured.
The return quantity collected in the
0 986 612 950 does not need to match the return
quantity listed in the manufacturer's information
for the injectors. The scale provided is used for a
simple comparison of the returned quantity meas-
ured.
2.7.1 Example: Evaluation of the injector return
quantity with engine running
As an example, the following figure shows the re-
turn quantity from a 4-cylinder engine while run-
ning.
 3: Return quantity with engine running
Evaluation of the return quantity
• Injector 1 = 53 ml
• Injector 2 = 21 ml
• Injector 3 = 21 ml
• Injector 4 = 13 ml
The maximum allowed return quantity is 3 times
as much as the smallest return quantity meas-
ured: 13 ml x 3 = 39 ml.
Injector 1 has a return quantity of 53 ml and thus
exceeds the maximum allowed return quantity of
39 ml. Injector 1 is thus defective and must be re-
placed.
2.7.2 Example: Evaluation of the injector return
quantity with starter cranking (engine not
running)
As an example, the following figure shows the re-
turn quantity from a 4-cylinder engine when the
starter is cranking, but the engine is not running.
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0 986 612 950
0 986 629 001 | 2018-02-28