37
With low charge pressure, check:
–
for any damage to the turbocompressor
–
fuel filters, fuel feed pressure
–
charge pressure sensor
–
control rod travel, injection pump (see Testing in-
jection pump).
Example
At 0
°
C ambient temperature, the turbo pressure voltage
should be 3.7 V.
–
Go to 3.7 V on the vertical axis on the diagram.
–
Follow it horizontally to where it intersects the
vertical line for the ambient temperature (0
°
C).
–
The corrected voltage is read-off on the respective
curve in the diagram. In our example 3.5 V, which
corresponds to the voltage at 20
°
C.
6066
6065
- 20
- 10
+ 0
+ 10
+ 20
+ 30
+ 40
-
2
3
2.5
3.0
3.5
4.0
4.5
( V )
( C )
2.5
2.75
3.0
3.25
3.5
3.75
4.0 v
Fuel feed pressure
Special tools:
(999) 6065 Pressure gauge
6066 Nipple
968179
Banjo screw
Note: Before using the banjo screw, make sure it has
been decapitated to a length of 26 mm, otherwise it will
break the end of the thread insert in the pump connec-
tion.
Before measuring the feed pressure, run the engine at
high idle and then drop it to low idle when reading-off.
Read-off the pressure within one minute.
The fuel feed pressure must be min. 100 kPa (1.0 kp/
cm
2
).
A low feed pressure will have a negative effect on the
engine’s top output. In the event of complaints about
poor output, it would be well to check the feed pressure
under load (the same procedure as when checking the
charge pressure). Low fuel feed pressure can be caused
by a contaminated fuel filter, a faulty relief valve or
feed pump failure.
