Bosch MOT 240 Operating Instructions Manual page 71

4.1.3 Subprogram cylinder balance/dynamic compression
(skipped only when diesel adapted is plugged in)
Remarks:
During the cylinder balance/dynamic compression the ignition
system is short-circuited on the primary side. The result in the
case of motor engines is that "error" is set in the error memory of
the electronic control unit. After the test, the error memory must
be erased as specified by the vehicle manufacturer.
Measurement of oil temperature and rpm. After starting the test
step:
Display of drop in speed in per cent and in rpm, each referred to
the speed when the "Start" key was pressed (softkey F5 or F6),
and the current speed.
Oscillogram: secondary voltage
Range: 25 kV/720° or 360° crankshaft (°CS)
F4: Pressing this key initiates the automatic execution of the
dynamic compression measurement based on starter
current. Comply with appropriate instructions on the status
line.
Steps:
- Engine OFF
- Press hardkey "Ignition short-circuit" K (continued short
circuit)
- Actuate starter until engine starts (continued short circuit
is automatically cancelled).
- Read results of measurement.
Remarks:
If engines have different ignition intervals and EFS without
camshaft sensor (with crankshaft sensor), it is impossible
to conduct the dynamic compression measurement.
F5: Pressing this key initiates the automatic cylinder balance
(Start key) with ∆ HC measurement - only in conjunction
with exhaust gas testers ETT 8.21 to 8.41 or ETT 8.5x/
8.6x /8.7x which are ready to operate.
When the German AU exhaust gas testers ETT 8.41/8.61
are used, it may be necessary to conduct a test for leaks
before the measurement.
F6: Pressing this key initiates the automatic cylinder balance
(Start key) without ∆ HC measurement.
The cylinder balance with and without ∆ HC is performed auto-
matically. The results of the measurement are displayed on the
screen afterwards and can then be printed out together.
Press the hardkey "Return" O to abort the measurement.
Results of the automatic cylinder balance without ∆ HC*
Results of the dynamic compression measurement*
*Remarks:
The reference to the individual cylinders always refers to the
current firing order.
e.g.: firing order 1 - 3 - 4 - 2
Result: (Cyl.) 1 = cylinder 1
(Cyl.) 2 = cylinder 3
(Cyl.) 3 = cylinder 4
(Cyl.) 4 = cylinder 2
This also applies accordingly for the record printout.
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