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Fuel System - Electronic Control 944 S/944 S2
d) Ignition timing test
Ignition timing is checked with the engine at
operating temperature.
Ignition timing and engine speed can be
read direct in the "actual value" menu with a
9288 System Tester.
Test value: (944 S + 944 S2)
At 840 +- 40 rpm 10° +- 3°
e) Activation of high tension end
(if ignition sparks are not triggered)
Ignition triggering signal can be simulated for
fast troubleshooting of the ignition end. This
requires connecting the oscilloscope term. 4
tester lead on the ignition lead betw. ignition
cail and high tension distributor (term. 4).
Disconnect DME control unit plug.
Turn on ignition.
If battery voltage is new supplied
intermittently to terminal 1 of the control unit
with help of a test lead (e.g. control unit plug
term. 18), a high tension peak must be
displayed on the oscilloscope each time
(ignition triggering).
If there is no signal, check:
-
Power supply to ignition final stage and
ignition coil.
-
Ground connection for ignition final stage
(ground point on left front side member).
- Plug connections on ignition final stage,
ignition coil and high tension distributor.
-
Components responsible for high tension
(for example: ignition coil, ignition leads,
spark plug connectors, etc.).
- Power flow in lead between control unit
plug and ignition final stage term. 5.
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DME - Diagnosing/Troubleshooting
Printed In Germany - XXI, 1989