300CE (124.050) L6-3.0L (103.983) (1989)
Fuel Distributor: Technical Service Bulletins
Engine Shakes at Idle
07.3-90071
Engine Shakes at Idle
Engine 103 up to
7/90
Model Year 1990
Note:
If no roughness is noticed when checking the idle, no further tests are necessary.
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On engine 103 with automatic transmission, recognition of the selector lever position can be overridden;
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Using an approved digital ohmmeter, check continuity of wiring from connector socket 16 of CIS-E control unit (N3) to connector X26 (pin 10)
for models 124/126 or X26/3 (socket 1) for model 201.
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Remove violet wire (pin 10) from connector X26 or violet/white wire (socket 1) from connector X26/3 and permanently ground it. By doing so,
the idle speed with transmission engaged is raised by approx. 50 rpm.
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Further measures (replacing fuel distributor, injection valves) will not resolve problem and therefore should not be performed.
See: Electrical Wiring Diagrams, circuit: Electronic Engine Controls.
Ensure by measuring continuity that the cable to CIS-E control unit pin 16 was connected to ground and not the cable from ignition starter switch (S2/1),
since it could otherwise result in a short circuit.