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.

- On engine 103 with automatic transmission, recognition of the selector lever position can be overridden;

- 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.

- 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.

- 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.