Repair Procedure For Units With A Code of 341 or Earlier

B. Motronic Control units with a Bosch date code of 341 or earlier (lower). Installed in vehicies from 9/81 to approximately 2/83.

1. Disconnect the idle control unit plug. Unsnap the cover on the plug and remove the brown/red wire from pin # 11. Insulate the wire connector and tape back against the wiring harness. Reconnect plug to the idle control unit.

2. Remove the spark plugs. Install a set of WR9LS spark plugs (BMW Part Number 12 12 1 279 599). Set plug gap to 0.7 mm + 0.1 mm (.032") before installing.



3. Obtain a 560 ohm, 1/2 watt, "Gold Band" metal film resistor; available from BMW under part no. 88 88 5 000 359.



4. Cut the two pigtail ends of the resistor as shown (drawing not to scale) leaving approximately 10 mm (3/8") of the wire end attached to the resistor.



5. Remove the connector (white) from the coolant temperature sensor (NTC) in the thermostat housing. Cut open (lengthwise) the grey insulating sleeve from the rubber boot back about two inches. Cut the brown/red wire and proceed as follows:

a) strip back 1/2" of insulation from each end of the cut brown/red wire.

b) slide one end of an insulating sleeve of "shrink-fit" tubing over one wire.

c) wrap one wire end around each end of the resistor and solder.



d) slide the "shrink-fit" tubing over the resistor and wires.

e) insert the brown/red wire plus resistor back into the opened section of the grey insulating sleeve.

f) tape around the grey insulating sleeve, ensuring an overlap on the two ends of the opening.
6. Reconnect the "white" plug to the coolant temperature sensor (NTC).

7. Test drive.