Fuel - Inconsistent Engine Idle Speed

86BMW05

GROUP 13 Fuel System
Bulletin Number 13 14 86 (1214) Page 1 of 1
Montvale, NJ July 1986 Technical Dept.
SUBJECT: Procedure for checking/adjusting idle speed on vehicles with idle speed control integrated into Motronic Control Unit

MODELS: 535i, 635CSi, 735i with EH Transmissions

Complaint: Inconsistent engine idle speed.

Cause: Insufficient air flow (in throttle butterfly housing).

Correction: Correct basic adjustment of throttle butterfly.

Procedure: 1. Check that the following conditions are met:
^ All normal engine adjustments are correct.
^ The engine is fully warm (i.e. oil temperature minimum of 140~/60~C).
^ All electrical consumers switched OFF, particularly the Air Conditioning (A/C).

2. Connect universal adapter (P/N 81 12 9 425 091) with adapter cable for periphery check, 35 pin (P/N 81 12 9 425 092) and control unit adapter (P/N 81 12 9 425 093) between Motronic Control Unit and Engine Harness.

3. Bridge pins 2 and 3 with pin 5.

4. Start engine and check if idle speed is within specifications: 800 +/- 50 RPM. IF NOT, PROCEED TO step 5.

5. Adjust throttle lever stop to achieve an idle speed of 780 - 800 RPM.

6. Remove universal adapter.

7. Check closed throttle switch and potentiometer per Repair Manual Operation No. 13 63 544 and adjust, if required.

Warranty
Status: Idle speed adjustment is a maintenance item and is not reimbursable under warranty.