Fuel Injection - Motronic M 1.1 Description: Overview
GROUP 12Engine
Electrical
Bulletin Number
12 01 86 (2051)
Montvale,NJ
April 1987
Technical Dept.
SUBJECT:
MOTRONIC M 1.1
ENGINES:
M20 (2.5i eta for 528e, starting in March 1987) and M30 (E32)
A new electronic fuel injection system, called the MOTRONIC M1.1, is being introduced by BMW. This system can be found on the M30 engines of the 735i (E 32) as well as on the M 20 engines of the 325i and 528e models.
Compared to the previous generation of MOTRONIC, this latest generation has a wider "adaptive" range, i.e., the ability to run the engine in a so called emergency mode, thus allowing the driver to continue operating the vehicle if certain engine components fail. This wider adaptive range allows the MOTRONIC 1.1 to compensate for wear or other negative factors (such as air leaks, for example). It keeps emissions within specifications and optimizes driveability. The MOTRONIC 1.1 also has the ability to recognize when certain pre-selected inputs or outputs have incorrect values (i.e. values outside their parameters) and thus identifies these pre-selected faults when they occur, even intermittently.
Once a fault is identified it is stored in the memory of the Control Unit, to be later displayed on the BMW Service Tester. The system then automatically substitutes a fixed replacement value for the incorrect value inside the Control Unit, thereby allowing the engine to continue running in the so called emergency mode.
Certain malfunctions affecting exhaust emissions will be stored in memory as well and cause the "CHECK ENGINE" light in the instrument cluster to be illuminated.
Other new features are the Adaptive Idle Speed and Purge Control Systems as well as the Half Sequential Fuel Injection System.
The non-adjustable M1.1 system with its enlarged adaptive, i.e. self learning abilities, compensates for changed conditions to a far larger extent than the previous Motronic systems.
IN CASE OF IDLE/IDLE MIXTURE PROBLEMS, NO ATTEMPTS SHOULD BE MADE TO CHANGE IDLE SPEED/IDLE MIXTURE BY TRYING TO MANIPULATE THE TAMPER PROOF BYPASS SCREW IN THE AIRFLOW METER OR TO ALTER THE THROTTLE BUTTERFLY PLATE POSITION.
In case of problems, verify that all components which might influence idle/idle mixture, work properly according to specifications and troubleshooting procedures. If all the applicable components work properly and there are no other influences (such as unmetered air, improperly adjusted intake/exhaust valves, extremely diluted oil etc.) and idle/idle mixture problems should persist, the idle control valve and/or Motronic Control Unit must be replaced.