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Engine Controls - On-Vehicle Adjustments BMW Z4 E85/E86

Adjustments ~855 words

ENGINE MECHANICAL

Before performing any on-vehicle adjustments to fuel or ignition systems, ensure engine mechanical condition is okay.

VALVE CLEARANCE

Note. Engines with the exemption of Motorsport (S54) engine use hydraulic valve lifters and valve adjustment is not required. For Motorsport engine valve adjustment, see 11 34 004 ADJUSTING VALVE CLEARANCE (S54) .

IGNITION TIMING

Ignition timing is electronically controlled and is not adjustable.

IDLE SPEED & MIXTURE

Note. Mixture adjustment is not a part of normal tune-up procedure and should not be performed unless mixture control unit is replaced or vehicle fails emissions testing.

HOT-FILM AIR MASS METER (HFM)

Air volume input signal is produced electronically by the HFM which uses a heated metal film in the airflow stream. ECM relay provides the operating voltage. As airflows through HFM, the film is cooled changing the resistance which affects current flow through the circuit. The sensor produces a 1-5 volt varying signal. Based on this change the ECM monitors and regulates the amount of injected fuel. If this input is defective, a fault code will be set and Malfunction Indicator Light (MIL) will be illuminated when OBD-II criteria is achieved. ECM will operate engine using throttle position and engine RPM inputs. HFM is non-adjustable.

IDLE SPEED

  1. Idle speed is controlled by an idle speed control valve. Ensure engine is at normal operating temperature, valve clearance is correct and all electrical accessories are off.
  2. Connect dwell/tachometer to engine. Ensure idle speed is within specification. See «IDLE SPEED & CO LEVEL»(/bmw/z4/e85e86-2002-2005/remont/adjustments/#engine-controls-on-vehicle-adjustments) table. If idle speed and CO level are not within specification, check idle speed control valve or intake manifold for air leaks. If problem is still present, check error memory. IDLE SPEED & CO LEVEL Application Idle RPM (1) (2) CO Level % 6-Cylinder & V8 650-750 .5 V12 (3) (3) (1) With A/C off and transmission in neutral. (2) Maximum specification, measured at exhaust manifold. See ON-VEHICLE ADJUSTMENTS article for additional information. (3) Information is not available.

IDLE MIXTURE & CO LEVEL

Note. This procedure does not apply to V12.

  1. Disconnect oxygen sensor connector. Remove bolt from exhaust manifold and install CO Test Connector (13-0-090) with Adapter (13-0-100) on exhaust manifold. Connect CO meter and check idle mixture. Ensure CO level is within specification. See «IDLE SPEED & CO LEVEL»(/bmw/z4/e85e86-2002-2005/remont/adjustments/#engine-controls-on-vehicle-adjustments) table.
  2. If CO level exceeds specification, check fuel injectors, fuel pressure and coolant temperature sensor. If CO level is less than specification, check idle speed control hoses and connections and check for air leaks. Reconnect oxygen sensor.

THROTTLE VALVE

The throttle valve plate is electronically operated to regulate intake air flow by the ECM. The purpose is for precision throttle operation, OBD compliant for fault monitoring, DSC and cruise control. This integrated electronic throttle reduces extra control modules, wiring, and sensors. Adjusting electronic throttles is not permitted, the throttle assembly must be replaced as a unit. The adaptation values must be cleared and adaptation procedure must be performed using the DISplus/GT1.

THROTTLE POSITION SENSOR

Accelerator pedal module provides two variable voltage signals to the ECM that represents accelerator pedal position and rate of movement. Dual Hall Sensors are integral in the accelerator pedal module. The ECM compares the 2 values for plausibility. The module contains internal springs to return the accelerator pedal to the rest position.

The ECM provides voltage (5 volts) and ground for the Hall sensors. As the accelerator pedal is moved from rest to full throttle, the sensors produce a variable voltage signal

  1. Hall sensor 1 (request) = 0.5 to 4.5 volts.
  2. Hall sensor 2 (plausibility) = 0.5 to 2.0 volts.

If the signals are not plausible, the ECM will use the lower of the two signals as the requested input. The throttle response will be slower and the maximum throttle response will be reduced. Throttle position sensor is not adjustable.

ACCELERATOR WITH ELECTRONIC ENGINE POWER CONTROL

Note. Following adjustment procedure is for Z3 models, but may apply to other models.

  1. To adjust first idling position, loosen hexagon nut on pedal value sensor. Create .011" (.3 mm) gap between accelerator pedal shaft and idle stop. Tighten hexagon nut on pedal value sensor. Support lever on pedal value sensor while tightening.
  2. To adjust full load position on manual transmission, actuate accelerator pedal as far as kickdown pressure point in pedal value sensor. In this position, adjust screw to bear on the accelerator pedal and lock it.
  3. On automatic transmission vehicles, operate accelerator pedal as far as kickdown pressure point in pedal value sensor. In this position, adjust screw to have .19" (5 mm) distance between knurled head screw and accelerator pedal. Lock stop screw.
  4. After adjusting, check pedal value sensor with BMW service tester or MoDiC. Switch ignition on. Move accelerator pedal to full load stop. Compare actual voltage value with the specified value. Move accelerator pedal to idling stop. Compare actual voltage value with the specified value. Correct adjustment if necessary. See «PEDAL VALUE SENSOR VOLTAGE SPECIFICATIONS»(/bmw/z4/e85e86-2002-2005/remont/adjustments/#engine-controls-on-vehicle-adjustments) table. PEDAL VALUE SENSOR VOLTAGE SPECIFICATIONS Application Specification Idle Speed 45-353 mV Full Throttle Automatic Transmission 3700-3950 mV Manual Transmission 3150-3450 mV

See also:
• IDLE SPEED & CO LEVEL