Engine Controls - Remove/install/overhaul BMW Z3 E36

INTRODUCTION

Removal, overhaul and installation procedures are covered in this article. If component removal and installation is primarily an unbolt and bolt-on procedure, only a torque specification may be furnished.

Note. Removal and installation procedures are supplied for those models and/or engines with available information.

Direct Ignition System (DIS)

1. Ensure ignition is turned off before working on the ignition system. The engine will not start without a connected secondary circuit. When checking compression, remove Digital Motor Electronics (DME) Electronic Control Unit (ECU) relay. See «DME & FUEL PUMP RELAY LOCATION»(/bmw/z3/e36-1995-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul) .
2. Shielded capacitors may not be connected to terminal No. 1 of the ignition coil. Terminal No. 1 of the ignition coil may not be connected to ground or battery positive terminal, as this will damage ignition stages in DME control unit.
3. DO NOT connect DVOM or test light to terminal No. 1 of ignition coil while engine is running. High tension (350 volts) is present at coil terminal No. 4, secondary ignition leads, spark plugs and ignition coil terminal No. 1 to DME Electronic Control Unit (ECU).

Note. For location of DME master and fuel pump relays, see DME & FUEL PUMP RELAY LOCATION under FUEL SYSTEM PRESSURE RELEASE under FUEL SYSTEM.

Removal & Installation (4-Cylinder)

Remove engine cover. (Scheme 1) Remove screw securing sensor lead above radiator hoses. Remove sensor lead from clip holder and guide rail. Locate sensor on right side of crankshaft and remove bolt and sensor. To install, reverse removal procedure.

Removal & Installation (6-Cylinder)

Remove engine cover. (Scheme 1) Locate sensor connector near engine oil level dipstick. Remove screws and crankshaft pulley cover. Locate sensor on right side of crankshaft and remove bolt and sensor. To install, reverse removal procedure.

Removal & Installation (V8)

Remove engine cover. (Scheme 1) Locate sensor connector near front of engine. Locate sensor near front of crankshaft and remove sensor mounting bolt. Remove sensor from bracket. To install, reverse removal procedure.

Scheme 1

1. Disconnect both connectors on electrical lead duct. Cylinder identifying sensor and Digital Motor Electronics (DME) pulse sensor are located side by side on front left side of engine, identifying sensor being on top.
2. Remove screw securing sensor lead above radiator hoses. Remove sensor lead from clip holder. Remove sensor. To install, reverse removal procedure.

Locate sensor connector near engine oil level dipstick. Locate sensor on front left side of engine. Remove sensor bolt. Remove sensor. To install, reverse removal procedure.

Remove engine cover. (Scheme 1) Locate sensor on front of right cylinder head. Remove sensor. (Scheme 2) Disconnect connector located on top of engine at harness conduit.

Scheme 2

ENGINE CONTROL UNIT (ECU)

Note. Disconnect battery before removing Digital Motor Electronics (DME) ECU. Disconnecting battery will clear ECU Diagnostic Trouble Codes (DTCs). Retrieve DTCs before disconnecting battery. ECU stores certain basic driveability values. ECU also receives different input values, depending on engine condition, which are compared with stored values. ECU adaptive system compares input values with stored values. ECU replacement could cause poor engine performance before all values are adapted to engine condition. Before exchanging ECU, ensure engine is at normal operating temperature. Remove old ECU, install new ECU and operate vehicle at different RPMs.

Removal & Installation (Z3)

ECU is located in box in right rear of engine compartment. Remove ECU box cover. Disconnect electrical connector. Remove ECU. To install, reverse removal procedure.

Removal & Installation (3-Series)

ECU is located behind cover on firewall in right rear of engine compartment. On 4-cylinder vehicles, remove battery. On all vehicles, remove 4 ECU cover screws. (Scheme 3) Unlock electrical connector retainer. Disconnect electrical connector. Slide out ECU. (Scheme 4) To install, reverse removal procedure.

Scheme 3

Scheme 4

Removal & Installation (5-Series, 7-Series & 8-Series)

1. ECU is located in box in right rear corner of engine compartment. Open locking bracket on ECU box. Open filter housing cover. Unhook filter housing from hinges. Unhook retaining clip and pull filter housing upward. Remove filter housing.
2. Remove 4 ECU cover bolts. Disconnect ECU electrical connector. Remove ECU. To install, reverse removal procedure.

Scheme 5

Scheme 6

1. Remove engine cover. (Scheme 1) Disconnect ignition coil connector. Remove ignition coil nuts. Remove ignition coil(s). (Scheme 5)
2. To install, reverse removal procedure. Install ground strap. (Scheme 6) Ensure ignition coil common ground lead is attached to front of cylinder head, near engine lift bracket.

Remove engine cover. (Scheme 1) Disconnect wiring connectors from coil. Remove ignition coil nuts. Remove ignition coil(s). (Scheme 5) To install, reverse removal procedure.

Removal (4-Cylinder)

1. Remove engine cover. (Scheme 1) Remove harness conduit from injector rail. Remove upper intake manifold. Remove harness cover from lower intake manifold.
2. Mark knock sensor connectors for reassembly reference. Disconnect coolant hose to access knock sensors. Remove knock sensor(s) from engine.

Installation (4-Cylinder)

Clean knock sensor contact area. When tightening sensors, ensure sensor and wiring do not interfere or chafe on brackets or other components. Ensure sensors are plugged into correct connectors. To complete installation, reverse removal procedure.

Removal (6-Cylinder)

Remove engine cover. (Scheme 1) Mark knock sensor connectors for reassembly reference. Knock sensors connectors are located below idle speed controller. Disconnect connectors. Remove knock sensors, located on side of engine block.

Installation (6-Cylinder)

Clean knock sensor contact surface. When tightening knock sensors, ensure sensor and wiring do not interfere or chafe on brackets or other components. Ensure sensors are plugged into correct connectors. To complete installation, reverse removal procedure.

Scheme 7

1. Remove engine cover. (Scheme 1) Disconnect vacuum hoses to intake manifold and throttle body. Drain radiator and remove coolant expansion tank. Remove coolant manifold from rear of cylinder heads.
2. Disconnect fuel feed and fuel return lines at engine. Disconnect fuel lines and fuel tank vent line at engine carrier. Disconnect fuel line and wiring from top of fuel vapor canister.
3. Loosen hose clamps on idle speed controller and throttle body. Disconnect airflow sensor connector. Remove air cleaner housing/airflow sensor assembly. Raise and support vehicle. Disconnect oil level sensor connector. Disconnect and remove ignition coils.
4. Disconnect crankshaft position sensor and both knock sensor connectors. Disconnect intake air temperature sensor, idle speed potentiometer and idle speed controller connectors. Remove BMW engine diagnostic connector socket from bracket. Disconnect connector next to BMW diagnostic connector socket.
5. Remove bolt securing ignition coil ground wire (near engine lift bracket). Disconnect temperature gauge and temperature sensor connectors for DME (Black connector and White connector near engine lift bracket).
6. Completely disconnect throttle cable from engine. Remove intake manifold. Mark knock sensor connectors for reassembly reference. Remove knock sensor(s). (Scheme 7) To install, reverse removal procedure. Ensure knock sensors are connected to proper connectors.

FUEL SYSTEM

3-Series (E36)

Filter on firewall of vehicle: Remove cover from fuel filter. Disconnect fuel delivery line with special tool 13 3 010 before and after the fuel filter. Unfasten hose clips and remove fuel line from fuel filter.

Scheme 8

Unfasten screw and remove filter from bracket. Filter on underbody of vehicle: Unfasten screws and remove cover from fuel filter. Disconnect fuel inlet line at points (1) and (2) with special tool 13 3 010.

Scheme 9

Unfasten hose clips and remove fuel line from fuel filter. Fuel filter with quick release coupling. Push lock toward filter while pulling off fuel hose. Unfasten screw and remove filter from bracket.

Scheme 10

Installation: Check direction of flow (arrow). Arrow must point towards the injection valve strip.

Scheme 11

M52, M60, M62 & M73 (Except E36)

Switch off ignition. Unfasten screws on lower trim (1).

Scheme 12

Fold lower trim to one side.

Scheme 13

Disconnect fuel lines with special tool 13 3 010. Catch and dispose of escaping fuel.

Scheme 14

Illustrated here without lower trim: Unfasten hose clips. Replace hose clips.

Scheme 15

Unfasten screws. Remove fuel filter. Replace fuel filter.

Scheme 16

Installation: Note installation direction of fuel filter. Direction of flow is marked with an arrow on the fuel filter. The arrow points towards the injector strip.

Scheme 17

The embossed designation "OUT " on outlet of fuel filter must be mounted facing the injector strip.

Scheme 18

FUEL SYSTEM PRESSURE RELEASE

Fuel system pressure release procedure not available from manufacturer. It may be possible to remove fuel pump relay, start engine, and run engine until fuel pressure drops (engine stalls). See DME & FUEL PUMP RELAY LOCATION .

DME & FUEL PUMP RELAY LOCATION

Scheme 19

Scheme 20

Turn ignition off. Unfasten clips between mass airflow sensor and air filter housing. Remove hose clamp. Remove mass airflow sensor. Disconnect electrical connector. To install, reverse removal procedure.

1. Turn coupling and disconnect mass airflow sensor connector. Loosen hose clamp and pull off bellows.
2. Loosen screws or open fasteners at air cleaner assembly. Remove mass airflow sensor and bellows. (Scheme 21) To install, reverse removal procedure. Ensure mass airflow sensor grille is not damaged during installation.

Loosen hose clamp and pull off air intake hose. Unclip and remove upper portion of air cleaner housing. Remove mass airflow sensor mounting bolts. To install, reverse removal procedure.

Scheme 21

Removal & Installation (Z3 & 3-Series)

1. Fuel pump is integral with right fuel level sensor. Siphon out as much fuel as possible from fuel tank. Remove passenger seat cushion (Z3) or rear seat cushion (all others). Remove or cut insulation mat along perforated line and fold open.
2. Remove fuel pump access cover (if equipped). Press Green unlocking ring and detach fuel delivery hose (M3), or mark fuel hoses for installation reference and disconnect hoses (all others). Disconnect electrical connectors. Loosen screw cap with Special Tool (161020). Remove screw cap and sealing ring. (Scheme 22) Remove fuel pump assembly.

Installation

Ensure height sensor is pressed onto inside face of fuel baffle. Rotate screen and float into fuel tank. Ensure marker rib on fuel pump unit aligns with mark on fuel tank. Install new sealing ring. Tighten screw cap. To complete installation, reverse removal procedure.

Scheme 22

Removal (5-Series)

1. Siphon out as much fuel as possible from fuel tank. Remove rear seat. Remove or cut insulation mat along perforated line and fold open. Remove rubber grommet. Remove 3 fuel pump/sending unit cover screws. Disconnect electrical connectors.
2. Remove hose clamp. Disconnect hose. Loosen screw cap with Special Tool (161020 ). Lift out fuel level sensor. Compress retaining hook on fuel pump (Black housing). Remove fuel pump from fuel baffle (White housing). Disconnect fuel pump electrical connectors. Remove hose clamp and carefully remove spiral hose. Remove fuel pump.

1. To prevent torsional stress, align spiral hose and cable between fuel level sensor and fuel pump. (Scheme 23) Install unit in fuel tank, ensuring both retaining hooks are aligned.
2. Ensure "O" ring is correctly aligned on intake neck. Tighten screw cap until notch can be heard and felt to engage in toothed section on tank. To complete installation, reverse removal procedure.

Removal (7-Series)

1. Siphon out as much fuel as possible from fuel tank. Remove rear seat. Remove or cut insulation mat along perforated line and fold open. Remove rubber grommet. (Scheme 24) Remove fuel pump/sending unit cover. Disconnect electrical connector.
2. Disconnect fuel line. (Scheme 25) Remove 8 lid nuts. Lift up lid as far as possible and swing it upward. Compress retaining hook on fuel pump Black housing. Remove fuel pump from fuel baffle White housing. Remove fuel pump and sender. (Scheme 26) Remove fuel pump from sender. Remove hose clamp and carefully remove spiral hose. Remove fuel pump.

Scheme 23

Scheme 24

Scheme 25

Scheme 26

Scheme 27

1. To prevent torsional stress, align connector hose and cable between lid and fuel pump. (Scheme 27) Install unit in fuel tank, ensuring both retaining hooks are aligned.
2. Ensure "O" ring is correctly aligned on intake neck. Install lid and tighten 8 screws in a crosswise pattern. To complete installation, reverse removal procedure.

Removal & Installation (4-Cylinder; Early With Fuel Rail Mounted Regulator)

Remove engine front brace. Locate fuel pressure regulator on end of fuel rail. (Scheme 28) Pull off fuel pressure regulator vacuum hose. Remove bolt from clamp securing fuel pressure regulator. Pull out fuel pressure regulator. To install, reverse removal procedure.

Scheme 28

Removal & Installation (4 & 6-Cylinder With Fuel Pressure Regulator Mounted Under Left Side Of Vehicle)

Fuel pressure regulator is located behind a cover under vehicle, under driver's seat area. Remove 4 fuel pressure regulator cover bolts. Disconnect vacuum hose. Remove locking bracket. Remove fuel pressure regulator.

1. Fuel pressure regulator is located at rear of intake manifold. Remove engine cover. (Scheme 1) Remove coolant expansion tank and BMW diagnostic connector (if necessary). Disconnect vacuum hose from pressure regulator. Remove circlip and pull pressure regulator out of fuel rail.
2. To install, reverse removal procedure. Replace "O" rings on regulator and lubricate with petroleum jelly. Install regulator in fuel rail. Compress circlip and engage tabs of circlip into fuel rail.

1. Remove engine cover. (Scheme 1) Pull off air duct hose and remove upper section of intake manifold collector. Remove engine front brace and rear brace.
2. Locate pre-heater assembly (if equipped) directly under throttle body and loosen pre-heater holder until bearing surface of pre-heater comes in contact with throttle valve.
3. Remove 9 intake manifold bolts. Lift upper section of intake manifold and pull hose off fuel pressure regulator. Pull connector plate off fuel injectors and remove clamp.
4. Remove 2 bolts, fuel rail and fuel injectors. Remove retainer from top of fuel injector. (Scheme 29) Remove fuel injector(s). To install, reverse removal procedure. Coat injector "O" rings with petroleum jelly.

Scheme 29

1. On 3-series, it may be necessary to remove ECU cover from right side of firewall. See «ENGINE CONTROL UNIT (ECU)»(/bmw/z3/e36-1995-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul__engine-control-unit-ecu). Unclip plastic clips along top edge of engine compartment firewall. Remove screws and wiring harness duct along engine compartment firewall. (Scheme 30)
2. On all models, remove engine cover. (Scheme 1) Loosen hose clamp and disconnect fuel supply hose from fuel rail. Remove 2 bolts and pull connector plate off fuel injectors. (Scheme 31) Remove 4 bolts and disconnect fuel rail. Pull up on fuel rail and injectors.
3. Remove retainer from top of fuel injector. (Scheme 29) Remove fuel injector(s). To install, reverse removal procedure. Coat injector "O" rings with petroleum jelly.

Scheme 30

Scheme 31

1. Release fuel system pressure. See «FUEL SYSTEM PRESSURE RELEASE»(/bmw/z3/e36-1995-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul__fuel-system-pressure-release). Remove engine cover. (Scheme 1) Disconnect throttle cable at throttle body. Disconnect ignition coils and fuel injectors.
2. Disconnect fuel lines from fuel rail. Remove fuel rail mounting screws and pull off fuel rail with injectors. Remove retainer from top of fuel injector. (Scheme 29) Remove fuel injector(s). To install, reverse removal procedure. Coat injector "O" rings with petroleum jelly.

Locate idle speed control valve at rear of intake manifold, just below last runner. (Scheme 32) Disconnect idle speed control valve electrical connector. Remove 2 nuts, pull out valve and at the same time disconnect hoses. To install, reverse removal procedure. Ensure new idle speed control valve clicks with ignition on.

Remove air filter housing. Remove throttle valve extension. Disconnect dip stick guide tube. Disconnect idle speed control valve electrical connector. Remove 2 bolts. Remove idle speed control valve. (Scheme 33) Remove gasket and rubber clip. To install, reverse removal procedure.

Remove engine cover. (Scheme 1) Disconnect idle speed control valve electrical connector. Remove top of air cleaner. Remove idle speed control valve mounting strap. Pull actuator from throttle body. To install, reverse removal procedure.

Scheme 32

Scheme 33

Disconnect temperature sensor electrical connector. Press locking button and unclip temperature sensor from intake air manifold. To install, reverse removal procedure.

Disconnect temperature sensor electrical connector. (Scheme 34) Press locking button and unclip temperature sensor. To install, reverse removal procedure.

Remove throttle body. See THROTTLE BODY . Disconnect intake air temperature sensor electrical connector. Press locking button and unclip temperature sensor from intake air manifold. To install, reverse removal procedure.

Scheme 34

Locate oxygen sensor connector below battery console and remove from clip holder. Pull off cover and remove oxygen sensor. To install, reverse removal procedure. Coat threads with anti-seize compound and install. Tighten oxygen sensor to 41 ft. lbs. (55 N.m).

Locate oxygen sensor connector on transmission carrier and remove from clip holder. Remove oxygen sensor. To install, reverse removal procedure. Coat threads with anti-seize compound and install. Tighten oxygen sensor to 41 ft. lbs. (55 N.m).

Information is not available from manufacturer.

Disconnect accelerator and cruise control cables from throttle body. (Scheme 35) Loosen throttle body air intake duct hose clamps and remove hoses. Disconnect throttle position switch connector and vacuum hoses. Remove 4 nuts, throttle body and gasket. To install, reverse removal procedure.

1. Remove mass airflow sensor. See «MASS AIRFLOW SENSOR»(/bmw/z3/e36-1995-2000/remont/removal-installation/#engine-controls-removeinstalloverhaul). Disconnect accelerator and cruise control cables from throttle body.
2. Loosen hose clamps and remove hoses attached to bottom of throttle body. Disconnect throttle position switch connector. Remove 4 bolts, throttle body and gasket. (Scheme 36) To install, reverse removal procedure.

Scheme 35

Scheme 36

Scheme 37

1. Remove engine cover. (Scheme 1) Disconnect mass airflow sensor, idle speed control actuator and throttle position sensor connectors. Remove top of air cleaner housing.
2. Disconnect throttle cable, hoses and idle speed control actuator from throttle body. Remove 6 throttle body bolts. (Scheme 37) Remove throttle body. To install, reverse removal procedure.

TORQUE SPECIFICATIONS

TORQUE SPECIFICATIONS

See also:
• DME & FUEL PUMP RELAY LOCATION
• ENGINE CONTROL UNIT (ECU)
• FUEL SYSTEM PRESSURE RELEASE