AutoZone 1986 Mazda 323 1.6L MFI SOHC 4cyl | Repair Guides | Fuel System | Fuel Injection System | Throttle Body | AutoZone.com

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    1986 Mazda 323 1.6L MFI SOHC 4cyl

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    BMW 318/325/M3/525/535/M5 1989-1993 Repair Information

    Throttle Body

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    The throttle body contains the throttle plates which controls the amount of air flowing into the engine. The throttle plate is connected to the accelerator pedal via a cable on all models except the 5 Series with traction control. The 5 Series cars that have traction control have a system called EML, translated into English is Electronic Motor Load regulation.

    EML is a system that controls the throttle not by cable, but by an electric servo motor. A sensor on the accelerator pedal feeds information about throttle position to the EML controller. The EML controller tells the servo motor on the throttle body how far to open the throttle plate. Because of the electronic control, there is no need for a separate cruise control actuator, for a transmission control cable or for a throttle cable. The only connection to the throttle body is a multi-pin electrical connector.


    CAUTION
    When ever work is performed on an EML component, such as the throttle body, the external safety check must be made. This is to make sure that the electronic throttle system is working properly. If the electronic throttle system is not working properly, the car may behave erratically causing personal injury or death.

    The procedure to perform the external safety path check requires a special BMW tool 12 7 010 or equivalent. Do not attempt any repairs on an EML related part without having access to the tool.

    REMOVAL & INSTALLATION



    M20, M30, M42 and M50 Engines

    See Figures 1 and 2



    Click image to see an enlarged view

    Fig. Fig. 1: Nuts 1 through 4 retain the throttle body-M42 engine



    Click image to see an enlarged view

    Fig. Fig. 2: Nuts 1 through 4 retain the throttle body-M50 engine

    1. On the M20 engine drain the coolant to below the level of the throttle body.
    2.  
    3. Turn the ignition switch to the OFF position.
    4.  
    5. Remove the intake air duct from the throttle body. If equipped with EML, remove the multi-pin connector.
    6.  
    7. Disconnect the throttle cable, the transmission cable and the cruise control cable. Mark and disconnect the vacuum lines and the air hoses. Move the idle speed control valve out of the way. Disconnect the coolant hoses on the M20 engine.
    8.  
    9. Remove the mounting nuts and remove the throttle body.
    10.  

    To install:
    1. Clean the mating surfaces of the throttle body and the intake manifold. Install a new gasket and the throttle body. Torque the mounting nuts to 6.5-8.0 ft. lbs. (9-11 Nm).
    2.  
    3. Connect the hoses, vacuum lines and air hoses to the throttle body. Replace the idle speed control valve.
    4.  
    5. Connect the throttle cables or EML connector. Install the intake air duct.
    6.  

    S14 Engine
    1. Turn the ignition switch to the OFF position.
    2.  
    3. Remove the cap nuts holding the intake manifold to the throttle bodies. Disconnect the throttle cable and the air hoses. The crankcase breather hose will have to be cut off. Remove the intake manifold.
    4.  
    5. Disconnect the harness from the throttle switch. Remove the fuel injector electrical plug plate from the injectors.
    6.  
    7. Remove the vacuum hose from the fuel pressure regulator. Remove the 2 mounting bolts and remove the fuel rail complete with the fuel injectors.
    8.  
    9. Disconnect the nut holding the throttle linkage. Remove the Torx nuts holding the throttle bodies to the cylinder head. Remove the throttle bodies.
    10.  
    11. Separate the throttle bodies if necessary.
    12.  

    The throttle shaft is supported by needle bearings. Do not draw the shaft through the bearings without making sure the shaft is clean. Dirt will cause damage the bearings and the shaft. Do not use any tools on the shaft that could damage the surface of the shaft. Do not disturb any of the adjustments on the throttle bodies. The settings are optimized at the factory and marked with paint dots.

    To install:
    1. If any components on the throttle bodies or linkage have been disturbed, they will have to be adjusted for proper operation.
    2.  
    3. The throttle body gaskets may be reused if there is no damage to the ridge around the gasket opening. Use a thin bead of silicon sealer around the opening ridge. Replace the gasket if there is any damage.
    4.  
    5. Attach the throttle bodies and check the condition of the connecting pipe O-ring for damage. Replace if necessary.
    6.  
    7. Install the throttle bodies to the cylinder head with the new or used gasket. Torque the mounting nuts to 6.5-8.0 ft. lbs. (9-11 Nm).
    8.  
    9. Connect the throttle linkage with a new locknut. Replace the fuel injectors and fuel rail. Torque the mounting nuts to 6.5-8.0 ft. lbs. (9-11 Nm).
    10.  
    11. Install the fuel injector electrical plug plate and the throttle switch connector.
    12.  
    13. Check the intake manifold O-rings and replace if necessary. Install a new crankcase breather hose. Install the intake manifold, air hoses and throttle cable.
    14.  

    S38 Engine
    1. Disconnect the negative battery terminal. Disconnect the throttle cable. Remove the air intake hose. Remove the screws on each throttle valve assembly.
    2.  
    3. Disconnect the hose for the idle speed control, the venting hose and the oil return hose. Remove the nuts for the oil trap and pull off the air intake assembly.
    4.  
    5. Pull off the plug plate from the fuel injectors. Disconnect the fuel lines from the fuel rail. Pull of the intermediate plug for the idle speed control. Remove the fuel rail with the fuel injectors.
    6.  
    7. Disconnect the vacuum hoses after noting the routing. Remove the 6 10mm nuts and the 9 13mm nuts. Remove the shaft connection nut. Disconnect the throttle linkage and remove the throttle bodies.
    8.  
    9. Separate the throttle bodies by disconnecting the connecting pipes. Check the O-rings on the pipe. Clean the throttle shafts before pulling out of the bores and do not use tools on the shaft or it may be damaged.
    10.  

    To install:
    1. Install the throttle bodies together using new O-rings on the connecting pipes. Install the throttle bodies on the engine using new gaskets. Tighten the 10mm nuts to 6.5-8.0 ft. lbs. (9-11 Nm) and the 13mm nuts to 14-17 ft. lbs. (20-24 Nm).
    2.  
    3. Route and connect the vacuum hoses. Install the shaft connection nut and the throttle linkage. Install the fuel rail and the fuel connections. Connect the intermediate plug and the injector plug plate.
    4.  
    5. Check the O-rings on the air intake assembly and attach the pins at the bottom of the assembly. Install the air intake assembly.
    6.  
    7. Connect the oil return hose, the idle speed hose and the venting hose. Install the air intake duct and install the screws at each throttle. Connect the negative battery terminal.
    8.  

    ADJUSTMENTS



    The only throttle body adjustments that can or should be done are on the S14 and S38 engines. The other engines are equipped with throttle bodies that need no adjustments. The S14 and S38 engine throttle body adjustments should be performed only if the throttle bodies were disassembled or damage occurred.

    Special tools needed for these procedures include feeler gauges, dial indicators, dial indicator mounts, and vernier calipers. The settings are very precise and require familiarity with the tools being used.

    Idle Speed Stop
    1. Loosen the idle speed adjustment stop lock nut and loosen the screw 1/10 of a turn in the counterclockwise direction.
    2.  
    3. Close the throttle plates and press the throttle lever against the stop screw. Tighten the nut.
    4.  
    5. Install a dial indicator on the throttle body with the tip on the deepest point of the throttle plate. Preload the tip and zero the dial.
    6.  
    7. Loosen the nut and turn in the screw to move the throttle plate 0.004-0.006 inch (0.10-0.15mm). This will be approximately 1/10 of a turn. Tighten the locknut and mark with a paint dot.
    8.  

    Axial Clearance
    1. The measurements used in this procedure are based on the ambient temperature being 68°F. (20°C.).
    2.  
    3. Close the throttle plates. Check that the throttles move easily.
    4.  
    5. Check that a 0.008 inch (0.2mm) feeler gauge can fit between throttle body housing and the snapring or throttle lever.
    6.  
    7. Check for damage or warpage if the feeler gauge does not fit.
    8.  

    Full Load Stop
    1. Open the throttle plates to the full open position.
    2.  
    3. Measure the distance from the top edge of the throttle plate to the top of the throttle bore. The measurement should be 0.854 inch (21.7mm).
    4.  
    5. If the measurement is not correct, loosen the locknut on the screw mounted in the middle of each throttle housing, between the throttle bores. Move the screw to achieve the correct measurement. Do not change the length of the throttle linkages.
    6.  
    7. If there is any deviation from the measurement, it should be evenly shared by each of the throttle housing.
    8.  

    Throttle Lever
    S14 ENGINE
    1. The throttle lever pushrods must be check and adjusted for length. On the S14 engine, the pushrod for cylinders 1 and 2 should be 3.937 inch (100mm) and the pushrod for cylinders 3 and 4 should be 3.822-3.854 inch (97.1-97.9mm).
    2.  
    3. Install the pushrods and align the levers. Loosen and move the clamps to obtain alignment.
    4.  
    5. Install a dial indicator on cylinder 3 and 4 throttle lever. Adjust the cylinders 1 and 2 pushrod until movement is noted on the dial indicator. The throttle levers are adjusted when they evenly hit the idle speed stop.
    6.  

    S38 ENGINE
    1. The throttle lever pushrods must be check and adjusted for length. On the S38 engine, the pushrods for cylinder pairs 1 and 2, 3 and 4 should be 3.858 inch (98mm) and the pushrod for cylinders 5 and 6 should be 3.822-3.854 inch (97.1-97.9mm).
    2.  
    3. Install the pushrods and align the levers. Loosen and move the clamps to obtain alignment.
    4.  
    5. Install a dial indicator on cylinder 5 and 6 throttle lever. Evenly adjust the cylinder 1 and 2, and 3 and 4 pushrods until movement is noted on the dial indicator. The throttle levers are adjusted when they evenly hit the idle speed stop.
    6.  

    CHECKING EXTERNAL SAFETY PATH



    This procedure must be completed anytime a component of the EML throttle by wire system is removed or disconnected. It requires tool 12 7 010 or equivalent. Do not work on any EML component without having access to this tool.

    1. Turn the ignition switch to OFF . Unplug the EML connector. The EML connector is grouped with the DME engine connectors. The EML connector is next to the engine diagnostic connector, centered in the group of 3 circular connectors.
    2.  
    3. Install the EML testing adapter 12 7 010 or equivalent to the EML connector inline. Make sure all connections are tight.
    4.  
    5. Turn the knob on the tester to the left position and start the engine. Adjust the engine speed to 2500 rpm with the tester knob.
    6.  
    7. Depress the brake pedal. The engine speed should drop immediately due to the overrun shutoff provision.
    8.  
    9. If the engine speed does not drop immediately, check the EML system for faults. If the speed does drop immediately, the EML external safety path is functioning.
    10.  
    11. Shut off the engine and remove the tester.
    12.  

     
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