AutoZone 1999 Mercedes Benz SL500 5.0L SFI 8cyl | Repair Guides | Emission Controls | Emission Controls | Secondary Air Injection (air) System | AutoZone.com

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    GM Camaro/Firebird 1993-1998 Repair Guide

    Secondary Air Injection (AIR) System

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    OPERATION



    See Figures 1, 2, 3 and 4

    The Secondary Air Injection (AIR) system, used on 3.4L and 5.7L engines, helps reduce Hydrocarbon (HC), Carbon Monoxide (CO), and Oxides of Nitrogen (NO x ) exhaust emissions. It also causes the oxidation catalytic converter to heat quickly which allows the conversion of exhaust gases to occur sooner.



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    Fig. Fig. 1: Schematic of the secondary Air Injection (AIR) system-3.4L engine



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    Fig. Fig. 2: Secondary Air Injection system air flow schematic-1995 5.7L engine shown

    The AIR pump is mounted to either the lower left front of the engine or under the ABS hydraulic modulator and supplies the air for the system. The electric air pump pressurizes air from the air cleaner and pumps it to the check valves located near the exhaust manifolds. By providing the ground, the PCM completes the circuit which energizes the pump relay and turns both the pump and the integral stop valve on. When the PCM turns the pump off, it also de-energizes the integral stop valve solenoid so no air is directed into the exhaust ports.



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    Fig. Fig. 3: Exploded view of a typical secondary AIR system



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    Fig. Fig. 4: Secondary AIR system hose routing-3.4L engine shown, other engines similar

    Anytime the engine coolant temperature is above 59°F (15°C) after startup, the PCM will enable this system and operate it for a maximum of about 3 to 4 minutes or until the system enters "Closed Loop''. The following are some of the conditions which will cause the PCM to disable the system:



    When engine rpm is below 400 rpm
     
    Under heavy acceleration
     
    The catalytic converter is overheating
     
    Engine coolant temperature is less than 59°F (15°C)
     
    Fuel control is not within normal ranges
     
    Engine rpm is above 2825 rpm (5.7L) or 3200 rpm (3.4L) for more than 5 seconds
     
    When the PCM detects a problem in the system and sets a diagnostic trouble code (DTC)
     

    SERVICE



    AIR Pump
    1. Inspect the hoses, tubes and all connections for possible leaks and proper routing.
    2.  
    3. Check for air flow to the exhaust ports.
    4.  
    5. Check the pump for proper mounting.
    6.  

    Hoses and Pipes
    1. Check for deterioration or holes in the hoses and pipes.
    2.  
    3. Make sure all connections and clamps are tight.
    4.  
    5. Check for proper routing as interference may cause premature wear.
    6.  

    Check Valve
    1. Blow through the check valve towards the cylinder head, then attempt to suck back through the valve (or blow through the other side).
    2.  
    3. Flow should only be in one direction (towards the exhaust manifold). Replace as necessary.
    4.  

    REMOVAL & INSTALLATION




    CAUTION
    Make sure the engine is cool before attempting to service the secondary AIR system to avoid being severely burned.

    AIR Pump
    EXCEPT 1998 5.7L ENGINE

    See Figures 5, 6, 7 and 8

    1. Disconnect the negative battery cable.
    2.  
    3. For the 3.4L engine, raise and safely support the vehicle.
    4.  
    5. Detach the electrical connector from the AIR pump.
    6.  
    7. Disconnect the outlet and inlet hoses.
    8.  
    9. Remove the three pump mounting bolts, then remove the AIR pump from the vehicle.
    10.  



    Click image to see an enlarged view

    Fig. Fig. 5: On the 3.4L engine, then AIR pump is mounted under the ABS modulator, on the front of the engine



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    Fig. Fig. 6: Location of the AIR pump-1993 5.7L engine shown



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    Fig. Fig. 7: Disconnect the outlet (5) and inlet (4) hoses from the AIR pump (3)-1996 5.7L engine shown



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    Fig. Fig. 8: Exploded view of the AIR pump-1995 5.7L engine shown

    To install:
    1. Position the AIR pump and secure with the mounting bolts. Tighten the bolts to 9 ft. lbs. (12 Nm) on the 3.4L engine and to 50 in. lbs. (6 Nm) on the 5.7L (VIN P) engine.
    2.  
    3. Connect the inlet and outlet hoses.
    4.  
    5. Attach the electrical connector to the AIR pump.
    6.  
    7. For the 3.4L engine, carefully lower the vehicle.
    8.  
    9. Connect the negative battery cable.
    10.  

    1998 5.7L ENGINE

    See Figures 9, 10 and 11

    1. Disconnect the negative battery cable.
    2.  
    3. Raise and safely support the vehicle.
    4.  
    5. Remove the left hand lower close-out panel.
    6.  



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    Fig. Fig. 9: Remove the left side lower close-out panel-1998 5.7L engine

    1. Disconnect the hoses from the AIR pump.
    2.  
    3. Detach the electrical connector from the AIR pump.
    4.  
    5. Detach the electrical connector from the AIR bleed valve solenoid.
    6.  



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    Fig. Fig. 10: Disconnect the hoses and detach the electrical connectors from the AIR pump

    1. Remove the three AIR pump mounting bolts from the bracket, then remove the AIR pump from the vehicle.
    2.  



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    Fig. Fig. 11: Unfasten the 3 retaining bolts, then remove the AIR pump from the vehicle

    1. Position the AIR pump and install the mounting bolts. Tighten the bolts to 80 inch lbs. (9 Nm).
    2.  
    3. Attach the electrical connectors to the AIR bleed solenoid and AIR pump.
    4.  
    5. Connect the hoses to the AIR pump.
    6.  
    7. Install the left hand side close-out panel.
    8.  
    9. Carefully lower the vehicle, connect the negative battery cable and check the AIR system for proper operation.
    10.  

    Air Check Valve

    See Figure 12

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the check valve clamp.
    4.  
    5. Disconnect the hose from the check valve.
    6.  
    7. Remove the left check valve pipe.
    8.  
    9. Unscrew the check valve from the AIR pipe.
    10.  



    Click image to see an enlarged view

    Fig. Fig. 12: AIR system pipes, hoses and check valves-1993-95 5.7L engine

    To install:
    1. Screw the check valve onto the pipe.
    2.  
    3. Tighten to 14 ft. lbs. (19 Nm) on the 3.4L engine and to 17 ft. lbs. (23 Nm) on the 5.7L engine.
    4.  
    5. Attach the AIR pipe to the exhaust manifold.
    6.  
    7. Fasten the AIR hose to the check valve.
    8.  
    9. Install the check valve clamp.
    10.  
    11. Connect the negative battery cable.
    12.  

    Air Check Valve/Pipes-Bank 1
    1996-97 5.7L ENGINES

    See Figure 13

    1. Disconnect the negative battery cable.
    2.  
    3. Loosen the check valve clamp.
    4.  
    5. Disconnect the AIR hose from the check valve.
    6.  
    7. Detach the left check valve pipe.
    8.  
    9. Unscrew the check valve from the AIR pipe.
    10.  



    Click image to see an enlarged view

    Fig. Fig. 13: Air check valve (3), and valve clamp (2) location-1996-97 5.7L engine

    1. Before replacing a check valve, test the valve for proper operation, as follows:
      1. Install a vacuum pump to the nipple side of the check valve, AIR pump side.
      2.  
      3. Pump the vacuum pump to 10 in. Hg and observe the gauge.
      4.  
      5. If the vacuum bleeds down to zero within 5 seconds, replace the check valve.
      6.  

    2.  

    To install:
    1. Screw the check valve onto the AIR pipe. Tighten the check valve to 17 ft. lbs. (23 Nm).
    2.  
    3. Attach the AIR pipe to the exhaust manifold.
    4.  
    5. Connect the air hose to the check valve.
    6.  
    7. Install the check valve clamp.
    8.  
    9. Connect the negative battery cable.
    10.  

    1998 5.7L ENGINES

    See Figure 14

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the check valve clamp.
    4.  
    5. Disconnect the AIR hoses from the check valve.
    6.  
    7. Unscrew the check valve from the AIR pipe.
    8.  
    9. Remove the left AIR pipe from the manifold.
    10.  



    Click image to see an enlarged view

    Fig. Fig. 14: Bank 1 AIR check valve mounting-1998 5.7L engine

    1. Before replacing a check valve, test the valve for proper operation, as follows:
      1. Install a vacuum pump to the nipple side of the check valve, AIR pump side.
      2.  
      3. Pump the vacuum pump to 10 in. Hg and observe the gauge.
      4.  
      5. If the vacuum bleeds down to zero within 5 seconds, replace the check valve.
      6.  

    2.  

    To install:
    1. Screw the check valve onto the AIR pipe and tighten to 17 ft. lbs. (23 Nm).
    2.  
    3. Connect the AIR pipe to the exhaust manifold and tighten to 15 ft. lbs. (20 Nm).
    4.  
    5. Install the AIR hose to the check valve, install the check valve clamp.
    6.  
    7. Connect the negative battery cable, then check the system for proper operation.
    8.  

    Air Check Valve/Pipes-Bank 2
    1996-97 5.7L ENGINES

    See Figure 15

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the clamps and the AIR hoses from the AIR system right pipe.
    4.  
    5. Remove the right check valve pipe.
    6.  
    7. Unscrew the check valve from the AIR pipe.
    8.  



    Click image to see an enlarged view

    Fig. Fig. 15: Location of the check valve (1), clamps (2) and AIR system right pipe (3)-1996-97 5.7L engine

    1. Before replacing a check valve, test the valve for proper operation, as follows:
      1. Install a vacuum pump to the nipple side of the check valve, AIR pump side.
      2.  
      3. Pump the vacuum pump to 10 in. Hg and observe the gauge.
      4.  
      5. If the vacuum bleeds down to zero within 5 seconds, replace the check valve.
      6.  

    2.  

    To install:
    1. Screw the check valve onto the AIR pipe.
    2.  
    3. Tighten the check valve to 17 ft. lbs. (23 Nm).
    4.  
    5. Connect the right AIR pipe to the exhaust manifold.
    6.  
    7. Install the hose and clamp to the check valve.
    8.  
    9. Connect the negative battery cable, then check the system for proper operation.
    10.  

    1998 5.7L ENGINES

    See Figure 16

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the clamps and AIR hoses from the AIR system right pipe.
    4.  
    5. Disconnect the AIR hose from the check valve.
    6.  
    7. Unscrew the check valve from the AIR pipe.
    8.  
    9. Remove the right AIR pipe from the manifold.
    10.  



    Click image to see an enlarged view

    Fig. Fig. 16: Bank 2 AIR check valve mounting-1998 5.7L engine

    1. Before replacing a check valve, test the valve for proper operation, as follows:
      1. Install a vacuum pump to the nipple side of the check valve, AIR pump side.
      2.  
      3. Pump the vacuum pump to 10 in. Hg and observe the gauge.
      4.  
      5. If the vacuum bleeds down to zero within 5 seconds, replace the check valve.
      6.  

    2.  

    To install:
    1. Screw the check valve onto the AIR pipe and tighten to 17 ft. lbs. (23 Nm).
    2.  
    3. Connect the right air pipe to the exhaust manifold and tighten to 15 ft. lbs. (20 Nm).
    4.  
    5. Install the hose and the clamp to the check valve.
    6.  
    7. Connect the negative battery cable, then check the system for proper operation.
    8.  

    Air Cross Under Pipe
    1. Disconnect the negative battery cable.
    2.  
    3. Remove the clamp and hose to the check valve, on both sides, from the cross under pipe.
    4.  
    5. Remove the clamp and hose to the air pump from the cross under pipe.
    6.  
    7. Raise and properly support the vehicle.
    8.  
    9. Remove the fasteners from the cross under pipe bracket.
    10.  
    11. Cut the cross under pipe near the center of the oil pan to aid in removal and remove the cross under pipe.
    12.  

    To install:
    1. Install the cross under pipe. Use an appropriate length of 5 / 8 heater hose to join both halves of the cross under pipe. Clamp both ends of the hose securely with stainless steel clamps.
    2.  
    3. Install the fasteners to the cross under pipe bracket and lower the vehicle.
    4.  
    5. Install the clamp and air hose to the air pump.
    6.  
    7. Install the clamp and hose to the check valves.
    8.  
    9. Connect the negative battery cable.
    10.  

    AIR Vacuum Bleed Valve Solenoid

    See Figure 17

    1. Disconnect the negative battery cable.
    2.  
    3. Detach the electrical connector from the solenoid.
    4.  
    5. Disconnect the vacuum harness from the solenoid.
    6.  



    Click image to see an enlarged view

    Fig. Fig. 17: AIR vacuum bleed valve solenoid (2) and vacuum harness (3)-1996-97 5.7L engine

    1. Remove the solenoid from the vehicle.
    2.  
    3. Installation is the reverse of the removal procedure.
    4.  

    AIR Solenoid or Pump Relay

    See Figure 18

    1. Disconnect the negative battery cable.
    2.  
    3. Remove the cover from the under hood electrical center #2.
    4.  
    5. Remove the AIR solenoid or pump relay, as applicable.
    6.  
    7. Installation is the reverse of the removal procedure.
    8.  



    Click image to see an enlarged view

    Fig. Fig. 18: The AIR solenoid and pump relay (2) locations

     
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