GM Storm/Spectrum 1985-1993 Repair Guide

Intake Manifold

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REMOVAL & INSTALLATION



Spectrum

See Figure 1

  1. Disconnect the negative battery terminal from the battery and drain the cooling system.
  2.  
  3. Remove the bolt securing the alternator adjusting plate to the engine.
  4.  
  5. Disconnect and label all of the hoses attached to the air cleaner and remove the air cleaner.
  6.  
  7. Unplug the intake air temperature switch wiring connector. Remove the clamps for the AI hose, then remove the air cleaner.
  8.  
  9. Disconnect and label the hoses and electrical connectors attached to the carburetor, then disconnect the accelerator control cable
  10.  
  11. If equipped with air conditioning, disconnect the FICD vacuum hose, the pressure tank control valve hose, the distributor 3-way connector hose and the VSV wiring connector.
  12.  
  13. Remove the carburetor attaching bolts, located beneath the intake manifold, then remove the carburetor and the EFE heater.
  14.  
  15. At the intake manifold, remove the PCV hose, the water bypass hose, the heater hoses, the EGR valve/canister hose, the distributor vacuum advance hose and the ground wires.
  16.  
  17. Unplug the thermometer unit switch wiring connector.
  18.  
  19. Remove the intake manifold attaching nuts/bolts and the intake manifold.
  20.  
  21. Thoroughly clean the intake manifold and cylinder head sealing surfaces.
  22.  

To install:
  1. Install the intake manifold to the cylinder head using a new gasket.
  2.  
  3. Tighten the intake manifold fasteners to 17 ft. lbs. (23 Nm).
  4.  
  5. Attach new gaskets to the top and bottom of the EFE heater and install the carburetor.
  6.  
  7. Install the remaining components in the reverse order of removal.
  8.  
  9. Adjust the accelerator control cable.
  10.  
  11. Install the alternator and, if equipped, A/C compressor belts and adjust belt tension.
  12.  
  13. Refill the engine with coolant.
  14.  
  15. Connect the negative battery cable, start the engine and check for leaks.
  16.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the top end engine components - 1.5L engine

Storm

The Geo Storm engines utilize 2 piece intake manifolds consisting of an upper and a lower portion. The upper portion is referred to as the common chamber. The lower portion is known as the induction port.

EXCEPT TWINCAM ENGINE

See Figure 2

  1. Properly relieve the fuel system pressure, then disconnect the battery negative cable and drain the cooling system.
  2.  

The cooling system must be drained if the entire manifold assembly, common chamber and induction port, is to be removed. If only the common chamber is being removed, the cooling system may remain filled.

  1. Disconnect the ignition coil wire, then remove the accelerator cable from the throttle valve and the common chamber.
  2.  
  3. Unplug the 2 cable harness connectors, located near the left shock tower.
  4.  
  5. Disconnect the cable harness from the Intake Air Temperature (IAT) sensor, the Throttle Position (TP) sensor and the Intake Air Control (IAC) valve.
  6.  
  7. Remove the breather hose from the intake air duct and the duct from the throttle body, then the PCV hose from the valve cover.
  8.  
  9. Tag and disconnect the EGR valve and EVAP canister vacuum hoses from the throttle valve.
  10.  
  11. Disconnect the EGR pipe from the EGR valve and the exhaust manifold.
  12.  
  13. Remove the common chamber bracket bolt, then the throttle body assembly bolts and the throttle body.
  14.  
  15. Remove the coolant bypass pipe clip bolt, then disconnect the MAP sensor from the common chamber.
  16.  
  17. Disconnect the brake booster vacuum hose, then the EVAP canister vacuum hose from the common chamber and the throttle body.
  18.  
  19. Disconnect the pressure regulator vacuum hose from the common chamber, then the EGR vacuum hose.
  20.  
  21. Remove the engine hanger bolt, then remove 2 nuts and 6 bolts attaching the common chamber. Remove the common chamber from the vehicle.
  22.  
  23. Unplug the 2 cable harness connectors from the distributor.
  24.  
  25. Disconnect the fuel feed hose from the engine side and the fuel return hose from the chassis side.
  26.  
  27. Remove the 2 nuts and 8 bolts retaining the induction port to the cylinder, then remove the induction port from the engine.
  28.  
  29. Thoroughly clean all gasket mating surfaces.
  30.  

To install:
  1. Position the induction port to the engine, using a new gasket. Install the port nuts and bolts, then tighten the fasteners to 17 ft. lbs. (23 Nm).
  2.  
  3. Connect the fuel feed and return lines.
  4.  
  5. Install the 2 cable wiring harness connectors to the distributor.
  6.  
  7. Install the common chamber, using a new gasket, onto the induction port. Torque nuts and bolts to 17 ft. lbs. (23 Nm).
  8.  
  9. Install the coolant bypass pipe clip bolts.
  10.  
  11. Install the throttle body with a new gasket. Torque throttle valve bolts to 17 ft. lbs. (23 Nm).
  12.  
  13. Connect the EGR pipe flange to the exhaust manifold. Torque flange bolts to 17 ft. lbs. (23 Nm).
  14.  
  15. Connect the EGR vacuum hose, then the pressure regulator vacuum hose to the intake manifold (common chamber).
  16.  
  17. Connect the EVAP canister vacuum hose to the common chamber and the throttle body.
  18.  
  19. Connect the brake booster vacuum hose, install the MAP sensor to the common chamber and connect the PCV hose to the valve cover.
  20.  
  21. Connect the intake air duct to the throttle body, then connect the breather hose to the intake air duct.
  22.  
  23. Connect the cable harness to the IAT sensor, TP sensor and the IAC valve.
  24.  
  25. Connect the 2 cable harness connectors, located near the left shock tower.
  26.  
  27. Connect the accelerator cable to the throttle body and to the intake manifold (common chamber).
  28.  
  29. Connect the ignition coil wire, then connect the battery negative cable.
  30.  
  31. Fill cooling system, then start engine and check for leaks.
  32.  



Click image to see an enlarged view

Fig. Fig. 2: Exploded view of the top end engine components - 1.6L SOHC engine

1.6L TWINCAM ENGINE

See Figure 3

  1. Properly relieve the fuel system pressure. Disconnect the battery negative cable, then remove the ground cable terminal from the common chamber.
  2.  
  3. Remove the PCV hose and the air intake duct, then disconnect the accelerator cable from the intake air duct.
  4.  
  5. Disconnect the accelerator cable from the throttle valve.
  6.  
  7. Disconnect the MAP sensor hose from the MAP sensor, then the vacuum hose from the brake vacuum booster.
  8.  
  9. Tag and disconnect the 2 canister hoses from the pipes located on the common chamber.
  10.  
  11. Remove the canister pipe bracket from the common chamber.
  12.  
  13. Disconnect the vacuum hose from the fuel pressure regulator, then the vacuum hose from the induction control valve port.
  14.  
  15. Remove the throttle valve from the common chamber.
  16.  
  17. Remove the alternator harness clip, then the 3 fuel injector harness cable clips.
  18.  
  19. Loosen the EGR pipe bracket on the exhaust manifold, then loosen the EGR clip from the thermostat housing.
  20.  
  21. Remove the 2 common chamber bracket attaching bolts, located on the left side of the engine and the engine hanger bolt, located on the right side of the common chamber.
  22.  
  23. Remove the 10 bolts and 2 nuts attaching the common chamber to the induction port, then remove the common chamber from the engine.
  24.  
  25. Remove the 2 oil cooler pipe nuts from the studs under the induction port.
  26.  
  27. Disconnect the fuel feed and return lines, then remove the 2 fuel rail retaining bolts. Remove the fuel injector harness bracket retaining bolts.
  28.  
  29. Remove the fuel injector harness, fuel rail and fuel injector assembly from the induction port.
  30.  
  31. Remove the VSV harness connector from the induction port.
  32.  
  33. Remove the 7 bolts and 2 nuts attaching the induction port to the cylinder head, then remove the induction port assembly from the vehicle.
  34.  

To install:
  1. Thoroughly clean all gasket mating surfaces.
  2.  
  3. Install the induction port using a new gasket. Tighten the retainers to 17 ft. lbs. (23 Nm).
  4.  
  5. Install the VSV harness, then install the fuel injector harness, fuel rail and injectors assembly.
  6.  
  7. Install the fuel injector harness bracket bolts and the fuel rail retaining bolts.
  8.  
  9. Connect the fuel feed and return lines, then install the 2 oil cooler pipe clip bolts to the studs under the induction port.
  10.  
  11. Install the common chamber with a new gasket onto the induction port assembly. Torque nuts and bolts to 17 ft. lbs. (23 Nm).
  12.  
  13. Install the common chamber bracket bolts, located on the left side of the engine and the hanger bolt, located on the right side of the engine.
  14.  
  15. Install the EGR pipe bracket bolts on the exhaust manifold and the EGR clip on the thermostat housing. Torque EGR bracket bolts to 32 ft. lbs. (44 Nm).
  16.  
  17. Install the alternator harness cable clip, then the 3 fuel injector harness cable clips.
  18.  
  19. Install the throttle valve onto the common chamber, then connect the induction control valve vacuum hose.
  20.  
  21. Connect the fuel pressure regulator vacuum hose to the common chamber.
  22.  
  23. Connect the canister pipe bracket onto the common chamber, then connect the canister hoses to the pipes on the common chamber.
  24.  
  25. Connect the brake booster vacuum hose, then the MAP sensor hose to the MAP sensor.
  26.  
  27. Connect the accelerator cable to the throttle valve. Install the PCV hose and the intake air duct. Connect the cable ground terminal to the common chamber.
  28.  
  29. Connect the battery negative cable and fill cooling system, then start the engine and check for leaks.
  30.  



Click image to see an enlarged view

Fig. Fig. 3: Intake and exhaust manifolds with related components - 1.6L DOHC engine

1.8L TWINCAM ENGINE

See Figure 4

  1. Properly relieve the fuel system pressure. Disconnect the battery negative cable, then remove the ground cable bolts from the common chamber.
  2.  
  3. Remove the ventilation hose from the intake air duct.
  4.  
  5. Unplug the Throttle Position (TP) sensor, Intake Air Control (IAC) valve and the cold start injector electrical connectors.
  6.  
  7. Remove the air intake duct and the air cleaner from the throttle body.
  8.  
  9. Remove the 2 retaining bolts and the accelerator cable bracket from the common chamber. Disconnect the accelerator cable from the throttle lever.
  10.  
  11. Remove the PCV hose and the Manifold Absolute Pressure (MAP) sensor hose from the common chamber.
  12.  
  13. Remove the pressure regulator hose from the common camber, then remove the 2 retaining bolts and the solenoid vacuum valve assembly from the chamber.
  14.  
  15. Remove the Intake Air Temperature (IAT) sensor from the common chamber.
  16.  
  17. Position and drain pan and a rag to catch any escaping fluid, then remove the 2 coolant hoses from the throttle body.
  18.  
  19. Tag and disconnect the vacuum hoses from the common chamber.
  20.  
  21. Remove the 2 bolts and the engine lift bracket from the common chamber.
  22.  
  23. Remove the 3 bolts and 2 nuts attaching the common chamber to the intake manifold (known as the induction port on earlier engines).
  24.  
  25. Remove 1 bolt from the fuel pipe bracket, then remove 2 bolts and the EGR pipe from the exhaust manifold.
  26.  
  27. Remove 1 bolts from the EGR pipe bracket. Remove the EGR pipe nut and pipe from the EGR valve.
  28.  
  29. Unplug the fuel injector electrical connectors, then remove the ground cable from the intake manifold.
  30.  
  31. Remove the brake booster vacuum hose, then raise and support the vehicle safely.
  32.  
  33. Loosen the hose clamp, then disconnect the fuel return hose from the intake manifold.
  34.  
  35. Remove 1 bolt and set the oil cooler pipe aside, then remove the 2 bolts and the left intake manifold brace,
  36.  
  37. Remove 1 bolt, 1 nut and the right side intake manifold brace.
  38.  
  39. Remove the 4 lower intake manifold retaining bolts, then remove the supports and carefully lower the vehicle for underhood access.
  40.  
  41. Remove the 2 upper intake manifold retaining nuts and the 3 upper bolts, then remove the intake from the cylinder head.
  42.  

To install:
  1. Thoroughly clean all gasket mating surfaces.
  2.  
  3. Install the intake manifold to the cylinder head using a new gasket. Tighten the upper retainers to 17 ft. lbs. (23 Nm), then raise and support the vehicle safely.
  4.  
  5. Install the lower manifold retaining bolts and tighten to 17 ft. lbs. (23 Nm).
  6.  
  7. Install the right, then left manifold braces and tighten the retainers to 15 ft. lbs. (20 Nm).
  8.  
  9. Reposition the oil cooler pipe and secure using the retaining bolt. Tighten the bolt to 89 inch lbs. (10 Nm).
  10.  
  11. Install the fuel return hose to the intake and secure using the hose clamp, then remove the supports and carefully lower the vehicle.
  12.  
  13. Connect the brake booster vacuum hose, then connect the ground cable bolt to the manifold. Tighten the bolt to 71 inch lbs. (8 Nm).
  14.  
  15. Install the fuel injector electrical connectors.
  16.  
  17. Install the EGR pipe to the valve and tighten the pipe nut to 11 ft. lbs. (15 Nm).
  18.  
  19. Install the bolt to the EGR pipe bracket and tighten to 89 inch lbs. (10 Nm). Install the EGR pipe to the exhaust manifold and tighten the bolts to 89 inch lbs. (10 Nm).
  20.  
  21. Install the bolt to the fuel pipe bracket and tighten to 89 inch lbs. (10 Nm).
  22.  
  23. Install the common chamber to the intake manifold using a new gasket. Tighten the retainers to 17 ft. lbs. (23 Nm).
  24.  
  25. Install the engine lift bracket to the common chamber and tighten the retaining bolts to 18 ft. lbs. (25 Nm).
  26.  
  27. Install the vacuum hoses to the common chamber, then install the 2 coolant hoses to the throttle valve.
  28.  
  29. Install the IAT sensor electrical connector to the chamber.
  30.  
  31. Install the SV valve assembly to the chamber using the retaining bolts and tighten to 89 inch lbs. (10 Nm).
  32.  
  33. Connect the pressure regulator and MAP sensor hoses to the common chamber.
  34.  
  35. Connect the PCV hose to the common chamber.
  36.  
  37. Connect the accelerator cable to the throttle lever, then install the cable bracket to the chamber and tighten the bolts to 89 inch lbs. (10 Nm).
  38.  
  39. Check and adjust the accelerator cable, as necessary. Make sure that the cable does not hold the throttle open when the accelerator is released.
  40.  
  41. Install the air intake duct to the throttle body.
  42.  
  43. Install the wiring harness connectors to the TP sensor, IAC valve and cold start injector.
  44.  
  45. Connect the ventilation hose to the intake air duct.
  46.  
  47. Install the ground cable bolts to the chamber and tighten to 71 inch lbs. (8 Nm).
  48.  
  49. Connect the battery negative cable and fill cooling system, then start the engine and check for leaks.
  50.  



Click image to see an enlarged view

Fig. Fig. 4: Exploded view of the top end engine components - 1.8L engine (1.6L DOHC engine similar)

 
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