GM Prizm/Nova 1985-1993 Repair Guide

Intake Manifold

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REMOVAL & INSTALLATION



1988 VIN Code 5 Engine

See Figures 1 and 2

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the air cleaner assembly.
  2.  
  3. Remove the upper radiator hose at the engine.
  4.  
  5. Disconnect the accelerator cable and, on automatic transmissions, the throttle valve cable.
  6.  
  7. Label and disconnect vacuum hoses at the manifolds.
  8.  
  9. Disconnect and remove the fuel delivery pipe (fuel rail) and remove the injectors. During removal, be careful not to drop the injectors.
  10.  


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. Have a Class B-C (dry powder) fire extinguisher within arm's reach at all times.



Click image to see an enlarged view

Fig. Fig. 1: Removing the fuel rails and injectors - 1988 VIN Code 5 engine

  1. Disconnect the vacuum hose to the brake booster and remove the heat shield(s) from the manifold(s).
  2.  
  3. Safely raise the car and support it on jackstands.
  4.  
  5. Disconnect the wire for the water temperature sensor and remove the water outlet housing (thermostat housing) and the bypass pipe.
  6.  
  7. Remove the exhaust bracket and disconnect the exhaust pipe at the manifold. Remove the support bracket for the intake manifold.
  8.  
  9. Lower the vehicle to the ground.
  10.  
  11. Remove the intake manifold with the air control valve and gaskets and/or remove the exhaust manifold with its gaskets.
  12.  



Click image to see an enlarged view

Fig. Fig. 2: Check for warpage in three positions - 1988 VIN Code 5 engine

  1. Using a precision straight edge and a feeler gauge, check the mating surfaces of the manifolds for warpage. If the warpage is greater than the maximum allowable specification, replace the manifold.
  2.  

Maximum allowable warpage:


Intake Manifold: 0.05mm
 
Exhaust Manifold: 0.3mm
 
Air Control Valve: 0.05mm.
 

To install:
  1. When reinstalling, always use new gaskets and make sure they are properly positioned. Place the manifold(s) in position and loosely install the nuts and bolts until all are just snug. Double check the placement of the manifold(s) and in 2 passes tighten the retaining nuts and bolts. The exhaust manifold retaining bolts should be tightened to 18 ft. lbs. (25 Nm) and the intake manifold bolts should be tightened to 20 ft. lbs. (27 Nm). The bolts for the intake support bracket should also be tightened to 20 ft. lbs. (27 Nm)
  2.  
  3. With the manifold(s) in place, elevate and support the vehicle; install the support bracket for the intake manifold and connect the exhaust pipe to the exhaust manifold. Attach the exhaust bracket.
  4.  
  5. Install the bypass pipe, the water outlet housing and connect the wiring to the water temperature sensor.
  6.  
  7. Lower the car to the ground and install the heat shield(s) on the manifolds.
  8.  
  9. Connect the vacuum hose for the brake vacuum booster.
  10.  
  11. Install the fuel delivery pipe and the injectors. Tighten the mounting bolts to 13 ft. lbs.
  12.  
  13. Observing the labels made earlier, install the vacuum lines. Be careful of the routing and make sure that each line fits snugly on its port.
  14.  
  15. Double check each line for crimps or twists.
  16.  
  17. Connect the accelerator cable and throttle valve cable (automatic trans.)
  18.  
  19. Reconnect the upper radiator hose.
  20.  
  21. Install the air cleaner assembly.
  22.  
  23. Refill the coolant.
  24.  
  25. Connect the negative battery cable.
  26.  

1989-90 VIN Code 6 Engine

See Figures 3 and 4

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system.
  4.  


CAUTION
When draining the coolant, keep in mind that cats and dogs are attracted by the ethylene glycol antifreeze, and are quite likely to drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain the coolant into a sealable container. Coolant should be reused unless it is contaminated or several years old.

  1. Remove the air cleaner assembly.
  2.  
  3. Label and disconnect the vacuum hoses at the manifold.
  4.  
  5. Label and disconnect the wiring to the throttle position sensor, the cold start injector, the injector connectors, the air control valve and the vacuum sensor.
  6.  
  7. Disconnect the cold start injector pipe.
  8.  


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. Have a Class B-C (dry powder) fire extinguisher within arm's reach at all times.



Click image to see an enlarged view

Fig. Fig. 3: Removing the cold start injector line at the intake manifold - 1989-90 VIN code 6 engine

  1. Disconnect the water hose from the air valve.
  2.  
  3. Raise and safely support the car on jackstands.
  4.  
  5. Remove the intake manifold support bracket. Lower the car to the ground.
  6.  
  7. Remove the 7 bolts, 2 nuts and the ground cable. Remove the intake manifold and its gaskets.
  8.  



Click image to see an enlarged view

Fig. Fig. 4: Intake manifold assembly - 1989-90 VIN code 6 engine

  1. Measure the intake manifold mating surface with a precision straight edge and a feeler gauge. If the warpage exceeds 0.2mm, the manifold must be replaced.
  2.  

To install:
  1. To reassemble, install the manifold with new gaskets in position. Attach the 7 bolts, 2 nuts and the ground cable connector.
  2.  
  3. Raise and safely support the car; install the manifold support bracket and its bolts. Lower the car to the ground.
  4.  
  5. Tighten the manifold mounting nuts and bolts evenly to 14 ft. lbs. (19 Nm).
  6.  
  7. Connect the water hose to the air valve.
  8.  
  9. Connect the fuel line to the cold-start injector.
  10.  
  11. Connect the wiring to the throttle position sensor, the cold start injector, the injector connectors, the air control valve and the vacuum sensor.
  12.  
  13. Observing the labels made earlier, install the vacuum lines. Be careful of the routing and make sure that each line fits snugly on its port. Double check each line for crimps or twists.
  14.  
  15. Connect the accelerator and throttle valve (automatic trans.) cables to their brackets.
  16.  
  17. Refill the coolant.
  18.  
  19. Install the air cleaner assembly and connect the negative battery cable.
  20.  

1990 VIN Code 5 Engine 1991-92 All Engines
  1. Disconnect the negative battery cable.
  2.  
  3. Drain the cooling system.
  4.  
  5. Remove the air cleaner assembly.
  6.  
  7. Remove the upper radiator hose at the engine.
  8.  
  9. Disconnect the accelerator cable and, on automatic transaxles, the throttle valve cable.
  10.  
  11. Label and disconnect vacuum hoses at the manifolds.
  12.  
  13. Disconnect and remove the fuel delivery pipe (fuel rail) and remove the injectors. During removal, be careful not to drop the injectors.
  14.  


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. Have a Class B-C (dry powder) fire extinguisher within arm's reach at all times.

  1. Disconnect the vacuum hose to the brake booster and remove the heat shield(s) from the manifold(s).
  2.  
  3. Raise the vehicle and support it safely.
  4.  
  5. Disconnect the wire for the water temperature sensor and remove the water outlet housing (thermostat housing) and the bypass pipe.
  6.  
  7. Remove the exhaust bracket and disconnect the exhaust pipe at the manifold. Remove the support bracket for the intake manifold.
  8.  
  9. Lower the vehicle to the ground.
  10.  
  11. Remove the intake manifold with the air control valve and gaskets and/or remove the exhaust manifold with its gaskets.
  12.  
  13. Using a precision straight edge and a feeler gauge, check the mating surfaces of the manifolds for warpage. If the warpage is greater than the maximum allowable specification, replace the manifold.
  14.  

Maximum allowable warpage:


Intake Manifold: 0.05mm
 
Exhaust Manifold: 0.3mm
 
Air Control Valve: 0.05mm.
 

To install:
  1. When reinstalling, always use new gaskets and make sure they are properly positioned. Place the manifold(s) in position and loosely install the nuts and bolts until all are just snug. Double check the placement of the manifold(s) and in 2 passes tighten the retaining nuts and bolts. The exhaust manifold retaining bolts should be tightened to 18 ft. lbs. (25 Nm) and the intake manifold bolts should be tightened to 20 ft. lbs. (27 Nm). The bolts for the intake support bracket should also be tightened to 20 ft. lbs. (27 Nm).
  2.  
  3. With the manifold(s) in place, elevate and support the vehicle; install the support bracket for the intake manifold and connect the exhaust pipe to the exhaust manifold. Attach the exhaust bracket.
  4.  
  5. Install the bypass pipe, the water outlet housing and connect the wiring to the water temperature sensor.
  6.  
  7. Lower the vehicle to the ground and install the heat shield(s) on the manifolds.
  8.  
  9. Connect the vacuum hose for the brake vacuum booster.
  10.  
  11. Install the fuel delivery pipe and the injectors. Tighten the mounting bolts to 13 ft. lbs. (18 Nm).
  12.  
  13. Observing the labels made earlier, install the vacuum lines. Be careful of the routing and make sure that each line fits snugly on its port.
  14.  
  15. Double check each line for crimps or twists.
  16.  
  17. Connect the accelerator cable and throttle valve cable (automatic trans.)
  18.  
  19. Reconnect the upper radiator hose.
  20.  
  21. Install the air cleaner assembly.
  22.  
  23. Refill the coolant.
  24.  
  25. Connect the negative battery cable.
  26.  

1993 All Engines

On the 1993 engines, the upper intake air chamber and intake manifold can be separated. A metal gasket is used to improve sealing performance. No cold start injector assembly is used on the 1993 vehicles.

  1. Relieve the fuel pressure. Disconnect the negative battery cable.
  2.  
  3. Remove the air cleaner assembly. Drain the coolant.
  4.  
  5. Tag and remove all wires, hoses or cables in the way of intake manifold removal. Remove the intake manifold stay (bracket).
  6.  
  7. Remove the cold start injector pipe, if equipped.
  8.  
  9. Disconnect the electrical connectors and remove the fuel delivery pipe (fuel rail) and remove the injectors. During removal, be careful not to drop the injectors.
  10.  


CAUTION
The fuel system is under pressure. Release pressure slowly and contain spillage. Observe no smoking/no open flame precautions. Have a Class B-C (dry powder) fire extinguisher within arm's reach at all times.

  1. Remove the intake manifold retaining bolts. Remove the intake manifold from the vehicle.
  2.  

To install:
  1. Clean the gasket mating surfaces being careful not to damage them. Check the mating surfaces for warpage with a straight edge. The specification for maximum warpage on the intake manifold is 0.0079 in. (0.20mm). If warpage is greater than maximum, replace the manifold.
  2.  
  3. Match the old gasket with the new one for an exact match. Use a new gasket when installing the manifold and tighten the bolts evenly and in several passes from the center outward to 20 ft. lbs. Install the intake manifold stay (bracket).
  4.  
  5. Install the cold start injector pipe, if equipped. Torque the cold start injector union bolt to 18 ft. lbs.
  6.  
  7. Install all necessary wires, hoses or cables. Install the air cleaner assembly.
  8.  
  9. Refill the cooling system. Connect the negative battery cable. Start the engine. Check for leaks and road test for proper operation.
  10.  

 
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