Intake Manifold: Service and Repair

Intake Manifold & Throttle Body:

REMOVAL:

1. Verify the ignition switch is OFF.
2. Drain the coolant from the radiator.
3. Disconnect the negative battery cable.
4. Remove the fuel cap to relieve the fuel tank pressure.
5. Relieve the system fuel pressure at the pressure relief valve using EFI pressure Gauge T80L-9974-B or equivalent.
6. Disconnect the electrical connectors from:
a. Throttle position sensor.
b. Air bypass valve.
c. Fuel injector wiring harness at the main engine harness and at the water temperature sensor.
d. Air charge temperature sensor.
e. Engine coolant temperature sensor.
f. Ignition control assembly.
7. Disconnect the vacuum lines from:
a. Upper intake manifold tree. Label the locations for reassembly.
b. EGR valve.
c. Fuel pressure regulator.
d. Canister purge line.
8. Remove the throttle linkage shield, and disconnect the throttle linkage and cruise control. Unbolt the accelerator cable from the bracket and position the cable out of the way.
9. Disconnect the air intake hose and crankcase vent hose.
10. Disconnect the PCV system by disconnecting the hose from the fitting on the underside of the upper intake manifold.
11. Loosen the hose clamp on the water bypass line at the lower intake manifold, and disconnect the hose.
12. Disconnect the EGR tube from the EGR valve by removing the flange nut.
13. Remove the five upper intake manifold retaining bolts.
14. Remove the upper intake manifold and air throttle body.
15. Clean gasket sealing surfaces.

INSTALLATION:

1. Verify that the gasket sealing surfaces are clean.
2. Place a new gasket on the lower intake manifold and install the upper intake manifold in position.
3. Install the five retaining bolts and tighten to 20-30 Nm (15-22 lb.ft).

NOTE: The three bolts with the stud heads go in hole positions 2, 3, and 4.

4. Connect the fuel supply and return lines to the fuel supply manifold.
5. Reinstall the spring lock coupling retaining clips on the fuel outlet and return fittings.
6. Connect the EGR tube to the EGR valve, and tighten to 25-30 Nm (18-28 lb.ft).
7. Connect the water bypass line, and tighten the clamp to 1.4-2.2 Nm (12-20 lb.in).
8. Connect the PCV system hose to the fitting on the underside of the upper intake manifold.
9. Connect the upper intake manifold vacuum connections to:
a. Upper intake manifold vacuum tree.
b. EGR valve.
c. Fuel pressure regulator.
d. Canister purge line.
10. Hold the accelerator cable bracket in position on the upper manifold and install the retaining bolt, and tighten to 13.5-20.5 Nm (10-15 lb.ft).
11. Install the accelerator cable to the bracket.
12. Connect the accelerator cable and cruise control. Install the throttle linkage shield.
13. Connect the electrical connectors to:
a. Throttle position sensor.
b. Fuel injector wiring harness.
c. Fuel injector wiring harness at the coolant temperature indicator sensor.
d. Air charge temperature sensor.
e. Engine coolant temperature sensor.
f. Ignition control assembly.
g. Air bypass valve.
14. Connect the air intake hose and crankcase vent hose.
15. Connect the negative battery cable.
16. Fill the radiator with coolant.
17. Replace the fuel pressure relief cap, then pressurize the fuel system. With the engine OFF, turn the ignition ON then OFF at least six times, with the ON time for 15 seconds each time. Check for fuel leaks.
18. Start the engine and run at idle until normal operating temperature stabilizes. Check for coolant and fuel leaks.
19. Check for proper engine idle speed and operation.