Intake Manifold: Service and Repair

REMOVAL
1. Open hood and install protective covers.
2. Ensure ignition switch is in OFF position.
3. Drain coolant from radiator.
4. Disconnect battery ground cable and secure it out of the way.
5. Remove fuel cap to relieve fuel tank pressure.
6. Release pressure from fuel system at the fuel pressure relief valve using EFI Pressure Gauge T80L-9974-B or equivalent. The fuel pressure relief valve is located on the fuel line in the upper RH corner of the engine compartment. To gain access to the fuel pressure relief valve, the valve cap must first be removed.

Upper And Lower Intake Manifold Sensors:

7. Disconnect electrical connectors at:
a. Throttle position sensor.
b. Injector wiring harness.
c. Knock sensor.
d. Air charge temperature sensor.
e. Engine coolant temperature sensor.
f. Air bypass valve.
g. Fan switch.
h. EGR valve.

Upper Intake Manifold And Components:

8. Disconnect upper intake manifold vacuum fitting connections by disconnecting:
a. Vacuum lines at upper intake manifold vacuum tree. Labeling the hose locations with tape is recommended to aid reinstallation.
b. Vacuum line to fuel pressure regulator.
9. Disconnect throttle linkage, cruise control, and kickdown cable. Unbolt accelerator cable from bracket and position cable out of way.
10. Disconnect air intake hose.
11. Disconnect PCV system by disconnecting hose from fitting on underside of upper intake manifold.
12. Loosen hose clamp on water bypass line at lower intake manifold, and disconnect hose.

EGR Tube And EGR Valve:

13. Disconnect EGR tube from EGR valve by removing flange nut.

Engine Oil Dipstick And Bracket:

14. Remove engine oil dipstick bracket retaining screw.
15. Remove four upper intake manifold retaining nuts.

Upper Intake Manifold And Throttle Body Removal:

16. Remove upper intake manifold and air throttle body assembly.
17. Disconnect EVAP canister purge hose from throttle body.
18. Remove spring lock coupling retaining clips from fuel inlet and return fittings.

Fuel Supply And Return Fittings:

19. Disconnect the Push Connect Fitting at the fuel supply manifold fuel supply and fuel return lines using Quick Connect Removal Tool D87L-9280-A or B or equivalent.

Fuel Injector Harness:

20. Disconnect the electrical connectors from all four fuel injectors and move harness aside.

Fuel Injector Manifold And Fuel Injectors:

21. Remove two fuel supply manifold retaining bolts. Carefully remove fuel supply manifold and injectors.

NOTE: Injectors can be removed from the fuel supply manifold at this time by exerting a slight twisting/pulling motion.

22. Remove four bottom retaining bolts from lower manifold.
23. Remove four upper retaining bolts from lower manifold.

Lower Intake Manifold Removal:

NOTE: The front two bolts also secure an engine lift bracket. Remove lower intake manifold assembly.

INSTALLATION
1. Clean and inspect the mounting faces of the fuel charging manifold assembly and the cylinder head. Both surfaces must be clean and flat.
2. Clean and oil manifold bolt threads.

Lower Intake Manifold Removal:

3. Install a new gasket.
4. Position the lower manifold assembly to head and install engine lift bracket. Install four upper manifold retaining bolts finger-tight.

Lower Intake Manifold Bolt Tightening Sequence:

5. Install four remaining manifold bolts. Tighten all eight manifold bolts in numerical sequence in two steps:
a. Step 1. 7-10 Nm (5-7 ft lb)
b. Step 2. 26-38 Nm (20-29 ft lb).

Fuel Injector Manifold And Fuel Injectors:

6. Install the fuel supply manifold and injectors with two retaining bolts. Tighten bolts to 19-29 Nm (14-21 ft lb).
7. Connect four electrical connectors to injectors.
8. Ensure that gasket surfaces of upper and lower intake manifolds are clean.

Upper Intake Manifold And Throttle Body Removal:

9. Place a new service gasket on the lower intake manifold assembly. Place the upper intake manifold in position.

Upper Intake Manifold Bolt Tightening Sequence:

10. Install four retaining bolts. Tighten in sequence to 20-30 Nm (15-22 ft lb).
11. Install engine oil dipstick.
12. Reconnect spring lock coupling retaining clips to fuel inlet and return fittings.
13. Connect fuel supply and fuel return lines to fuel supply manifold.
14. Connect EGR tube to the EGR valve. Tighten to 8-11.5 Nm (6-8.5 ft lb).
15. Connect the water bypass line. Tighten clamp to 1.4-2.2 Nm (12-20 in lb).
16. Connect the PCV system hose to the fitting on the underside of the upper intake manifold.
17. Using Teflon tape on threads, install upper intake manifold vacuum tree. Tighten to 16-24 Nm (12-18 ft lb), with final orientation.
18. Connect upper intake manifold vacuum connections:
a. Vacuum lines at upper intake manifold vacuum tree.
b. Fuel pressure regulator.
19. Hold accelerator cable bracket in position on upper manifold and install retaining bolt. Tighten bolt to 13.5-20.5 Nm (10-15 ft lb).
20. Install accelerator cable to bracket.
21. Position a new gasket on fuel charging assembly air throttle body mounting flange.
22. Connect EVAP canister purge hose to throttle body.

Throttle Body To Upper Intake Manifold:

23. Install air throttle body to fuel charging assembly. Install four retaining bolts. Tighten to 20-30 Nm (15-22 ft lb).
24. Connect accelerator cable and cruise control.
25. Connect electrical connectors to:
a. Throttle position sensor.
b. Injector wiring harness.
c. Knock sensor.
d. Air charge temperature sensor.
e. Engine coolant temperature sensor.
f. Air bypass valve.
g. Fan switch.
h. EGR valve.
26. Connect air intake hose, air bypass hose and crankcase vent hose.
27. Connect battery ground cable.

NOTE: On vehicles equipped with Electronic Engine Control (EEC), when the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the EEC processor relearns its adaptive strategy. The vehicle may need to be driven 10 miles or more to relearn the strategy.

28. Install engine coolant.
29. Replace fuel pressure relief cap, then build up fuel pressure as follows:
a. Without starting the engine, turn key back and forth at least six times from ON to OFF position, leaving key ON for 15 seconds each time.
b. Then, check for fuel leaks.
30. Use EEC self-test connector to check proper EEC-IV system functioning.
31. Start engine and allow to run at idle until engine temperature stabilizes. Check for cooling system leaks.
32. Verify correct engine idle.
33. Remove protective covers and close hood.