Intake Manifold: Service and Repair

Fig. 9 Plenum, runner & fuel line installation. 1985---88 Corvette, 1985---88 V8-305 W/EFI similar:

Fig. 10 Intake manifold installation. 1985---88 Corvette & V8-305 W/EFI:

1. Disconnect battery ground cable, drain cooling system and remove air intake duct and mass air flow sensor assembly.
2. Disconnect accelerator, cruise control and transmission cables, as equipped, and remove cable bracket.
3. Disconnect electrical connectors, coolant hoses and vacuum hoses, then remove throttle body from plenum.
4. Disconnect brake booster and vacuum hoses from plenum, noting position for installation.
5. Remove right intake runners, plenum retaining bolts and the plenum, Fig. 9.
6. Connect pressure gauge J-34370-1 or equivalent to pressure tap on fuel rail, position bleed hose in suitable container and slowly relieve fuel system pressure. Failure to relieve system pressure prior to disconnecting fuel system components may cause fire or personal injury.
7. Disconnect cold start valve fuel line and remove cold start valve.
8. Disconnect fuel lines and injector harness connectors.
9. Loosen fuel rail bolts and raise fuel rail assembly.
10. Remove remaining manifold runners, then the fuel rail assembly.
11. Disconnect electrical connectors and vacuum hoses necessary to allow manifold removal, noting position for installation.
12. Disconnect wires from spark plugs, then remove distributor cap assembly.
13. Rotate crankshaft until No. 1 cylinder is at TDC on compression stroke, mark position of distributor rotor, then remove distributor.
14. Disconnect upper radiator hose from thermostat housing and remove air injection pump brace.
15. Disconnect EGR pipe and heater control vacuum hose from intake.
16. Remove thermostat housing, then the manifold retaining bolts and manifold.
17. Ensure gasket surfaces are clean and dry, then install gaskets on cylinder head with blocked openings toward rear of engine.
18. Bend gasket tabs flush with rear face with cylinder head, then apply a 3/16 inch bead of RTV sealer to front and rear ridges of cylinder block.
19. Apply Loctite 1052624 or equivalent to manifold bolts.
20. Install manifold and torque bolts in sequence shown in Fig. 10.
21. Reverse remaining procedure to complete installation.

Torque components as follows:
Intake Manifold 35 Ft. Lbs.
Intake plenum runners 20 Ft. Lbs.
Fuel rails 7 Ft. Lbs.
Thermostat housing 20 Ft. Lbs.