Models with a carburetor
1. Place a clean, dry container under the radiator, remove the plug, and drain the coolant from the radiator.
2. Remove the air filter and its casing from the carburetor.
3. Remove the air valve, EGR valve, air intake valve and air chamber (if the vehicle is equipped).
4. Tag and disconnect all wires from the carburetor and intake manifold.
5. Disconnect the fuel line from the carburetor and disconnect the throttle control cable from the carburetor.
6. Remove the carburetors from the intake manifold.
7. Remove the nuts securing the intake manifold to the cylinder head using the cross method (starting from the middle and moving in a cross order in both directions), then remove the manifold.
8. Using a putty spatula or a piece of hard plastic, clean the surfaces of the cylinder head adjacent to the gasket. Do not use razors or scrapers as they may damage the surfaces resulting in leakage.
9. If you are going to replace the manifold, then remount all necessary components on the new manifold.
For installation:
10. Using new gaskets, place them and the manifold on the cylinder head. Hand-tighten the nuts, starting from the center, then cross-tighten them. Nuts, to prevent leakage, must be tightened with the same tightening torque over the entire surface of the manifold. Correct tightening torques for cars:
- ACCORD 1984-85: 22 Nm.
- ACCORD 1986-89: 22 Nm.
- PRELUDE 1984-87: 32 Nm.
- PRELUDE 1988-90: 24 Nm.
11. Install the carburetor (s), making sure that the insulator or main gasket is not damaged and is properly positioned.
12. Connect fuel lines and throttle control cable. Adjust it if necessary.
13. Connect all electrical or vacuum connections to the carburetor and manifold.
14. Install emissions and air gauges remote for access. Always use new gaskets for the EGR valve. Carefully handle and install the air valve, air chamber and hoses.
15. Install the air filter with casing.
16. Fill the radiator with coolant.
17. Start the engine, carefully checking for fuel, coolant, or vacuum leaks. Check for a possible vacuum leak at the manifold gasket location.
For models with fuel injection
1. Place a clean, dry container under the radiator, remove the plug, and drain the coolant to a level below the intake manifold. Disconnect the coolant hoses from the intake manifold.
2. Tag and disconnect all vacuum hoses and electrical wires from the manifold. Disconnect the wires from the contacts on the EGR valve.
3. Correctly reduce fuel pressure.
4. Carefully remove the throttle, metal fuel lines and injectors. On 1988-91 PrElUDE and 1991 ACCORD vehicles, carefully remove the bypass valve housing from the intake manifold.
5. Remove the fast idle valve, air outlet valve, EGR valve and their retaining struts.
6. Remove the mounting bolts from the intake manifold struts and the struts themselves. While supporting the intake manifold, remove the nuts holding it to the cylinder head, remove the manifold and gasket from the cylinder head.
7. Using a putty knife or other suitable tool, clean the surfaces adjacent to the gasket. Check the surfaces for distortion with a ruler. Replace deformed parts.
If the surface of the intake manifold in contact with the cylinder head is warped, it should be machined or replaced.
For installation:
8. Using a new gasket, place the manifold in place and, while supporting it, secure the nuts to the rods.
9. Install support brackets below manifold. Tighten the bolt securing the bracket to the manifold to 22 Nm.
10. Starting with the inner or center nut, tighten in a criss-cross pattern as this will spread the stress on the cap evenly and there will be no leakage. The correct tightening torque for all vehicles with fuel injection is 22 Nm.
11. Install the air outlet valve, EGR valve and all other removed parts, and all gaskets should be replaced with new ones.
12. If the bypass valve assembly was removed, replace the gasket and install it on the manifold.
13. Install a new gasket and air collector or manifold chamber if removed as a separate unit. The nuts and bolts holding it are tightened with a force of 22 Nm.
14. Install the throttle and connect the cable to it.
15. Connect fuel lines. Always use new washers when assembling the housing.
16. Connect electrical and vacuum connectors.
17. Double check the installation of all parts, paying special attention to possible loose hoses, loose wires, loose nuts, check that the wires and hoses are correctly fastened (not too strong and weak), and forgotten tools.
18. Fill the radiator with coolant.
19. Start the engine, checking that the fuel, vacuum, and coolant hoses are properly connected, and that the manifold gasket is tight for vacuum leaks.