Fuel Injector Cleaning

This procedure covers the removal, cleaning, and reinstallation of the Rochester fuel injection system components on a 1966 Corvette 327ci V8, including the fuel meter assembly and injector nozzles.

Warnings

Tools required

Parts

• Fuel meter body O-ring set × 1 — Use OEM specification
• Fuel injector O-rings × 8 — Use OEM specification
• Fuel line sealing washers × 2 — Use OEM specification
• Intake manifold gasket set × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake.
2. Disconnect negative battery cable to prevent electrical shorts.
3. Allow engine to cool completely if recently operated.
4. Place fire extinguisher within easy reach of work area.
5. Prepare clean workspace for fuel injection components with shop towels to catch residual fuel.
6. Have replacement O-rings and gaskets ready before disassembly.

Procedure

1. 1

   Relieve fuel system pressure
   Remove the fuel tank cap to relieve tank pressure. Locate the fuel pump fuse or disconnect the fuel pump relay. Attempt to start the engine and allow it to run until it stalls from fuel starvation. Crank the engine for an additional 3-5 seconds to ensure all residual pressure is relieved. Reinstall the fuse or relay after pressure relief.
2. 2

   Remove air cleaner assembly
   Remove the wing nut securing the air cleaner lid. Lift off the air cleaner lid and set aside. Disconnect the crankcase breather hose from the air cleaner base. Remove the 4 bolts securing the air cleaner base to the fuel meter body and lift the assembly clear. Inspect and set aside the air cleaner gasket for reuse or replacement.
3. 3

   Disconnect fuel lines
   Place a drain pan beneath the fuel meter assembly to catch residual fuel. Using appropriate wrenches, disconnect the fuel inlet line from the fuel meter body. Disconnect the fuel return line from the pressure regulator. Cap or plug all open fuel lines immediately to prevent contamination and fuel spillage. Expect approximately 2-4 ounces of fuel spillage.
4. 4

   Disconnect electrical connections
   Disconnect the electrical connector from the fuel pressure switch on top of the fuel meter assembly. Tag and disconnect all injector electrical connectors. On the 1966 system, there are 8 individual injector connectors. Use masking tape to label each connector with its cylinder number to ensure correct reconnection.
5. 5

   Disconnect vacuum and throttle linkage
   Tag and disconnect all vacuum lines from the fuel meter body and throttle body assembly. There are typically 3 vacuum connections: manifold vacuum to pressure regulator, ported vacuum to distributor advance, and PCV system connection. Disconnect the throttle linkage at the throttle body. On automatic transmission vehicles, also disconnect the kickdown linkage.
6. 6

   Remove fuel meter assembly
   Remove the 8 bolts securing the fuel meter assembly to the intake manifold. The bolts are arranged in a circular pattern around the perimeter of the fuel meter body. Carefully lift the entire fuel meter assembly straight up and off the intake manifold. The injector nozzles will remain inserted in the manifold runners initially. Set the fuel meter assembly on clean shop towels.
7. 7

   Remove injector nozzles
   Carefully pull each of the 8 injector nozzles from their mounting ports in the intake manifold runners. The nozzles are held by O-rings and should pull free with moderate force. If a nozzle is stuck, gently twist while pulling to break the O-ring seal. Inspect each nozzle for damage or excessive carbon buildup at the tip.
8. 8

   Clean injector nozzles
   Using the fuel injector cleaning kit, connect each injector to the cleaning adapter. Follow the cleaning kit manufacturer's instructions for solution type and pressure. Typically, flush each injector with cleaning solution at 30-40 psi for 3-5 minutes or until spray pattern is symmetrical and atomized. Inspect spray pattern by spraying into a clear container. The pattern should be a fine, conical mist, not a stream or uneven spray. Clean any carbon deposits from the exterior of the injector tips using a soft wire brush.
9. 9

   Clean fuel meter body and manifold surfaces
   Using a plastic scraper or soft wire brush, carefully remove all old gasket material from the fuel meter body mounting surface and the intake manifold mating surface. Do not use metal tools that could gouge the aluminum surfaces. Clean both surfaces thoroughly with brake cleaner or carburetor cleaner and wipe dry with clean shop towels. Inspect for any cracks or damage.
10. 10

    Replace O-rings on injectors
    Remove and discard all old O-rings from each injector nozzle. Each injector has 2 O-rings. Lubricate new O-rings lightly with clean engine oil or petroleum jelly. Roll the new O-rings onto each injector, ensuring they seat properly in the O-ring grooves without twisting or pinching.
11. 11

    Reinstall injector nozzles
    Insert each injector nozzle into its corresponding intake manifold runner port, aligning it carefully. Push each nozzle firmly into place until it seats completely against the manifold. Ensure the electrical connector orientation allows easy reconnection. All 8 injectors must be fully seated before proceeding.
12. 12

    Install new fuel meter gasket
    Position the new fuel meter body gasket onto the intake manifold surface, aligning all 8 injector openings and all bolt holes. Ensure the gasket is properly oriented with any alignment tabs or marks facing the correct direction as indicated on the gasket.
13. 13

    Reinstall fuel meter assembly
    Carefully lower the fuel meter assembly onto the intake manifold, guiding it over all 8 injector nozzles simultaneously. Align the mounting bolt holes. Apply light downward pressure to seat the assembly fully onto the gasket. Install all 8 mounting bolts finger-tight initially. Tighten the bolts in a crossing pattern (opposite sides) in two stages: first pass to snug, second pass to final tightness. Due to the aluminum construction, use moderate tightness to avoid stripping threads, approximately 12-15 ft-lbs.
14. 14

    Reconnect all connections
    Reconnect all 8 injector electrical connectors to their tagged positions. Reconnect the fuel pressure switch electrical connector. Reconnect all vacuum lines according to the tags applied during removal. Reconnect the throttle linkage and adjust for proper operation with slight freeplay. On automatic transmission vehicles, reconnect and adjust the kickdown linkage. Install new sealing washers on the fuel line fittings and reconnect the fuel inlet and return lines, tightening securely.
15. 15

    Reinstall air cleaner assembly
    Position the air cleaner base gasket (new or reused if in good condition) onto the fuel meter body. Set the air cleaner base in place and install the 4 mounting bolts, tightening securely. Reconnect the crankcase breather hose. Install the air cleaner lid and secure with the wing nut.

Reassembly

1. Reconnect the negative battery cable.
2. Before starting the engine, turn the ignition key to the ON position (without cranking) for 5 seconds, then OFF. Repeat this cycle 3 times to prime the fuel system and check for leaks at all fuel connections.
3. Inspect all fuel line connections, injector O-rings, and fuel meter gasket area for any signs of fuel seepage.
4. Double-check that all vacuum lines, electrical connections, and throttle linkage are properly connected.

Verification

• Start the engine and allow it to idle. Listen for smooth, even idle with no misfiring or rough running.
• Check fuel pressure at the fuel pressure test port (if equipped) or at the fuel line. Pressure should be 15-20 psi at idle.
• Inspect all fuel connections for leaks while the engine is running. Any fuel seepage requires immediate shutdown and correction.
• Test drive the vehicle to verify proper acceleration, smooth power delivery, and no hesitation or stumbling under load.
• Verify that the check engine light does not illuminate and that all throttle and transmission kickdown linkages operate correctly.
• After test drive, re-inspect all fuel connections with the engine running and hot to confirm no leaks have developed.

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