This procedure addresses a replacement request for the Manifold Absolute Pressure (MAP) sensor on a 1966 Chevrolet Corvette 327ci V8. However, the 1966 Corvette used a carburetor-based fuel system without electronic engine management, so no MAP sensor exists on this vehicle.

Warnings

Preparation

1. Verify that the vehicle has been modified with an aftermarket electronic fuel injection system, as the original 1966 Corvette 327 V8 did not come equipped with a MAP sensor from the factory
2. If an aftermarket EFI system is installed, locate the system's installation manual to identify MAP sensor location and electrical connections

Procedure

1. 1

   Verify System Configuration
   Inspect the engine bay to confirm whether the vehicle retains its original carburetor-based fuel system or has been retrofitted with an aftermarket electronic fuel injection (EFI) system. The original 1966 327 V8 used a single 4-barrel carburetor (Rochester or Holley depending on trim). Note that the mechanical Rochester fuel-injection option for the small block had been discontinued after 1965, and no electronic fuel injection was offered. If the original carburetor system is present, no MAP sensor exists and this repair procedure does not apply.
2. 2

   Identify Aftermarket EFI System (If Applicable)
   If an aftermarket EFI system has been installed, identify the manufacturer and model (common systems include Holley, FiTech, Edelbrock, or MSD Atomic). The MAP sensor location, mounting method, and electrical connector type will vary significantly by system manufacturer. Consult the specific EFI system's service manual for component locations and replacement procedures.
3. 3

   Locate MAP Sensor on Aftermarket System
   On most aftermarket EFI throttle body systems, the MAP sensor is typically integrated into the throttle body assembly itself or mounted remotely on the intake manifold or firewall with a vacuum hose connection. Trace the vacuum lines from the intake manifold to locate the sensor, or follow the wiring harness from the ECU to identify the sensor location.
4. 4

   Disconnect Electrical Connector
   Disconnect the negative battery cable to prevent electrical shorts. Locate the electrical connector on the MAP sensor and release the locking tab or clip, then carefully pull the connector away from the sensor body. Note the connector orientation for reinstallation.
5. 5

   Remove Vacuum Line (If Applicable)
   If the MAP sensor uses a remote vacuum hose connection rather than being integrated into the throttle body, carefully disconnect the vacuum hose from the sensor nipple. Inspect the hose for cracks, hardening, or deterioration and replace if necessary.
6. 6

   Remove MAP Sensor Mounting Fasteners
   Remove the mounting screws or bolts securing the MAP sensor to its bracket or manifold. The fastener count and type will depend on the aftermarket EFI system manufacturer. Carefully remove the sensor from its mounting location.
7. 7

   Install New MAP Sensor
   Position the new MAP sensor in the mounting location, ensuring any vacuum port or electrical connector orientation matches the original installation. Install and hand-tighten the mounting fasteners, then snug them securely without overtightening, as most MAP sensors use plastic housings that can crack under excessive torque.
8. 8

   Reconnect Vacuum and Electrical Connections
   Reconnect the vacuum hose (if applicable) ensuring a secure, airtight connection. Reconnect the electrical connector to the MAP sensor, ensuring the locking tab clicks into place. Reconnect the negative battery cable.
9. 9

   Clear Diagnostic Codes and Test
   If the aftermarket EFI system has diagnostic capability, use the manufacturer's scan tool or procedure to clear any stored fault codes related to the MAP sensor. Start the engine and verify that it runs smoothly without triggering new MAP sensor-related fault codes.

Reassembly

1. Ensure all vacuum connections are secure and airtight to prevent false MAP sensor readings
2. Verify electrical connector is fully seated and locked to prevent intermittent sensor signals

Verification

• Start the engine and verify smooth idle and throttle response
• If the EFI system has a diagnostic interface, confirm no MAP sensor fault codes are present
• Monitor engine performance during a short test drive to confirm proper sensor operation across varying load conditions

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