Standard Ignition AC31 Idle Air Control Valve

Idle Air Control Valve for Ford and Mercury Applications

Standard Ignition AC31 is an idle air control valve built for precise airflow management during changing engine load conditions. It is a direct-fit fuel injection system component for select Ford Mustang, Ford Thunderbird, Mercury Cougar, Ford Taurus, Lincoln Continental, and Mercury Sable applications.

With a 2-terminal blade terminal design and precision-machined internal components, this AC31 idle air control valve helps the ECU regulate idle speed by controlling bypass air as engine demand changes.

Key Features

• Precision-machined housing supports accurate airflow control at idle
• Solenoid components are machined for consistent magnetic actuation of the plunger
• High-temperature polyester coating on the solenoid coil wire supports operation through repeated heat cycles
• 2 terminals with blade terminals for the specified electrical connection
• Built under complete quality control from component manufacturing through finished assembly

Detailed Description

Standard Ignition AC31 is an idle air control valve for vehicles that rely on ECU-managed idle speed control. It is used in fuel injection systems to regulate bypass air when engine load changes, helping maintain stable idle behavior in everyday driving conditions. This part number AC31 is listed for 1994-1995 Ford Mustang, 1988-1995 Ford Thunderbird, 1989-1995 Mercury Cougar, 1989-1991 Ford Taurus, 1989-1991 Lincoln Continental, and 1989-1991 Mercury Sable.

This part cross-references Gates 21763 for the same application.

What It Helps Address

• Unstable or fluctuating idle speed
• Idle speed that drops too low when accessories are turned on
• Idle control issues during warm-up or load changes
• Airflow regulation problems in the throttle body idle circuit
• Replacement needs for a worn or electrically inconsistent idle air control valve

Installation Notes and Tips

Verify the connector style before installation: AC31 uses 2 blade terminals. Confirm the vehicle application by year, make, and model, and compare the original part number and connector layout before replacement. For best results, inspect the throttle body and related intake passages for carbon buildup that can affect idle control performance.

Quality Assurance

Standard Ignition manufactures emission-related components with process control from individual parts through final assembly. The solenoid coil wire uses a high-temperature polyester coating to support reliable function during repeated exposure to elevated engine temperatures.