Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMERCURY1991TRACER BASE, 4D SEDAN, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 5 (ENGINE CONTROLS - SYSTEM/COMPONENT TESTS - EEC-IV)EMISSION SYSTEMS & SUB-SYSTEMSAIR INJECTIONAIR SUPPLY CONTROL VALVE
1991 Mercury Tracer Base, 4D Sedan, Automatic
Air Supply Control Valve
1991 Mercury Tracer Base, 4D Sedan, AutomaticSECTION Air Supply Control Valve
WARNING: This page does not describe the selected car, but rather 15 other vehicles, including the 1993 Mercury Tracer, 1993 Mercury Topaz, 1993 Mercury Sable, 1993 Mercury Grand Marquis, and 1993 Mercury Cougar. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect air supply hose at inlet. Accelerate engine speed to 1500 RPM, and verify presence of airflow in hose. Reconnect air supply hose to valve inlet.
- Disconnect air supply hoses at outlets "A" and "B". See Fig 1. Remove vacuum line at vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "B" with little or no airflow at outlet "A".
- Attach a hose from manifold vacuum fitting to air supply control valve vacuum nipple. Accelerate engine speed to 1500 RPM. Airflow should be heard and felt at outlet "A" with little or no airflow at outlet "B".
- If valve does not meet above conditions, replace valve. If airflow operates as described in steps 1)-3), valve is okay. Reinstall hoses and clamps.
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.