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 MANUALSCHEVROLET1981CITATION 4D HATCHBACK, 2.5L ENG VIN 5, STANDARD TRANSREPAIR AND DIAGNOSISENGINE PERFORMANCEENGINE CONTROL SYSTEMSAIR INJECTION REACTOR SYSTEMTESTINGAIR MANAGEMENT SYSTEM FUNCTIONAL TEST
1981 Chevrolet Citation 4D Hatchback, 2.5L Eng VIN 5, Standard Trans
Air Management System Functional Test
1981 Chevrolet Citation 4D Hatchback, 2.5L Eng VIN 5, Standard TransSECTION Air Management System Functional Test
- Visually inspect all hoses and connectors for leaks and proper connections and repair as necessary. Check that diverter valve does not route air to air cleaner at part throttle, but does route air to air cleaner on quick deceleration or any time vacuum drops below 3 in. Hg.
- If not satisfactory, check divert valve system. Air should be diverted to air cleaner for up to 5 seconds after starting engine, then switch to exhaust ports for about 10-60 seconds until system goes to closed loop operation. At this time, air again diverts to air cleaner.
- Check diverter valve hoses and mounting. If satisfactory, disconnect vacuum hose to main diverter valve diaphragm nipple. Reconnect hose and check for diverter flow for up to 5 seconds. If no divert function, replace diverter valve. If diverter air flows for over 5 seconds, bypass the vacuum delay valve and recheck. If diverter flow is now up to 5 seconds, replace vacuum delay valve. If over 5 seconds, replace diverter valve.
- To check select valve operation, start engine and run at fast idle. Pulsation should be felt in hose to exhaust ports until system goes closed loop, then it should switch to catalytic converter hose.
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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.