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.
1989 Audi 80 Base, AutomaticFACTORY OEM SERVICE PROCEDURE
Deceleration Fuel Shut-Off Check (Man. Trans. Only)
- Engine oil temperature must be at minimum of 120°F (50°C). Reconnect wiring to temperature sensor. Start engine and run it at 2000 RPM briefly. Release throttle.
- If intake boot does not visibly contract, disconnect harness plug from deceleration fuel shut-off valve. Attach a voltmeter to harness terminals. Start engine and run it at 2000 RPM briefly. Release throttle.
- If 12 volts are present, ensure vacuum hose is okay and replace deceleration fuel shut-off valve. If 12 volts were not present, check operation and adjustment of throttle switch at idle. If okay, check throttle switch to ECU wiring for open.
- If deceleration fuel shut-off valve still does not operate, connect Dwell Meter (VW 1367) to vehicle. Using Adapter Cable (US 1112) connect Green test lead to OXS system test connector. Set "%" button on duty meter. Disconnect harness connector from deceleration fuel shut-off valve. Using a jumper wire, connect terminal No. 2 to ground.
- If duty meter does not indicate 40%, turn ignition off. Disconnect ECU harness connector. Check for 0.2 ohms in wire between ECU terminal No. 4 and deceleration fuel shut-off valve terminal No. 2. See Figure . If ohms are not as specified, check for an open circuit in wire. If circuit is not open, replace ECU.
Factory Service Tools
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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.