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.
1991 Audi 100 BaseFACTORY OEM SERVICE PROCEDURE
Cold Start Valve
- Ensure engine coolant temperature is less than 86°F (30°C). Disconnect and ground coil secondary wire at distributor cap. Remove cold start valve from intake manifold with wiring and fuel line connected. Point tip into safe container.
- Crank starter for 10 seconds. Valve should emit cone-shaped spray for time duration allowed by ECU. If there is no fuel spray and fuel pressure is present, test system control. See TESTS W/CODES article in the ENGINE PERFORMANCE Section. Dry tip and check for leaks. Acceptable leakage rate of cold start valve is one drip or less per minute.
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.