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 Acceleration Enrichment
- Ensure coolant temperature is less than 104°F (40°C). Disconnect differential pressure regulator harness connector. See Figure .
- Using Adapter (VW 1315 A/1), connect Multimeter (US 1119) to differential pressure regulator and harness connector. See Figure . Set multimeter to 200-mA DC scale.
- Disconnect oxygen sensor connector. Start engine and let idle. Note multimeter reading. Accelerate engine. Multimeter reading should increase approximately 6 mA during acceleration. If reading does not increase as specified, replace differential pressure regulator.
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.