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
Deceleration Fuel Shutoff
- Warm engine to normal operating temperature. Disconnect differential pressure regulator harness connector. 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. Accelerate engine above 3000 RPM. Release throttle and note reading on multimeter.
- Reading should decrease to about -50 mA, with throttle closed, until engine speed reaches 1200 RPM. If reading is not as specified, check differential pressure regulator wiring and connectors. If wiring and connectors are good, 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.