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
Residual Pressure
- Connect Pressure Gauge (VW 1318) as described previously in SYSTEM PRESSURE. See Figure . Open pressure gauge valve.
- Operate fuel pump for at least 30 seconds. Shut off fuel pump. Note system pressure. Pressure should be 51 psi (3.6 kg/cm2 ) after 10 minutes and 49 psi (3.4 kg/cm2 ) after 20 minutes.
NOTE:
RESIDUAL PRESSURE test DOES NOT include cold start valve testing. To check cold start valve, attach fuel line. Operate fuel pump and visually check for leaks.
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.