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
Fuel Pressure Release
CAUTION:
High fuel pressure may be present in fuel lines and component parts. Relieve pressure before opening system for testing or component replacement. DO NOT
allow fuel to flow onto engine or electrical parts.
- Remove fuel pump relay from fuse panel. Start engine. Let engine run until it stops. Turn ignition off. Disconnect negative battery terminal. Install fuel pump relay.
- Use a rag to cover fuel system connection before disconnecting high pressure fuel system component for test or repair procedure. Some residual fuel pressure may still be in system.
Factory Service Tools
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Disclosure: Verified tool recommendations may earn an affiliate commission at no cost to you.
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.