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.
1994 Audi 90 CS QuattroFACTORY OEM SERVICE PROCEDURE
Main Pump Fuel Volume Check
- Remove fuel pump relay from relay panel. Attach a hose to fuel pump outlet connector and place other end of hose in a graduated container.
- Using a DVOM between fuel pump connector terminals No. 1 (Green/Yellow wire) and No. 4 (Brown wire), measure voltage being applied to fuel pump when activating with Remote Control (VAG 1348/3A). Activate fuel pump for 30 seconds. Record voltage.
- Fuel pump volume is relative to voltage applied to fuel pump. Compare volume with values in FUEL PUMP PERFORMANCE table. If volume is not as specified, replace fuel pump.
FUEL PUMP PERFORMANCE
| Voltage Applied | Min. Vol. In 30 Sec. Pts (L) |
|---|---|
| 10 | 1.0 (.46) |
| 11 | 1.3 (.62) |
| 12 | 1.6 (.75) |
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.