Genuine Audi 90 Fuel Pump

Audi 90 Fuel Pump Parts and Q&A

• Overhaul Kit
  447-906-091-E
  Q: How to check and troubleshoot the fuel pump circuit on Audi 90?

  A:

  Check that the fuse supplying the fuel pump circuit is intact. Disconnect the HT wire from the ignition coil and connect it to earth with a bridging wire. Chock the front wheels, then jack up the rear of the car and support it on axle stands for access to the fuel pump. Operate the starter briefly and check that the fuel pump is heard to be operating; on engines PM and 3A, it will operate as soon as the ignition is switched on. If the fuel pump does not run, remove the fuel pump relay from the relay board and connect a bridging wire from the battery positive terminal to the relay terminal 52 in the board. If the pump now runs, the relay is faulty; if not, check the supply wiring to the fuel pump. If the pump is working but the fuel supply is insufficient, the filter may be blocked. To remove the fuel pump, disconnect the battery negative lead. Unscrew the nuts (where fitted) and disconnect the wiring from the pump. Fit a hose clamp to the fuel supply hose. Position a suitable receptacle beneath the pump to catch spilled fuel, then disconnect the hose and union, plugging the two pipes. Unscrew the nut and release the mounting clamp, then withdraw the pump. If necessary, remove the mounting clamp from the pump. Refitting is a reversal of removal, ensuring that the lug engages with the recess in the clamp.