93 Audi 100 S fuel pump questions.

Old 04-28-2011, 08:53 PM
1st Gear
Thread Starter
Join Date: Apr 2011
Posts: 1
Default 93 Audi 100 S fuel pump questions.

1993 Audi 100 S.
165000 miles.
2.8L V6, Automatic.

Last weekend my Audi decided not to start then after 15-20 min it started then after that it hasn't started since. I've researched what it could be and signs point to faulty fuel pump/relay. Fuel filter is good and no fuel is getting to filter at all. I read that relay is located on far right side, under driver dash. It does click on when ignition is turned on for a few secs. To be sure, I manually engaged relay with cover off and still no start.

Now my question is what is the difficulty level of changing the pump on this vehicle? The tank does have to be dropped for this correct? Thanks for any advice!!
Old 05-22-2011, 07:56 PM
1st Gear
Join Date: Nov 2006
Posts: 253

You might've fixed it by now, but hell...

If it's like the 90S then no, you don't have to drop the fuel tank. Removing the pump is fairly easy (on the 90S). It's located under in your trunk, by your spare tire (passenger side). In few words: unscrew the round cap, remove the level sensor and then pull out the pump.

The long explanation (straight out of the Bentley manual):

-Disconnect battery.
-Pull back luggage compartment carpet to expose access cover.
-Remove access cover for fuel level sensor and fuel pump.
-Disconnect the harness connector for fuel level sensor and fuel pump.
-Disconnect both fuel supply lines.
-Loosen and remove collar nut using special tool 3217...or by hand like me
-Remove flange assembly. (Note the mark on the flange matches the one on the fuel tank...install the same way.)
-Disconnect fuel pump and fuel level sensor electrical connections.
-Disconnect fuel supply and return lines from inside of flange assembly.
-Fuel sensor is on the side of the whole assembly. You have to press a clip on its side and lift it out.

-Insert fuel pump wrench 3307 (for fuel pump) through fuel tank opening and place on inner part of surge housing. I forgot what I did that with but it wasn't the tool.
-Rotate inner part of surge housing approx. 15 (to left stop, or counter clockwise) and remove fuel pump.

When removing the pump, there is a mark on the housing you need to pay attention to. There is a notch on the upper part of the surge housing that matches with another mark on the inner part of the housing. Once you turn it 15 degrees, the notch on the housing should match with a second mark. Install in reverse order.

Let me know if you need pictures.
Old 01-24-2012, 06:15 PM
B4_quattro's Avatar
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Join Date: May 2010
Posts: 5

Nice write up. Just did mine and I'm having a problem with collar. Not able to get the flange to sit flush in the tank, and when I put the collar on the flange not stay flush so with a full tank I get fuel overflow. Any ideas
Old 08-10-2014, 05:11 PM
1st Gear
Join Date: Aug 2014
Posts: 3
Default Fuel pump replacement '93 Audi 100 CSQ

I just today replaced the fuel pump in my '93. I did not use the special tool for the retaining ring, I used a flat head screw driver and rubber mallet to accomplish the removal and installation of the ring. I did purchase the special tool for the fuel pump basket removal, but to my dismay the pump is to far forward and the four tabs on the tool can't engage rendering it useless. Now I have to try to return it for a refund. I used a three foot length of pipe and a rubber mallet to turn the basket so I could remove it. The discovery I made in this process is that if you can release the tabs that hold the pump in place, the pump will slide out without removing the basket. Hopefully I won't have to do this again and this can be helpful to someone else.
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