jonas321

So my wife's 2006 A4 (non-quattro) started acting up a couple of months ago. Intermittent stalling when fuel level at <1/4 tank. Took to dealership and had error code for low fuel pressure. So they replaced the fuel pressure sensor.

Problem recurred next time the fuel level was below 1/4 tank again. Took back. This time error codes were for evap canister purge valve and low fuel pressure. Also fuel pump duty cycle was 62% at idle. They wanted $1000 to replace purge valve, fuel filter and fuel pump.

After a bit of research (on here mostly), I decided to do the work myself.

I first did the evap canister purge valve (super easy), fuel filter (super easy), and the High-pressure fuel pump cam follower (not sure if it had ever been done, 70k on car, moderately easy).

These steps improved the driveability and eliminated the occasional CEL illuminations. I suspect the Purge Valve was the biggest culprit. The fuel pump idle duty cycle dropped to 56%, still above the 50-55% that is recommended.

The only write-ups I saw for the in-tank fuel pump replacement was for the Quattro model. These write-ups all said that the fuel level needs to be as low as possible, and absolutely no more than 1/4 tank. So I waited until the fuel level was at 1/8th tank and then changed the in-tank pump as well.

I took some pics of the process for the Non-Quattro model and thought maybe I'd share it on here. Hopefully someone may find it useful.

Here we go:

As mentioned in other threads, the access panel is in the trunk, on the passenger side. Held in place by 3 phillips head screws.


Removing the screws gives you access to the top of the fuel pump. Make sure you clean all the dirt out. I used compressed air. Removing the electrical and fuel connectors is similar to the Quattro model.


The High Pressure connector is the one at the ~4 o'clock position and it gave me quite a bit of difficulty. Others have said to use a second person to press down on the connector to overcome the residual fuel pressure. I didn't have a second person around. I made a custom "pinch tool" from a cheap pair of needle nose pliers, but that didn't do the trick either. Eventually I just went ahead and released the fuel pressure in the line by disconnecting the back-lower fuel connector on the fuel filter (located just in front of the passenger rear tire). About a cup of fuel spilled out, then the connector was as easy to remove as the low pressure connector.

I bought the special tool to remove the lock ring, and it was easy to use. Would have been even easier if I'd used a 1/2" drive T-handle instead of the 1/2"breaker bar at my disposal, as the breaker bar tended to "rock" the tool out of alignment. I used my other hand to leverage the tool in place, but this was somewhat awkward lying in the back of the trunk.







The fuel pump now lifts up fairly easily. There is a white connector at the 10 o'clock position that needs to be removed before the pump will come out. The tabs pinch together and this releases the connector which is attached to a long black tube. See the pictures below for details. I do not believe this tube is present on the Quattro models.

The replacement pump is slightly different. I'm told the extra tubing is to accomodate the fuel-heating system available on some cold-weather models, and that now all replacement pumps are this way.

YOU MUST BUY THE BLOCK OFF PLUG. This plugs off the extra circuit. It is black and seen installed on the new pump in the picture below.

Also pay attention to the "clocking" of the white adapter on the long black tube. Mine was significantly "off" from the factory one, which led to a WTF moment, until I put them side-by-side and rotated the connector to match, as seen in the picture. Then it installed quite easily.

Now, a word about the fuel level. I think this is another deviation from the Quattro model. There was TONS of space, as demonstrated by me holding a standard screwdriver into the tank, and its tip barely reaching the fuel level. Not exactly sure what the max level would be, but probably OK to try at well above 1/2 tank, maybe even more.





Installing the pump was easy, it slips right in. I put the pump in half-way, then put the accessory tube in. Connected all the appropriate connectors and dropped down to position. I then slipped the new gasket over the pump and secured around the rim of the tank. Slighly cumbersome, as it tends to want to jump out.



Once in place, I had to push the pump down sligtly to keep it seated while the lockring was replaced. No pic of this as I have not yet figured out how to grow a 3rd hand. Connectors re-attached and cover replaced. Car cranked for 1 second longer than usual then fired right up.

Curiously, the fuel level read at 1/4 tank after install, where as it read at the 1/8 tank level before. At fill-up it registered to its normal "a hair under the full mark" level, so I suspect the fuel level float was turned to vertical and resting on the bottom of the tank. It spins freely, so now that it is floating freely, it should go back to horizontal. Hopefully. I'll update the thread if the car starts running out of gas at 1/8 tank. :-)


That's all.

Jonas
07 S8
06 A4 FWD
90 Coupe Quattro
78 VW Scirocco

chapstick

Before the initial start up you should open and close the driver's door a number of times until the fuel cycles less and less. This goes as well for the ignition. Turn halfway and off several times before finally cranking. The cycling of the fuel pumps is audible. Good right up

jonas321

Thanks! Yeah, that is good to mention about priming the fuel system. I did not do that and startup was still very smooth, but maybe I got lucky.