If your engine is having trouble receiving the fuel it needs to run properly (and you’ve eliminated the fuel filter as a potential source of the problem), or if you’ve upgraded the potential power output of your engine significantly and simply need to send more fuel from your tank to the engine, then this project is for you. It will show you how to replace the in-tank fuel pump.
As manufacturers changed from carburetors to fuel injection a few decades back, cars shifted to high-pressure fuel pumps and away from the low-pressure, engine-mounted type of pump that you might have had on your carbed small-block back in the day.
The A4 has a high-pressure, in-tank pump with a supply line and a return line, which was de rigueur for cars of the 1990s and early 2000s (more recent cars often do away with the return line). These are pretty reliable devices and rarely have to be replaced. But they can fail, and as mentioned, high-horsepower cars may need an upgraded pump to supply the amount of fuel that they need. If you find yourself in either situation, follow the steps below to learn more about your fuel pump and how to get at it.
sheet metal plate beneath the trunk floor carpet on the passenger side provides the access point for the fuel pump. It is secured with three Phillips-head screws.
Beneath the access plate is the opening for the fuel tank. Dust and dirt from the road below has worked its way to the top of the fuel tank to coat the lid. Use a vacuum or otherwise clean the debris so that it doesn’t fall into the tank.
With the dust cleared away you get a better look at the lid of the tank, the two fuel lines, and the electrical connector for the pump and the fuel level sender. Note the orientation of the lid, which is slightly different for the Quattro and front-wheel drive versions of the car.
Arrows embossed on the white plastic leading in and out through the tank lid indicate the direction of the fuel flow to and from the fuel pump below. Mark the send and return lines so you can reconnect them correctly at the end of the job.
The lid is held in place by the black, knurled outer ring, which tightens down conventionally (righty-tighty, lefty-loosey). It’s hard to turn the ring by hand
- place a block against one of the raised segments of the lid and tap the block with a hammer to get the ring to rotate counter-clockwise.
Run the bare end of the hose down into the tank. This shot gives a good luck at the feed and return lines on the underside of the lid, as well as the two separate electrical connectors for the fuel pump and the fuel level gauge.
Peer down into the fuel tank and you can see the top of the fuel pump. Take note of its alignment, as you’ll have to put the new pump back in the same way. With your gloved hand, reach into the tank and grasp the pump, using those V-shaped bumps to get a grip on it with your fingers. Turn it firmly about 1/8 of a turn counter-clockwise and you will be able to lift it straight up.
With the pump out of the tank, detach the two wires and the fuel feed hose and transfer them to your new pump. Now is the time to remove and replace the old rubber fuel tank seal, as you will want to pass the hoses and wiring through the seal.
Looking down into the tank with the fuel pump removed, you can see the well into which the fuel pump is installed, as well as the float-and-arm assembly that rises and falls with the fuel level inside the tank. The two tan hoses both attach to the fuel-return side of the lid; they need to be tucked inside the tank to make room to remove and reinstall the fuel pump assembly.
Lower the new fuel pump assembly down into the tank. Maneuver it into the fuel pump well and make sure to lock it into place, turning it 1/8 turn clockwise to secure it. Recover the fuel return lines and electrical wires from the inside of the tank and reattach them to the underside of the fuel tank lid.
Reinstalling the lid is simply the reverse of the removal. Make sure to reinstall the fuel lines to the correct sides of the lid and then use new hose clamps or zip ties to secure the lines. Reattach the electrical connector, tuck any slack wire or hose under the edge of the trunk floor, and reinstall the
sheet metal cover with its three Phillips-head screws.
Comments: Thank you awesome posts. I have 2001 Audi A4. Cat drives fine but stalls from time to time. Throws no codes and you just have to restart it. It seems to be dieing out more and more. Also taking more attempt to get it started. Tried best fuel but still happening. Already replaced the litter fuel pressure valve thing under the hood but no luck. Next thought is filter. Can a fuel pump be "sometimes working" or is it something that if it is out, the would not even start?
July 28, 2014
Comments: I need help and where to find the problem, I have the audi a4 2003 and find out winshield pray not working, I clean the hose on both side is clear, but when i push wiper only headlight spray working, anyone know where to look into this problem??please help..thank you
July 5, 2014
Followup from the Pelican Staff: The washer pump could be faulty. I would start there. - Nick at Pelican Parts
Comments: The fuel pump in my 1997 A4 Quattro looks different, I Have the 2.8 V6! Is it almost the same thing to take out the bottom part? Twist it??
June 27, 2014
Followup from the Pelican Staff: It should be the same. This tech article applies to your vehicle:
Audi A4 (1997-01)
Audi TT (2000-04)
VW Passat (1996-00)
VW Golf (2000-02)
VW Jetta (2000-02)
VW Beetle (1999-02) - Nick at Pelican Parts
Comments: Hi i have problem with my audi a4 1996 model when i start it it doesnt start it just only give me a warning light of oil and i changed it already with the filter as well.will it be the lightning coil or fuel pump？
May 27, 2014
Followup from the Pelican Staff: The oil light is likely as a bulb check when starting. It normally goes out once the engine starts. I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and pressure fuel, volume and quality. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
Comments: **200 rpms**
May 12, 2014
Followup from the Pelican Staff: got it, thanks. - Nick at Pelican Parts
Comments: My b5 passat has idle problems and wont keep itself under power any more than 2000 rpms.. It's chunky when it moves and stalls often. throwing code p1545, could this be my problem, I have a friend who had the same problem with his Jetta
May 12, 2014
Followup from the Pelican Staff: That fault usually ends up being from a faulty throttle control module. - Nick at Pelican Parts
Comments: Had a bad camshaft sensor and the fuel pump was also bad. But I didnt have normal rubber hoses like in your picture, I had brittle smaller ones with a plastic connector.
April 23, 2014
Followup from the Pelican Staff: Thanks for the additional info. We appreciate it.
- Nick at Pelican Parts
Comments: Confirmed the original fuel pump was not working, replaced it and the filter, on my Jetta 1.8 still won't start, any suggestions?
March 22, 2014
Followup from the Pelican Staff: I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and pressure fuel, volume and quality. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
Comments: I just recently had the fuel pump/fuel filter replaced on my 2005 Audi A4 1.8t and now there's not whooshing air pressure sound or air being released when I open the fuel cap when buying gas. Also my car is now getting 10mpg less from 34 to 24mpg on the highway, and my dash gauges no longer work correctly. This was done at the dealership and they are refusing to accept that these issues are from their botched fuel pump replacement that I paid $1100 for. Any advice?
February 3, 2014
Followup from the Pelican Staff: The vent hose for the fuel tank may be plugged. I would start there. - Nick at Pelican Parts
Check out some other sample projects
from the book: