This actually ended up being a little easier than I thought it'd be. I got an AEM 340 E85 compatible pump and an XS-Power 39mm fuel pump adapter.
The first step (after disconnecting your battery) is to pull the carpet out of your trunk and remove the black cover behind the rear passenger side seat that is secured by 3 screws. This gives you access to your fuel pump. Once the cover is off, mark the direction of flow on your two fuel lines or mark them in a way so that you put them back in the same spot.
Yours will probable have oem single use clamps that you'll have to bust off. Remove the electrical connector and then using a hammer and a flat head screw driver, hammer on the lips on the outer edge of that black cap to turn it counter-clockwise to loosen it. It's not a bad idea to mark the cap so you know how tight to put it back on. Keep hammering it until its loose enough to remove.
Then pull the white fuel pump cover off and you will see some wires and hoses underneath it. The black hose is clipped on so carefully unclip it to remove it. The brown ribbed hose has an OEM single use clamp (if it hasn't been replaced) so be really careful to not cut the fuel line while trying to break that clamp off. Remember which side the wires are on (or use my picture as a reference) and remove the wires. Now the white cap can be removed and set aside. Remove the black or orange tank lid gasket too.
Once that's out, you'll remove the fuel level sender. This has a little tab on the outside of it (the side that faces away from the pump) and you probably wont be able to see it. Feel around for the tab in the picture below and push it in and pull the level sensor up and disconnect its wire.
You'll notice that mine has an aftermarket wire soldered to it. This wire breaks on a lot of B5s and causes the fuel gauge to read inaccurately. Make sure the wire looks good and if it's frayed or broken, solder it or replace it while you're in there. Next use your B5 fuel pump removal tool and seat it in the 4 engagement teeth on the top of the pump... then you only need to turn it counter-clockwise like 10º to unlock the pump. The fuel pump can now be lifted out of the tank.
(what it looks like with the pump removed)
With the fuel pump out you can now unbolt the positive and negative wires on the pump and carefully remove the other single use clamp and ribbed fuel line from the pump.
Also I should mention that I was able to reuse that brown ribbed fuel line on my AEM pump, it fit perfectly. I believe that hose is 8mm or 5/16" so if you do need to replace yours you could probably do so with a fuel-purpose rubber hose.
Back to parting out your fuel pump... the next thing you'll want to do is remove the top cap on your fuel pump housing. I marked mine, you probably don't need to, but why not... You then push in the 4 tabs around the outside of the housing that you see in this picture and then remove the cap.
Then you can pull the fuel pump inner housing out of the large outer cylinder. There will be 6 rubber sleeves in there that seat the inner housing to the outer one.
You now want to remove the plastic support piece/ring that is held onto the inner housing with 6 more rubber sleeves. Remove all these rubber sleeves. Depending on the location, some might be hard to come off so just use a flathead screw driver to pry them off.
This is the furthest point of disassembly, now you'll want to start preparing your new fuel pump. The XS-Power fuel pump bracket is definitely the cheapest one and it works great, but it comes with 2 o-rings and there is no way your fuel pump will fit into the sleeve with those o-rings in there. So throw those o-rings away and slide your new fuel pump into the sleeve. It is important to make sure that your new fuel pump will be sitting in the same position as the old one height-wise so that your car will still keep fueling even when your tank is really low. I compared it to my old pump by doing this in the picture below so that the pickup tube on the bottom would be the same height.
Once the pump position is where you want it, crank that XS-Power sleeve tight and your pump will be locked in there.
With this design you won't need that ring with the extra 6 rubber sleeves, just put 6 of the rubber sleeves you removed onto the XS-Power bracket and drop it right into the big outer cylinder housing. Put the first cap you removed back on and now you have your new fuel pump-in-housing. (You will have 6 leftover rubber sleeves, the original pump design uses 12, this one uses 6).
You can now install the ribbed fuel line onto the aftermarket pump with a hose clamp (my pump came with a new clamp).
*Edit*
I guess AEM fuel pumps don't come with built-in check valves so I installed an in-line check valve with some standard 5/16" fuel line hose right above the outlet of the fuel pump and now the car starts up every time. This is the check valve I used: https://www.highflowfuel.com/i-23908...-8mm-5-16.html. I was having a long cranking issue forever and come to find out, this is what caused it.
Next is the wiring... Audi uses black as the positive/supply wire and brown as the negative/ground wire (it's a weird Audi thing). The AEM pump has red as positive and black as negative. Cut your Audi fuel pump wires at a length that still gives you some slack and solder the black Audi wire to the red new one, and brown Audi to the black new one. Ignore all the electrical tape garbage in the picture below, I changed my harness since I took this picture. Electrical tape will unwrap itself when exposed to fuel so I only used heat shrink wraps on the wires. Also it is a good idea to offset your solder connections incase for whatever reason the connections become exposed down the road. These wires will be sitting in the fuel and if they ever become exposed and contact each other, they will spark and that is bad, bad news.
Now you can connect your "modified" wiring harness in the above picture to the new fuel pump. Then install your sock filter on the bottom of the fuel pump. This is how the AEM one is attached.
Your new fuel pump is now ready to drop back into the tank. This part can be a little tricky because you have to get the 3 (or maybe 4, I can't remember) tabs lined up so you can click it down and then turn it to lock it. These are the tabs in the fuel tank that you need to lock into.
You can see in this picture again that the slots on the pump housing are the ones you see on the very bottom.
You'll want to push the fuel pump in pretty good until you think they've clicked, and then grab your fuel pump tool to turn it 10º clockwise to lock it. Pull up on it to make sure it actually locked in. I had to do this a few times until I seated it correctly and turning it actually locked it. The key is to try and have it go in perfectly straight so all 4 tabs contact at the same time. When it's locked in you'll know because you can pull on it hard and it won't come up. Reinsert the fuel level sender back into its spot, it will click when it locks in. Make sure there are no wires or anything keeping the steel level sender arm and plastic ball from moving all the way up and down. Now reconnect the wires and fuel lines to the upper white fuel tank cap and seal the cap back on the top of the tank with the black or orange lid gasket. Lock that black plastic lock ring by hammering it clockwise until it's tight or lined up with the mark you originally made. Reconnect the electrical connector and fuel lines on top and you are good to go!
It might crank a little extra on the first start to get fuel through the lines, but mine started right up and the AEM pump is super quite! Can't wait to see how the pump performs under load!
Reply With Quote
Originally Posted by Seerlah
Bookmarks