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Audi B5 RS4 | Fitting Bosch 044 Fuel Pump | 10/11/11

After only having the RS4 for a few weeks I pulled up to work one morning and all was fine, jumped into the car at lunchtime and it wouldn't fire. The petrol warning light had just come on when I pulled up that morning, but surely it couldn't be out of fuel. We tried several things to see what might be the cause (VAG-COM, Immobiliser, adding more fuel etc.) but nothing, the last resort was the fuel pump though none of us could figure out why it would go from totally fine when parked up after a drive to total failure the next time it was started.

After taking the original fuel pump out we tested it on the bench, would you believe it the thing seemed to work! It made no sense at all, so we popped it back into the car and tried it again, NOTHING!!! This was so odd, we checked all the wiring from the fuse board to the pump and that seemed fine. We figured it must be some kind of dodgy pump regardless and changing it was the best course of action. Checking out the price of a new OEM pump we figured it was almost the same price to get a Bosch 044 pump (which is rated far higher than the OEM pump) and the necessary basket/filter best suited to fit that pump.

So we ended up with a Bosch 044 pump and the following Audi basket/filter:

Reservoir Upper: 89520177H (£29.16 + VAT as of Jan 2011)
Strainer: 895201531A (£30.39 + VAT as of Jan 2011)

Audi B5 RS4 | Modifying Basket| 16/01/11

The reason for the different basket/filter is that the Bosch 044 pump has a much thicker diameter, making it next to impossible to fit in the original RS4 basket (some have said it can be done, I don't see how). The mods are pretty simple though, essentially it's just cutting a section off the top part of the basket allowing the pump to sit low enough to fit back in the tank.

At first we followed some pictures from someone else’s guide online, however it didn't seem to give us enough drop for the pump so we got more serious and cut a far larger piece of the basket off, that did the trick! The pump pickup was still a good 15mm from the bottom of the basket, and comparing the level of the OEM pump pickup made us look at using something to extend the pickup as low as possible in the basket, without touching it as the internal structure of the basket could impede flow. For this we took a bung that had the right thread and drilled the centre section out to as large as we could comfortably go, then using copper washers as spacers set the bolt to a few mm above the bottom of the basket. Sorted!

Then it's just a case of wiring it up and fitting it back in the car. Happy to say this sorted my problem and also gives some decent headroom for future tuning!