external/transfer fuel pump on my RS6 died after 68k miles-any suggestions?

[kday]

The 044 is a beast of a pump. It's also really loud. As I recall, the RS6 fuel pump(s) are modulated so that when not under load they aren't run at full voltage, which mitigates this somewhat. Not sure how that would work with an aftermarket pump though.

Did you check the genuineaudiparts.com for the OEM pump? Probably still expensive, but might be less than your dealer.

Regarding the pump pressure, the pressure varies with flow. I have data showing the 044 pump delivering well over 500 kPa, but that was into a 5 cylinder with smallish injectors.

[ramin]

The 044 is a beast of a pump. It's also really loud. As I recall, the RS6 fuel pump(s) are modulated so that when not under load they aren't run at full voltage, which mitigates this somewhat. Not sure how that would work with an aftermarket pump though.

Did you check the genuineaudiparts.com for the OEM pump? Probably still expensive, but might be less than your dealer.

Regarding the pump pressure, the pressure varies with flow. I have data showing the 044 pump delivering well over 500 kPa, but that was into a 5 cylinder with smallish injectors.

Thanks Kday, I checked genuineaudiparts.com for the OEM pump but they don't have the RS6 in their catalog. I need to pull the pump and remove the protective sleeve to get the part number first. Of course, if you know of an easy way to figure out the part number, I would appreciate knowing how. I just didn't want to deal with the gasoline leak until I have the replacement part, so I left it hooked up to the pipes for now.

Also, does anybody know what pressure the OEM pump puts out? I kind of like the smaller pump from ECS tuning (both price and mounting configuration) but I am not sure if 3 bars would be too much with the original pipes. I called ECS but the guy on the phone was kind of clueless as to how well of a fit this one is for RS6. http://www.ecstuning.com/Audi-RS6--4...nce/ES2189784/

[ramin]

By the way, Kday's point about the variable voltage and resulting pressure is correct. So, the 044 pump would act differently depending on the voltage supply. In the RS6, the harness only feeds the transfer pump about 10V at normal speeds and increases the supply to 12V at start-up (for 1 second) and if the car is under acceleration. So, the Voltage feed to the transfer pump is definitely variable by 2-3 V (it's in the VAG manual and I verified it with a voltmeter to make sure there was no problem with the controller logic feeding the pump).

I did some more searching and JCWhitney has a few inline fuel pumps too that they claim match RS6. But, not knowing the exact OEM part specs/pressure, I am hesitant in trial and error with the fuel supply

[lswing]

Here's the ETKA, think this is the external pump you want. Looked up the price, yikes! Cool how it has a sound absorber shroud.

As a side note, I've been logging my injectors recently, and stock fueling seems to have them at 70% under full load. I upped my fuel under load to 110% and the injectors logged 76%. I have been wondering how much fuel the stock pump can push. Enough to have the injectors 85%?

http://genuineaudiparts.com/parts/in...&siteid=214407

[ramin]

Some more info on the fuel pump, the part number is 4B0906089A (sold by http://www.genuineaudiparts.com for $627, a lot cheaper than the dealer) and VAG manual says minimum of 500 cm3/15s flow which translates into 120 liters/hr.

The lower end billet pump (for up to 500 hp) that ben916 mentioned has the following specs (the 044 is obviously a lot more potent):

Bosch 040 "High-Output" 500 Horsepower-Capable
Flow at 55 PSI: 175 LPH
Flow at 75 PSI: 155 LPH

So, I am not sure if this would be too much pressure for the existing OE piping. Any idea on the upper limit for OE piping? 155 LPH is very close to the minimum of 120 LPH mentioned in the manual.

[ramin]

Thanks Lswing, your link has the same part number as the one I posted a minute after yours

The Bosch 040 (not 044) seems like a decent upgrade because it doesn't suggest any other mods other than the terminals, but I still need some info on whether it will burst the existing pipes at that rate. I am going to look at the pipes again, I think they have a PSI rating on them.

[lswing]

Glad to help Keep us posted on the details, good info! Any idea if the injectors can outpace the stock pump? There is some math that I need to work on....

[Ms_RS6]

The 044 is a beast of a pump. It's also really loud. As I recall, the RS6 fuel pump(s) are modulated so that when not under load they aren't run at full voltage, which mitigates this somewhat. Not sure how that would work with an aftermarket pump though.

Did you check the genuineaudiparts.com for the OEM pump? Probably still expensive, but might be less than your dealer.

Regarding the pump pressure, the pressure varies with flow. I have data showing the 044 pump delivering well over 500 kPa, but that was into a 5 cylinder with smallish injectors.

I do have the 044 Bosch Fuel Pump installed. It is a little loud, specially when you are running low on gas. I haven't had any issues with it. I decided to upgrade it since I was thinking of going with a full stage 4 MTM but was afraid of upgrading turbos since it is really expensive and labor intensive (and I didn't want to mess with anything major unless it was broken . I have Wagners, colder plugs, MTM Exhaust and recently gutted the downpipes. Anyway, I'm not too car technical and wish I could answer more questions about the pump but again, it hasn't given me problems and I have had it installed for more than 20k miles.

[ramin]

I do have the 044 Bosch Fuel Pump installed. It is a little loud, specially when you are running low on gas. I haven't had any issues with it. I decided to upgrade it since I was thinking of going with a full stage 4 MTM but was afraid of upgrading turbos since it is really expensive and labor intensive (and I didn't want to mess with anything major unless it was broken . I have Wagners, colder plugs, MTM Exhaust and recently gutted the downpipes. Anyway, I'm not too car technical and wish I could answer more questions about the pump but again, it hasn't given me problems and I have had it installed for more than 20k miles.

Hi Ms_RS6, thanks for the info. Did you install the 044 in-line outside the tank (there seems to be another similar looking pump that goes on the inside of the tank - the direction from 034motorsport sent by Ben 916 shows the pump installation inside a fuel tank)? If we are talking about the fuel pump that is installed outside the fuel tank, two more questions: (1) does the 044 fit in the old slot for the OE pump? (2) did you end up changing the OE piping?

Incidentally, I found the pressure requirements in the VAG Manual. The pump needs to deliver 0.8 to 1.3 bar to the fuel rail for OE set up.

[Ms_RS6]

Hi Ms_RS6, thanks for the info. Did you install the 044 in-line outside the tank (there seems to be another similar looking pump that goes on the inside of the tank - the direction from 034motorsport sent by Ben 916 shows the pump installation inside a fuel tank)? If we are talking about the fuel pump that is installed outside the fuel tank, two more questions: (1) does the 044 fit in the old slot for the OE pump? (2) did you end up changing the OE piping?

Incidentally, I found the pressure requirements in the VAG Manual. The pump needs to deliver 0.8 to 1.3 bar to the fuel rail for OE set up.

Here's the install and DIY link of when it was done to my car.
http://www.rs6.com/showthread.php/21...sure-regulator

[ramin]

Great, thanks Ms-RS6!

Did you also change the regulator (to a 5 bar one) and flash your ECU? The last comment on the thread you sent V8weight says " It may be kind of hard on the pump however, trying to push all that extra volume through a 4bar regulator."

By the way, found the answer to whether the Bosch 044 pump fits inside the tank. Apparently it does with some modification (not sure what kind/how much modifications though).

[Ms_RS6]

Great, thanks Ms-RS6!

Did you also change the regulator (to a 5 bar one) and flash your ECU? The last comment on the thread you sent V8weight says " It may be kind of hard on the pump however, trying to push all that extra volume through a 4bar regulator."

By the way, found the answer to whether the Bosch 044 pump fits inside the tank. Apparently it does with some modification (not sure what kind/how much modifications though).

I did change the regulator as well to a 5 bar. I also flashed the ECU.


-Maria

[ramin]

Thanks Maria, I am going to some research to see if I can avoid a reflash of the ECU