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

[kday]

Changing the regulator will require a reflash, but I don't think you need to do this to change the pump. As long as the new pump has equal or greater flow characteristics, it will work the same as the old one. It might be louder or less efficient, but unless the fuel lines (particularly the return line) are so small that the regulator can't bypass enough fuel to keep the pressure delta at 4 bar, a stronger pump won't be a problem. And in that case you would just run rich, which is by far the less severe error.

That being said, I don't think the cost savings are worth it, unless you are looking for a science project.

[terrytcl]

looks like i'm also getting a bunch of misfire and lean codes -

the only problem is that i have not gotten any of the -

17473 - Fuel Pressure Regulation
P1065 - 008 - Regulation Discrepancy

codes....

do you guys think that my transfer pump is going too?

i also get the
"It went from running fine to hesitation when pressing the accelerator. If you press the pedal, it will act like it's dying, but if you ramp up the speed slowly, it will keep going faster and faster. Interesting, the car runs even with a dead fuel pump."

if the car is warmed up, the car runs fine.... but, the car runs on safe mode in my opnion. no power under a certain load.

IDEAS?

[ramin]

looks like i'm also getting a bunch of misfire and lean codes -

the only problem is that i have not gotten any of the -

17473 - Fuel Pressure Regulation
P1065 - 008 - Regulation Discrepancy

codes....

do you guys think that my transfer pump is going too?

i also get the
"It went from running fine to hesitation when pressing the accelerator. If you press the pedal, it will act like it's dying, but if you ramp up the speed slowly, it will keep going faster and faster. Interesting, the car runs even with a dead fuel pump."

if the car is warmed up, the car runs fine.... but, the car runs on safe mode in my opnion. no power under a certain load.

IDEAS?

My car runs runs fine unless I press the gas pedal. It idles fine when warmed up but still has the same issue when pressing the pedal.

One quick test is take out the fuse (I think 28) and see how if it runs any differently. Mine runs the same when the fuse is out.

A second slightly more difficult test is to unplug the transfer pump and see if it changes the issue. BUT, be super careful as the plug connection is very fragile. Alternatively, you can just check the voltage at the transfer pump without unplugging the wire. If the pump is getting 9-10V and not vibrating, it's not working. The voltage starts at battery level when you start the engine for about 1 sec and then drops to 9.xV until you are under heavy acceleration.

[ramin]

It looks like the experiment has paid off I only replaced the external fuel pump with the Bosch 044 pump that puts out 5 bars instead of the 4 bars by the stock pump. Didn't change the tune, fuel regulator, etc.

The beast runs great. Seems like much less hesitation and smoother than the stock pump before it went out. But the stock pump may have been slowly dying over time.

It's a bit noisier than the stock, but nothing you can really hear over the exhaust tone anyway.

The Bosch pump is a bit thicker but is a bit shorter. I had to get the adapters from the UK (over ebay) which took a while. Got the pump from Amazon, just because of the ease of returning if there were issues.

The wiring was simple (brown wire is negative so goes to the blue plug on the new pump and red/black goes to the red port on the new pump). I used some cut up old bicycle tires to make up the size difference between the stock pump (with its rubber sleeve) in the existing mount.

I had to pay a visit to the local ACE to get some stainless steel nuts and bolts. I ended up changing the bolt and nut on the strap style stock mount because the stock screw had fused with the bolt and I had to cut it off (carefully) with Dremel. I also had to get some stop nuts for the electric connectors on the new pump (one 5mm and one 6mm). The two fuel connectors I got (for each end of the new pump) are made of aircraft aluminum and can be found at:
http://www.ebay.com/itm/150660859718...84.m1497.l2649

http://www.ebay.com/itm/170694342501...84.m1497.l2649

Also, added a couple of zip ties for safety. However, with the plugs at the end and the existing strap mount, the new pump doesn't have that much room to move and fall off any way. I didn't even have to change anything on the fuel hoses either (but don't remember if i had to change anything when I replaced the fuel filter last time).

I think the hardest part was just figuring out what connectors to use and how to tighten the new pump in the old strap. I finished the work at 3 am and forgot to take pictures. I will take pictures and post next time I get the car up on the lift.

I will report back if anything goes wrong, but so far 50 miles have flown by with no issues, just a reminder how much fun these cars are to drive. Having seen the weak connector design on the stock fuel pump (which is basically an L-shaped connector with really thin connectors surrounded by thin plastic), I am glad I moved away from the stock pump, even though it took a while to gather the parts and install.

[lswing]

Glad to hear it, sounds like a good project...pics or it didn't happen

[ramin]

Glad to hear it, sounds like a good project...pics or it didn't happen

Sorry for the delay. I just took pictures of the stock vs. Bosch 044 pump side by side. Looking at the stock pump on the bottom, the gray rubber sleeve on the right slides over the stock pump. The two black plastic sleeves on the left go over the stock pump (with the rubber sleeve) to mount it into the strap that holds the stock pump in place. I just cut up an old bicycle tire and wrapped it around the new pump to make the fit snug in the straps.

I will take pictures of the installed pump next time I get the car on the lift.

I have driven 300 miles so far with no issues/codes. The car is actually much more responsive (indicating that my stock pump must have been going downhill for a period of time).

Take a look at the picture of the broken stock connector on the right (white plastic with super thin connectors embedded). It gives you an idea of how fragile the connectors are relative to the sturdy Bosch connector posts. That was one reason I wanted to give the Bosch pump a try even without changing the fuel pressure valve or recoding the computer. I suspect the stock pump was probably not getting a good connection for a while which burned it out over time.

The responsiveness alone makes the project worth it. The new pump seems a bit noisier if you are standing outside next to it; otherwise, I can't really hear it.

[ramin]

Finally got the car back on the lift. Here are a couple of pictures showing the Bosch fuel pump installed. As you will note, I used a lot of zip ties. Also used a piece of old bicycle tire to make up for the diameter difference between the OEM strap and narrower pump. It almost fits perfectly (length-wise) in the existing cavity formed by the fuel tank and body.

I have driven it 1,800 miles with the Bosch pump (without changing the regulator) and have had no issues whatsoever. In fact, the responsiveness is noticeably better (probably due to the original pump not having been at its tip-top shape due to electrical connector weakness).