external/transfer fuel pump on my RS6 died after 68k miles-any suggestions? [Archive] - RS6.com

ramin

July 19th, 2012, 20:05

Hello All,

This is only the second (non tune) problem after a battery change for me. Otherwise the beast has been running great!

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. To be specific this is the transfer/external fuel pump. The pump in the tank runs fine and vibrates the gas tank.

The culprit seems to be the electric connector. It is a pretty weak design. I will post pictures once I get all the parts off and exchanged. Basically, the connector wires attached to the pump body are encased in a relatively thin plastic casing. The wire is very short too, so if there is any play in the pump, it could cause the connecter body to snap off. In any case, the pump doesn't even run with direct power to it (with the connector totally snapped off), so I am not 100% sure which happened first. I guess a bad/loose connection could eventually kill the pump.

What are your suggestions for changing the transfer fuel pump? I would like to stay OE and away from modifying too much as the pump has worked fine for 68k.

The local dealer wants $840 for a new one. I found ECT Tuning has an after market part for $140 http://www.ecstuning.com/Audi-RS6--4.2T/Engine/Performance/ES2189784/

It looks like the ECT part needs some minor wiring modification, stripping, new connector and mounting.

Also worth mentioning, the screw and nut that held the fuel pump strap in place were fused together and I had to cut off the screw. Pretty weak design there too. The ECT pump comes with two new straps. And, I plan to add a couple of zip ties as backup.

Please let me know if you have any suggestions for getting the OE pump (haven't totally disconnected the pump yet so if you have the part number handy I would appreciate it!) at a more reasonable price, any aftermarket pumps, or experience with the ECT pump.

For the sake of documenting the problem, I got the following 8 fault codes:
8 Faults Found:
17473 - Fuel Pressure Regulation
P1065 - 008 - Regulation Discrepancy
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - - MIL ON
16685 - Cylinder 1
P0301 - 001 - Misfire Detected - MIL ON
16687 - Cylinder 3
P0303 - 001 - Misfire Detected - MIL ON
16686 - Cylinder 2
P0302 - 001 - Misfire Detected - MIL ON
16688 - Cylinder 4
P0304 - 001 - Misfire Detected - MIL ON
17536 - Fuel Trim; Bank 1 (Mult)
P1128 - 001 - System too Lean
17538 - Fuel Trim; Bank 2 (Mult)
P1130 - 001 - System too Lean
Readiness: 0010 1101

ben916

July 19th, 2012, 20:14

uh well, you could upgrade the external fuel pump with the Bosch 044 one, it does require some modification to the wiring harness - but you are looking that way anyway.
If you search on here for threads that do have the 044 Bosch fuel pump (5 bar), you should find it.

or -> http://www.034motorsport.com/fuel-injection-solutions-fuel-pumps-billet-drop-in-fuel-pump-upgrade-kit-audi-applications-p-19543.html not 100% sure this is the one but it gives you an idea.

ramin

July 19th, 2012, 20:30

Thanks I read about that but don't really want to change the piping. By the way, ECT lists the 044 Bosch pump at 3 bars only. Not sure if 044 refers to multiple pumps.

http://www.ecstuning.com/Audi-RS6--4.2T/Engine/Performance/ES514125/

kday

July 20th, 2012, 05:06

ramin

July 20th, 2012, 19:43

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--4.2T/Engine/Performance/ES2189784/

ramin

July 20th, 2012, 19:55

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

July 20th, 2012, 20:26

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/index.cfm?searchText=4B0+906+089+A&make=Audi&action=oePartSearch&siteid=214407

12787

ramin

July 20th, 2012, 20:27

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

July 20th, 2012, 20:32

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

July 20th, 2012, 20:35

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

July 20th, 2012, 21:05

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

July 20th, 2012, 21:41

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

July 20th, 2012, 22:10

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/21391-DIY-Bosch-044-Fuel-Pump-5-bar-fuel-pressure-regulator

ramin

July 20th, 2012, 22:57

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

July 20th, 2012, 23:06

kday

July 21st, 2012, 03:01

ramin

July 21st, 2012, 04:06

No need to worry about bursting the lines. Even if it was possible for the pump to develop that much pressure (it's not), the job of the fuel pressure regulator is to keep that from happening.

I guess if you put an 044 in the tank you could just bypass the external pump entirely.

Yep, kday, you are correct. I think I was misreading the original thread about installing the 044. The issue was raised that if you don't use a "high pressure" hose (i.e., one rated for fuel injection) it may burst. I wasn't thinking at all and that what's there already is fuel injector hose rated at 180 PSI plus.

I found the top flow number in the manual too. It is 600 cm3/15s at 13V (ramping up from the minimum of ~320 cm3/15s at 9V). So the flow range between 9V and 13V (which is controlled by the fuel control module J538) goes from 78 liters/hour (20.6 gal/hr) to 144 liters/hour (38 gal/hr) for the stock set up.

Since 044 Bosch pump requires reflashing the ECU with the 5 bar regulator, I need to first call APR because I have their ECU.

So, I will spend the weekend trying to figure out if I can find a pump that matches the flow of the stock set up to avoid dealing with a reflash.

ramin

July 21st, 2012, 04:07

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

kday

July 21st, 2012, 17:07

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

July 24th, 2012, 20:02

ramin

July 30th, 2012, 02:27

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

August 27th, 2012, 03:39

It looks like the experiment has paid off :rs6kiss: 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?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649

http://www.ebay.com/itm/170694342501?ssPageName=STRK:MEWNX:IT&_trksid=p3984.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

August 27th, 2012, 05:24

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

ramin

September 12th, 2012, 19:48

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.

1293212933

ramin

November 7th, 2012, 01:03

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).

1314613147

lswing

March 1st, 2016, 18:19

Looks like I might go this direction. Dig up some more hardware and mounting brackets and should be good to go.

Edit; looks like the eBay sight below does not ship to US, so looking at this, and just need to find the other end piece. http://autofittings-uk.com/shop/en/bosch-fuel-pump-adapters/348-9mm-bosch-044-fuel-pump-outlet-check-valve-in-billet-aluminium-banjo-adapter-fitting-with-cap-autobahn88-ft163-barb-kit.html

Adapter fittings for fuel lines, http://www.ebay.co.uk/itm/171000801335?ssPageName=STRK%3AMEBIDX%3AIT&fromMakeTrack=true

Bosch 044 from Amazon, http://www.amazon.com/Bosch-61944-Universal-Inline-Fuel/dp/B003WL73OK
(http://www.amazon.com/Bosch-61944-Universal-Inline-Fuel/dp/B003WL73OK)

hahnmgh63

March 2nd, 2016, 05:13

Rock Auto has it for even less.
http://www.rockauto.com/en/parts/bosch,61944,fuel+pump,6256

Bigglezworth

March 2nd, 2016, 14:16

Best deal going hands down and where I purchased a pair from back in January....
http://www.ebay.com/itm/Genuine-Bosch-300lph-044-pump-E85-and-Alcohol-available-180days-quality-warranty-/172044288885?hash=item280ea38375:g:pCgAAOSw5VFWPXy b&vxp=mtr

lswing

March 2nd, 2016, 15:44

Hot damn, good prices there. I've read many articles saying those pumps are commonly knocked off in China, authentic packaging and all. Seller rating looks good though. I suppose if it's a fake one and fails then it's only another hour to swap a new one in.

Edit; you find a NA source for the connectors? I guess they are more common in Europe, seems almost all adapters are sold from over seas.

Edit 2; Never mind, just ordered as bethridg had linked.

http://www.ebay.com/itm/121851679972?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

http://www.ebay.com/itm/151991398523?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Bigglezworth

March 2nd, 2016, 16:20

The 'knock offs' say "Made in Germany". The authentic are stamped "Czech Republic".

lswing

March 2nd, 2016, 19:44

The 'knock offs' say "Made in Germany". The authentic are stamped "Czech Republic".

Pretty sure you've got a knock off there. They say the new China ones also say Czech. Look at the etching/printing on your pump, notice the quality being poor compared to this one below. You should also be missing the blue pen dot, and worse case non-helicoil threading on the insert side. Who knows really, lots of forum articles on these things.

http://www.ebay.com/itm/111920992046

lswing

March 7th, 2016, 23:04

I'll have an Amazon shipped 044 here in a few days. Will report back with pics and authenticity impressions.

So do you use a bit of thread lock or sealant for the adapter pieces that screw into the inlet and outlet?

lswing

March 19th, 2016, 21:24

044 from Amazon, looks legit per some threads and comparisons with the knockoffs. Consensus was you can run a knockoff, but some have failed early. Here are details for a legit pump.

Packaging plastic is crimped Bosch.
17174

Clean printed label, not pixelated, made in Czech.
17175

Crimped area marked with pen. Also note + and - symbols are up at an angle and very clean. Fakes will not have crimp marks and symbols are on the flat part of the top.
17176

Clean stamped, not roughly engraved, also confirms Czech build location.
17177

Big deal here, some fakes do not have the helicoil insert shown, and are also a smaller diameter. This has helicoil insert for strength, and full size for max fuel flow.
17178

Got the wiring, adapters, and fuel line. Going to wire up and have the shop put in next week. Can anyone confirm using a thread-lock or sealant for the adapter threads into the pump?

Fastguy

March 26th, 2016, 14:57

Good link. If mine turns out to be fake I'll grab one from here. First time, in the description, I've seen anyone note "minimum current 12 volts". It's noted in multiple places. Think this matters?

nubcake

March 26th, 2016, 17:10

Good link. If mine turns out to be fake I'll grab one from here. First time, in the description, I've seen anyone note "minimum current 12 volts". It's noted in multiple places. Think this matters?

That's a weird statement in itself, because direct current (DC) is measured in amps: https://en.wikipedia.org/wiki/Electric_current ;)
My bet is that's someone not very intelligent decided to put it in a description and others just copy-pasted it away.
I understand your concern, but I'll repeat myself that I've had a car with fuel controller and a 044. Plus, I know a few others running it without any issues.

And, well, frankly, an ordinary "dumb" fuel pump (which 044 surely is!) should start on voltages as low as couple of volts. It will just flow way less. Which exactly is the reason why audi engineers implemented the whole fuel controller thing. Check out this link (it's the first one google came up with when I tried to find a voltage chart): http://www.enginebasics.com/Engine%20Basics%20Root%20Folder/Fuel%20Pump%20Basics.html

And this picture describes the whole situation pretty accurately: http://www.enginebasics.com/Engine%20Basics%20Root%20Folder/Images/Fuel%20Pump%206.jpg
While you theoretically will get more flow by bypassing the controller, there can be negative consequences: fuel heat-up, noise, spontaneous alternator voltage fluctuations potentially could also result in fuel pressure variation. Bottom line is: do not try to outsmart factory engineers when it's not absolutely necessary. :)

lswing

March 26th, 2016, 17:16

Also, the Extras page in my website has documentation on how the fuel controller works in general. It's the Self Study Guide.

Fastguy

March 27th, 2016, 00:41

Yeah. I've been referring back to that when I was considering running a relay. It's weird (and not that it matters since I going to run the pumps off the controller) but I never did figure out where the controller is actually located. I have a second rs in the garage with no interior and I pulled back the carpet. I don't see it anywhere in those areas. I'm wondering if it's not under the steering wheel with all the connectors and relays.

Ultimately, the logs will tell the story. If I've got enough fuel, great; it's what I need. If not, gotta figure something else out. From what I can tell, this is kinda new territory. I've searched for days and was always led back here to the same few threads. I've got damn near up to 30 psi available and no way to utilize it right now. These turbos are insane. I can't wait to have fueling and boost finally shake hands. It should be a new level of surprising; Like the first time I drove the car with the manual. I had a perma smile. I hope this will be the same. I can drop the clutch now in second and spin the tires at 40-50 mph(dry roads in a straight line). I hope I'll be able to do that after getting fuel to match boost just stepping on it with no clutch. Wet roads will be down right scary for the passengers. :hahahehe: