# Electric Fuel Pump Failure (W12): Diagnosis, Mitigation, Pump Replacement



## PanEuropean (Nov 3, 2001)

The primary electric fuel pump in the fuel tank of my 2004 W12 failed last month, shortly after I had set out on a cross-Canada trip from Vancouver Island to Toronto. The whole process of diagnosing and identifying the cause of the problem, mitigating it so that I could continue the trip, and finally replacing the fuel pump was kind of complex, so, here's the write-up.

The problem presented itself as a surging of the engine - a momentary loss of power - at normal highway operating speeds. The onset was progressive, but it didn't take very long - only about 60 miles of driving - from the first little cough of the engine until total failure of the pump. The first indication was failure of the car to maintain speed (while on cruise control) when climbing hills. That progressed to failure to maintain speed on flat surfaces, and finally led to the car coasting to a stop, engine stalled, at the side of the road.

I soon learned that if I floored the accelerator pedal and held it against the floor, the car would cough and burp for a few seconds, then take off like a rocket. So, for the next 40 miles, I coaxed the car into the next city by flooring it, accelerating to about 80 MPH, then coasting until the speed dropped to 20 MPH, and flooring it once again and accelerating to 80 MPH. Fortunately, I was on a remote road with few other cars, and no police.

I checked the fuses for the two fuel pumps - fuses 34 and 35 in panel C (above the left battery), and they were both OK.

The next day, I visited a VW dealer in the Canadian Rocky Mountains, and together with the parts manager and one of the technicians, we looked at the Self-Study Guides (SSGs) for the Phaeton, and looked at wiring diagrams. Eventually, we came to a tentative conclusion that the primary electric fuel pump in the fuel tank had failed. The SSGs stated that the primary electric fuel pump (the pump on the right side of the car) operates all the time, and the secondary electric fuel pump (the pump on the left side of the car) only operates during starting and during 'periods of high demand'. That made sense to us - the car started fine, and worked OK when the accelerator pedal was held to the floor (high demand). It just didn't work worth a darn at any other time... the engine would stall, or, the car would not accelerate at all.

Here are two illustrations taken from the SSGs that describe how the fuel delivery system works. The first image is taken from the 'Phaeton Overview' SSG, which applies to all vehicles. The second image is taken from the W12 engine SSG. I kind of suspect that all the Phaetons operate in the same way, regardless of engine, because the fuel tank in all the Phaetons has the same shape - two lower lobes, which means two pumps are required.

*Descriptions from the SSGs*

I think that there may be an error in the description above. My experience suggests that the right hand pump (identified as G6, above) is the primary pump, and the left hand pump (identified as G23) is the one that switches on during starting and periods of high demand. Note also how the identification of G6 and G23 in the illustration above is reversed from what is shown in the illustration below. I believe that the text and illustration below is correct, and the text and illustration above is incorrect.


The 'effects of failure' in the description above would, I believe, make sense if it was the left-hand pump that failed. In my case, the right hand pump failed, and the effects of failure that I experienced were as I set them out in the beginning paragraphs of this post - quite different from the 'effects of failure' of the left hand pump that are described in the SSG above.

-----------------------------------

After coming to the tentative diagnosis that the primary electric fuel pump (the right hand pump) had failed, we checked the parts stock status in North America. There was one pump in stock, but it was in the United States, and being that it was a Thursday, the pump could not be delivered before the following Tuesday. I didn't want to spend that much time waiting for it, so, we started thinking about other possible solutions.

If we could somehow get the secondary electric fuel pump - the pump on the left side of the car that only operated during starting and heavy demand - to operate, that just might put me back on the road again. So, I removed the plastic cover from the small relay that operates the secondary pump, and wrapped a rubber band around the relay, thus keeping the relay in the closed position. A short test drive proved that this solution worked just fine, the car once again operated normally. The only "problem" was that the last 25% of the fuel in the tank would be unusable, because that fuel would be left behind in the right-hand lobe of the tank - the lobe with the defective primary fuel pump.

*Electric Fuel Pump Relays
*Here is an illustration from the Phaeton wiring diagrams identifying the various relays above the left battery.

Here you can see the two relays for the electric fuel pumps. They are identical part numbers.


Here you can see the relay for the secondary electric fuel pump, with a rubber band wrapped around it to keep it continually closed.


Aside from the loss of use of the last 25% of the fuel in the fuel tank, the car worked just fine with the secondary electric fuel pump running all the time. There were no problems noted even under heavy acceleration. It was, however, necessary to physically remove the rubber-banded relay from its position in the relay panel whenever the car was shut down for more than half a hour. The power to this relay comes from Terminal 30 (battery direct) - it is not switched on and off with the ignition as Terminal 15 power is. This meant that if the rubber-banded relay was left in position overnight, the left hand battery would totally discharge, because the fuel pump would operate continuously all night. I discovered this the morning after the first night...

So, for the next 8 days, I drove across Canada, removing the relay each night and replacing it each morning. I didn't bother to remove it when I stopped for meals or fuel. The rest of the 3,000 mile trip was uneventful - except once, when I let the fuel tank run down a bit too close to the 1/4 full mark, and the car began surging again because the left hand lobe of the fuel tank (with the functional secondary pump) had emptied out. That was a close call, but I managed to get to a gas station and refuel.

After arriving in Toronto, I called the parts staff at my home VW dealer and ordered a new primary electric fuel pump. I discovered that the left and right hand pumps are slightly different (the various hoses coming out of the pumps are different), and I also discovered that a pump costs about $400. The parts staff suggested I order two seals (one for each side of the tank), because I would have to remove both the right and left fuel tank covers to change the right pump. The seals were not expensive.

Here are two pictures that illustrate where the pumps sit in each lobe of the fuel tank. Note the fuel filler port on the left side of the pictures (as we know, it is on the right side of the car) for orientation.

*Phaeton Fuel Tank, showing pumps*




*Fuel Pump Access Panels*
Below is a picture that shows where the access panels to the two fuel pumps are. It's easy to get to these access panels, just remove the carpeted panel from the floor of the trunk.


Here's a close-up of the right side (primary) electric fuel pump access panel.


The instructions (from the VW Repair Manual, or the ELSA / ErWin system) for replacing the fuel pump are quite well written. The repair manual suggests that the fuel tank be drained before replacing a pump. I didn't want to drain the tank, so, I ran the fuel level down as low as I dared (remembering that 1/4 full is effectively 'empty' with a failed primary pump). That proved to be adequate.

There are a heck of a lot of steps involved in disconnecting all the hoses and loosening the various components before the pump can be removed. I strongly suggest that anyone attempting this task have a printed set of instructions before starting disassembly.

The fuel pump has quite a few hoses and connections on it, but fortunately, each connector is unique in design, thus it is not possible to hook things up the wrong way when installing the new pump. It is possible to 'lose' a hose inside the tank... for this reason, I attached a small piece of string to each hose I disconnected from the pump.

The process goes more or less like this:

*1) *Remove the two 404 relays, to ensure no power is sent to either fuel pump.

*2)* Lift the rubber cover, and remove the electrical connections from both pumps (left and right).


*3)* Using a special tool, lift up the three fasteners that hold the cap over top of the access panel (these are NOT threaded fasteners!)


Here is a side view of the three fasteners that hold the plastic cap in place - they are friction fit, not threaded.


*4)* Now you have a clear view of the access panel. It will probably be dusty and rusty, and should be vacuumed clean before proceeding, to prevent crap from falling into the fuel tank when the cap is removed. The rust is due to condensation forming on the cold metal part whenever the car is filled with cold fuel from an underground storage tank.


*5)* A special VW tool is used to remove the locking ring from the access panel. 




*6)* After removing the locking ring, I buffed it up with a wire brush to remove surface corrosion.


*7)* The plastic access cap can now be lifted. There are two electrical connectors on each fuel pump, but three possible fittings on the plastic cap. Fortunately, the three fittings are keyed differently.


*8)* This is what you see inside the tank after removing the plastic cap.


*9)* After following all the detailed instructions for disconnecting and stowing hoses, disconnecting the fuel measurement probe from the pump housing, etc., it is possible to lift the pump out. It will be full of fuel.


*10)* The old and new pumps, side by side. I was very surprised at the amount of crap that was trapped in the filter screen at the bottom of the pump. The car only has 60,000 miles on it, and I have always used premium fuel in it.


*11)* I was also a bit surprised at the discolouration of the pump components. Below you can see the old and new pumps side by side.


*12) *It is necessary to get access to the opposite side (in this case, the left side) fuel pump, because hoses from each pump travel horizontally across the tank and connect to the other pump.


*13)* Here you can see a new hose from the right side pump connecting into a T fitting above the left side pump. It is easy to thread this hose across the top of the inside of the tank.


*14)* As mentioned earlier, there are three possible fittings on the base of each plastic cap, but only two connectors within the fuel tank. Everything is keyed, thus improper assembly is not possible.


Once the new pump has been installed, the hoses connected, and the fuel measuring probe reset into the side of the new pump, re-assembly of everything is quite straightforward. I replaced the rubber ring around the access panel opening on each side of the tank, and I also buffed up the locking rings using a wire brush (to remove corrosion) on each side.

It was not a pleasant job - your hands get covered in fuel, and there are some hazards associated with working on an open fuel tank with vapour escaping, but it is not a particularly difficult job. It is time-consuming, though.

If anyone needs to do this work in the future, the two most important pieces of advice I can offer are* A)* be sure to have the VW special tool for removing and reseating the locking ring, and; *B)* Be sure to have a full set of printed instructions, because there are a lot of little tiny detail steps that need to be done. The description I have provided above kind of over-simplifies the process.

Michael


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## steveskinr (Oct 31, 2007)

Well done.

If you were designing the car, would you try for complete redundancy?


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## PanEuropean (Nov 3, 2001)

No, the cost and complexity would be too great relative to the few failures of this type that could be expected.

The aircraft that I was responsible for had a similar low pressure electric fuel pump system. There were two pumps in each tank, one that was active at all times and a second one that was there as a standby. If the active pump failed (as determined by a drop in pressure measured at the pump output), the standby one would come on automatically. That was a pretty simple system, but it still required pressure switches at the output of both pumps to confirm functionality, as well as a failure detection and changeover system.

In the case of the Phaeton, no great harm comes from a pump failure (meaning, the car won't fall out of the sky) - the car just stops working, that's all.

Michael


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## PowerDubs (Jul 22, 2001)

Excellent post.


I wonder about any longevity effects on the secondary pump. It may not be designed for continuous use.


For example- some appliances have electric drain pumps that are designed with an expected life span measured in days. (less than a month). And that is with a specification for time on / time off to cool down.

Sounds shocking until you realize the pump typically only runs for seconds at a time, totaling a few minutes per cycle. 

If we were to say cumulative 3 minutes a cycle, that allows 20 cycles per hour of lifespan, 480 cycles a day, 14,400 cycles in a 30 day month.


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## PanEuropean (Nov 3, 2001)

PowerDubs said:


> I wonder about any longevity effects on the secondary pump. It may not be designed for continuous use.


The left and right pump are different part numbers - this is due to how the hose connections are formed (length, connector type, etc.) coming out of each pump. But, the actual pump bodies (pump mechanisms) are identical on each side.

Having said that, I want to emphasize that the left and right pumps are NOT interchangeable, because the nature of the hose connections are very different between left and right.

Michael


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## vwgeorge2 (Mar 24, 2008)

steveskinr said:


> Well done.



Agreed...

Well documented and informative post.

Thanks


:beer:


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## Auzivision (Apr 19, 2007)

Hi Michael,

Sorry for your troubles and thankful for your documentation and sharing. 

I like how they designed a way to service these without having to drop the tank, very clever. 

THanks, 

Kurt


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## twgin (Apr 25, 2012)

I just stumbled across this thread, fascinating to me as the symptoms Michael describe are identical to symptoms I experienced driving a Phaeton from Indiana to California back in mid 2013. I described my experience here:

http://forums.vwvortex.com/showthread.php?6089137

After reading this I realize that I was doing the same thing, speeding up and slowing down, flooring the accelerator and hence activating the secondary fuel pump. It was a terrible time, I felt like I was beating my new Phaeton to death and I was certainly the most erratic driver on the road that day.

In my case the problem largely went away with the installation of a new fuel filter, and progressively went away the further west I got. Since getting the car to California it has never exhibited those symptoms again; I have put over 10,000 miles on the car since that time. I eventually came to believe that I got some real bad gas in Little Rock, AR which exacerbated effects from a very old fuel filter. Who knows ?

Great fix with rubber banding the relay.


Terry


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## twgin (Apr 25, 2012)

Michael, in the process of looking at lean fuel trim codes the pump(s) come under suspicion. Having looked at a removed pump, could debris in the entry screen be a cause of poor pump output ? Several people including me have changed fuel filters and noticed a lot of gunk in them; I wonder if fouled intakes on the pumps are a problem.

Thanks,

Terry


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## PanEuropean (Nov 3, 2001)

twgin said:


> ...could debris in the entry screen be a cause of poor pump output ? Several people including me have changed fuel filters and noticed a lot of gunk in them; I wonder if fouled intakes on the pumps are a problem.


Hi Terry:

It's possible. In theory, the thought you put forward (above) is credible. On the other hand, the bottom of the pump is submerged in fuel, the screen on the pump would have to be really, really plugged up badly in order to interfere with fuel flow. Also, consider that when the fuel tank is full, there is quite a bit of fuel above the pump (hence a fair amount of 'head pressure'), the weight of the fuel above the pump would assist in forcing fuel through filters, etc. into the pump body.

It is a difficult job to get access to the pump to inspect the screen on the bottom. Due to the hazards involved (fuel vapours, etc.) and the need for special tools, I don't think I would recommend investigating the pumps unless every other possible cause had been ruled out. I think that the most effective way of proving or disproving your theory would be to buy a spare relay for the second pump (the left-hand pump, the one that only comes on during starting or heavy acceleration) and rubber-band the relay as I did, this to make the second pump work all the time. Then drive the car and see if anything changes.

Be aware that if the fuel pump relay is 'rubber-banded', it will run 24 hours a day, ignition on or not, this means you have to physically remove the modified relay whenever you turn off the car, otherwise the battery will go flat.

But, if I was starting diagnostics from scratch, I would change the fuel filter under the body of the car first, before investigating the fuel pumps themselves. There was also a post made in the last month by another forum member who found that some rubber fuel hoses in the engine area had perished and were collapsing (under vacuum) when the engine was hot and had heated the hoses up... I would investigate that before looking at fuel pumps in the tank.

Michael


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## Bindaham (Apr 4, 2014)

PanEuropean said:


> There are a heck of a lot of steps involved in disconnecting all the hoses and loosening the various components before the pump can be removed. I strongly suggest that anyone attempting this task have a printed set of instructions before starting disassembly.


Hi Michael,

Any chance you could post the instructions?

Regards,

Salah


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## Bindaham (Apr 4, 2014)

Update:

I did the rubber band trick on the secondary fuel pump relay and drove the car for miles without a problem so I figured the main pump is the culprit of all the problems that I had lately.

Went ahead and acquired a new pump which to my surprise was available. When I got home I noticed that there was an expiry date on the box and that was Oct. 12 of this year! I usually check the expiration date on milk cartons not on fuel pumps :facepalm:

It doesn't smell though 

I wonder if I shall act blind and go ahead and hook it up


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## Gabs08PHTN (Jan 6, 2011)

Hi Salah,
If I was you, I would return it straight away to avoid later :banghead:, just in case... 
I would think that if there is a due date is because there are some components that might age and become useless with time.

Gabriel


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## Bindaham (Apr 4, 2014)

Hello Gabriel,

That might be true otherwise why put an expiration date on the pump! We'll see tomorrow.

Regards,

Salah


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## Bindaham (Apr 4, 2014)

I just took out my main fuel pump, filthy like hell



What's worse is that I kept having broken wires all over due to the age of the pump and everything associated with it. Here's the guage sender with broken wires that will be soldered with fresh wires



The plug wires are in bad shape



Will report after all is done on the performance with the makeshift stuff.

Regards,

Salah


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## invisiblewave (Sep 22, 2008)

Interesting project! How hard was it to get the thing out?


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## Bindaham (Apr 4, 2014)

Not an easy task due to the location be it at the end of the trunk. Managable though with occasional use of foul language :laugh:

Will report shortly on the result at test driving.


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## Bindaham (Apr 4, 2014)

After few initial stalls after the pump work was done, happy to report that the car is driving well.

What a relief


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## Bindaham (Apr 4, 2014)

Any one has the part number for the fasteners?


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## Bindaham (Apr 4, 2014)

After a prolonged search I think it's 701867299 but I'm not sure


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## invisiblewave (Sep 22, 2008)

Salah, while you were in there, did you come across anything that deals with the fuel level? My fuel gauge sticks at just over 3/4 full.


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## Bindaham (Apr 4, 2014)

Yes indeed. I believe it's the gauge sender (second pic in my post 15 above). 

There are two of those in there, next to each pump. The pic was for the one attached to the main pump (right side - passenger side)

There's a good discussion on the same issue as yours here


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## invisiblewave (Sep 22, 2008)

Thanks, I don't recall reading that thread before. Mine started off intermittent as well, but now appears to be permanent. I did report it to the dealer while it was still under warranty but they didn't do anything about it. It's not a huge inconvenience, so I'll wait until the fuel pump fails before I replace it! If you haven't already reassembled everything, it might be worth you changing it.


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## Bindaham (Apr 4, 2014)

I agree with you. I did finish the job but the good thing is that changing the sender will be a breez in comparison with changin the pump for there's no hoses attached to the sender.


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## invisiblewave (Sep 22, 2008)

Is it fairly easy to get the sender out then?


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## Bindaham (Apr 4, 2014)

Much easier than getting the pump, that's for sure


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## Bindaham (Apr 4, 2014)

After two days of smooth sailing, last night I had the loss of power while at highway speed come back again! Few times! Then smooth sailing after fill up with ultra gas (98). (Usually fill 95)

Scanned today (no loss of power through out two scan.

First scan got this interesting results:

-------------------------------------------------------------------------------
Address 01: Engine Labels: 4D0-907-560-BGH.lbl
Part No SW: 4D0 907 560 CR HW: 8E0 907 560 
Component: 4.2L V8/5V A 0020 
Coding: 0026873
Shop #: WSC 79301 793 79399
VCID: 78FFE4180810F6DEA37-5140

6 Faults Found:
17538 - Fuel Trim; Bank 2 (Mult) 
P1130 - 001 - System too Lean - Intermittent
17536 - Fuel Trim; Bank 1 (Mult) 
P1128 - 001 - System too Lean - Intermittent
18666 - Oxygen (Lambda) Sensor B2 S1 
P2234 - 004 - Signal Shorted to Heater Circuit - Intermittent
18663 - Oxygen (Lambda) Sensor B1 S1 
P2231 - 004 - Signal Shorted to Heater Circuit - Intermittent
18847 - Oxygen (Lambda) Sensor B2 S1 Voltage too Low / Air Leakage / Sample Error 
P2415 - 008 - - Intermittent
18846 - Oxygen (Lambda) Sensor B1 S1 Voltage too Low / Air Leakage / Sample Error 
P2414 - 008 - - Intermittent
Readiness: 0000 

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 3D0-920-xxx-17.lbl
Part No: 3D0 920 881 Q
Component: KOMBIINSTRUMENT RB4 0421 
Coding: 0005121
Shop #: WSC 79301 793 90315
VCID: 3467102854F8D2BE4FF-5140

4 Faults Found:
00771 - Fuel Level Sensor (G) 
010 - Open or Short to Plus - Intermittent
00438 - Fuel Supply Sensor 2 (G169) 
010 - Open or Short to Plus - Intermittent
00439 - Fuel Supply Sensor 3 (G237) 
010 - Open or Short to Plus - Intermittent
00251 - Fuel Supply Sensor 4 (G393) 
010 - Open or Short to Plus - Intermittent

-------------------------------------------------------------------------------

Erased the faults and drove around the block, scanned again and pooof, no faults in the aforementioned addresses!


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## invisiblewave (Sep 22, 2008)

Have you changed the fuel filter?


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## Bindaham (Apr 4, 2014)

I did, last October


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## twgin (Apr 25, 2012)

I am unfortunately all too familiar with P1128 and P1130 codes. These are long term fuel trim codes; they might not show up until the engine is under heavy load. On my car these codes were preventing me from passing smog (California). I finally did pass smog by resetting all codes before taking about a 15 mile loop with very gentle acceleration and no speed over 50 mph; during my 15 mile loop no codes were generated, so I took the car in and got it past the smog test. One day later with normal driving including freeway on ramp accelerations, the codes are back and the CEL on. Oh well, I've got two years until the next smog check to complete fixing the problem ! Anyway, in your case your drive around the block might not have been enough to trigger the codes, they might come back next time at higher engine loads ...

It is possible the rest of the codes are resultant from the fuel trim; on my car excessive fuel trims prevented the Catalytic Convertor and the Secondary Air System from ever passing Readiness checks. Fixing the fuel trims got rid of other problems. Having said that your car generated an impressive list of codes ! Can't see how fuel trims would generate O2 sensor and fuel supply sensor codes, but stranger things have happened with the Phaetons.

Measuring block 032 on the Vag Com to look at short term (idle) and long term (under load) fuel trims (four cells, 1st is short term bank 1, 2nd is long term bank 1, 3rd is short term bank 2 and 4th is long term bank 2). Ideal values would be dithering +/- around zero. I believe that if long term fuel trims go above +15% you will get the P1128 and P1130 codes. Since you get both of these (one for bank 1 and one for bank 2) your problem is not specific to one side of the engine or the other but rather the entire system. Positive fuel trims mean System is lean, either too much air (an air leak) or too little fuel in the final mixure in the cylinders.

Reading the thread I couldn't tell what your original problems was; was it the fuel pump cut out symptoms that Michael describes in the original post ?


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## twgin (Apr 25, 2012)

Also, in your photo, the intake screen on the old pump looks black ! Was it filled with crap that would have impeded pump flow ? I had the fuel pressure check on my car, which was OK, but I always suspected that a clogged intake screen might diminish volume, curious as to your opinion on this having looked at one ...


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## Bindaham (Apr 4, 2014)

Hello Terry,

Thanks for your input. My initial problem was exactly the fuel pump cut out symptoms that Michael described. I changed the pump and fixed few bad wirings and the car started but initially had engine shut offs few times while idling. Then, when driving for miles it was ok. To make it short, in two days after the pump job, I drove it under all kinds of driving modes (City, Highway) and all was well. Then the symptoms came back, then went away!

After that scan that I posted, I drove it for at least a 100 Miles in all driving modes, perfect!

The fuel pump that I replaced was the original one made in 10/2003, it was filthy like there's no tomorrow. I am putting 98 octane gas from now on.

Will moniter and report. 

Regards,

Salah


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## Muhhin (May 3, 2015)

*Just remove the primary's fuel pump relay to get working secondary fuel pump instead of primary*

Hi, 
I found that if you just remove the primary's fuel pump relay, then secondary fuel pump starts working right instead of primary fuel pump, and you do not need to modify any relay at all.


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## Bindaham (Apr 4, 2014)

Hi Muhhin,

Interesting! 

Wouldn't that negate the "relay" concept!

Regards,

Salah


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## invisiblewave (Sep 22, 2008)

Very nice discovery!


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## MeinKraft (Oct 17, 2015)

*Fuel Pump Replacement*

Top notch post. I just had to replace my fuel pump in a 2004 Phaeton V8 and this post was this perfect guide. Less that an hour start to finish provided you have the tool to remove the fuel cap. You could probably get off the ring to access the fuel pump with a hammer and chisel but the tool can be purchased on eBay for $35. I would advise getting the tool. Thanks very much for your tutorial!


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## invisiblewave (Sep 22, 2008)

Do you have a link to the tool? I looked and couldn't find the right one.


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## nhdoc (Jun 18, 2010)

invisiblewave said:


> Do you have a link to the tool? I looked and couldn't find the right one.


The manual says the tool is PN T10202, that ought to be what you need to find one online.


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## Rausche (Jul 5, 2016)

Can somebody verify correlation for the P/Ns for 'primary' and 'secondary' pumps described in this thread?

From the parts catalog I have "3D0-919-087-N; FUEL PUMP PHAETON; LEFT" and "3D0-919-087-L; FUEL PUMP PHAETON; RIGHT".

Is it possible that somebody can translate 'LEFT/RIGHT' into 'DRIVER SIDE/PASSENGER SIDE'? I'm never totally sure how parts catalogs determine LEFT/RIGHT (looking from front of car or from back of car) and I want to be sure that I order the correct part.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Rausche said:


> Can somebody verify correlation for the P/Ns for 'primary' and 'secondary' pumps described in this thread?
> 
> From the parts catalog I have "3D0-919-087-N; FUEL PUMP PHAETON; LEFT" and "3D0-919-087-L; FUEL PUMP PHAETON; RIGHT".
> 
> Is it possible that somebody can translate 'LEFT/RIGHT' into 'DRIVER SIDE/PASSENGER SIDE'? I'm never totally sure how parts catalogs determine LEFT/RIGHT (looking from front of car or from back of car) and I want to be sure that I order the correct part.



Left and right are as the driver sits in the car. (Or if you stand behind it looking forward.) It's the same on military aircraft and probably on civilian aircraft. In North America and Europe, the driver sits on the left. (Left Hand Drive or LHD)

It seems that in most island nations the drivers sit on the right. UK, Australia, New Zealand, Japan, etc... (Right Hand Drive or RHD.)

-Eric


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Rausche said:


> Can somebody verify correlation for the P/Ns for 'primary' and 'secondary' pumps described in this thread?
> 
> From the parts catalog I have "3D0-919-087-N; FUEL PUMP PHAETON; LEFT" and "3D0-919-087-L; FUEL PUMP PHAETON; RIGHT".
> 
> Is it possible that somebody can translate 'LEFT/RIGHT' into 'DRIVER SIDE/PASSENGER SIDE'? I'm never totally sure how parts catalogs determine LEFT/RIGHT (looking from front of car or from back of car) and I want to be sure that I order the correct part.


I don't remember which is primary and which is secondary. I'd have to re-read this thread from the beginning and maybe consult the Bentley manual to make sure. I have spent way too much money on the wrong parts lately. 

What parts manual are you using? The VW online manual? 

Do have a Bentley manual and VCDS? 

Is your Phaeton showing a fault?

-Eric


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## Rausche (Jul 5, 2016)

53PL-50AAA-VW611BAN said:


> I don't remember which is primary and which is secondary. I'd have to re-read this thread from the beginning and maybe consult the Bentley manual to make sure. I have spent way too much money on the wrong parts lately.


I'm fairly confident from looking at the graphics in this post that the Driver's side is the primary pump.



53PL-50AAA-VW611BAN said:


> What parts manual are you using? The VW online manual?


Just digging through VW Parts Vortex, they seem to have decent pricing and availability vs. my local dealers.



53PL-50AAA-VW611BAN said:


> Do have a Bentley manual and VCDS?
> 
> Is your Phaeton showing a fault?


No manual, no VCDS (on my Xmas list though!), just getting P/Ns and pricing together for budgeting. The intermittent surging I experience fits the description of failing fuel pump in this thread almost perfectly -- doesn't hurt to be prepared.

I'm not sure if it's showing a fault or not -- I have not had a chance to have it scanned again since doing my primary battery swap. I'll certainly be getting that done before purchasing anything.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Rausche said:


> I'm fairly confident from looking at the graphics in this post that the Driver's side is the primary pump.
> 
> 
> 
> ...



OK, one more question: Have you tried removing the primary fuel pump relay to see if the surging stops?

-Eric

Edit: You might try these guys also: http://www.vwpartsoutlet.com/


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## Bindaham (Apr 4, 2014)

Rausche said:


> I'm fairly confident from looking at the graphics in this post that the Driver's side is the primary pump.


Actually, the passenger side pump is the *main* one (*Right - 3D0919087L*), and the drive's side is the *secondary* pump (*Left - 3D0919087M*).

Regards,


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## Bindabam (Apr 4, 2014)

I got a new password and a new member name!


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## Ncpitman (Apr 19, 2014)

I just went through my fuel pump issue. I had just filled up my car and was on the way home when it died going 75. Long story short, I was able to let it sit for about 30 mins and then make it the mile back home as it died in the driveway. I immediately knew it was the fuel pump so I did what was said, to pull the primary relay in order to drive the car to drain the tank some. Word of caution, I expected the equalizer pumps to keep the levels the same on the left and right. That wasn't the case because I ran out of gas just below a half a tank. I also decided I didn't want to tackle replacing the fuel pump even though it seems straight forward. I didn't want to breath in all the fumes. So I took it to the dealer where they replaced the primary pump. Guess what, same exact issue was occurring with the new pump. So after confirming the relay and nothing else was wrong, we made the decision to replace the left pump. That fixed it. 

So word of caution, I'm not very convinced of the description of how the fuel pumps and transfer pumps work. Obviously without the relay in for the primary and the fact when the mechanic opened the tank, the primary side was full, the driver side pump was working without any noticeable performance. The one thing we couldn't explain is why would the secondary pump work and just replacing the passenger side not fix my problem? The mechanic said his watched the power switch on to the primary pump and then switch off after a few seconds. This was after replacing the pump. Anyway, one mechanic did say it's recommended to replace both pumps when one fails. 

Cheers!

Earl


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## invisiblewave (Sep 22, 2008)

So there's no good way to determine which one has failed? What did they charge you?


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## Ncpitman (Apr 19, 2014)

Just over $1100 for both and a free loaner car for a few days while they ordered the second pump.


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## invisiblewave (Sep 22, 2008)

Ouch! I'll be doing mine myself in that case. The pumps are about $300 if I remember correctly.


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## steveskinr (Oct 31, 2007)

Thank you Muhhin for post 33.

My son did what you suggested and pulled the relay. Kept it above half full for a month, then changed both pumps.

I'm replacing both pumps on my wife's car before there is a failure.


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## Phaetonlvr (Feb 26, 2013)

Just finished replacing the RH fuel pump on my W12 and here's two key points that haven't been mentioned in detail in this thread. First, the secondary (LH) fuel pump will run dry at just under the half full mark on the fuel gauge ... I tried it out. Second the fuel hose that crosses over from the RH pump to the LH pump and that is part of the RH pump is zip tied in the center of the tank and cannot be pulled out. I had to cut the hose at the RH pump and then pull it out the LH side access hole contrary to what the Bentley instructions say. There is a small note at the beginning of the instructions about the zip tie but there is no way to access and cut the zip tie.


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## Phaetonlvr (Feb 26, 2013)

Also wanted to mention that the original fuel pump is made by VDO and I bought a replacement VDO pump for about $202 at FCP Euro instead of the original VW pump for about $361. Once I had the old one out I compared it to the new VDO pump and it's identical and the original was indeed made by VDO so no need to waste money on the VW branded part.


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## 53PL-50AAA-VW611BAN (Feb 10, 2015)

Phaetonlvr said:


> Also wanted to mention that the original fuel pump is made by VDO and I bought a replacement VDO pump for about $202 at FCP Euro instead of the original VW pump for about $361. Once I had the old one out I compared it to the new VDO pump and it's identical and the original was indeed made by VDO so no need to waste money on the VW branded part.


That's good to know. A few years ago FCP Euro had them for sale so I bought them. It wasn't until later that I learned that they were not "correct" Phaeton pumps. They are in my stash but was anticipating having to go to the dealer when the time came. It's good to know they will work.


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