2005 BEW PD lift pump operation and internals

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
If you end up needing new IN TANK fuel hose, look on this page, then scroll down a fair bit. You can find the corrugated hoses (my favorite) or you can get the solid elastomer (rubber looking) hoses.

I have personally seen hoses turn to mush when put into fuel tanks - just fuel rated hose will not work.

http://apeusa.com/html/kits.html

Edit: The "no-suffix pump" with the white canister, external hose to the eductor and blue/grey top plate is now the only pump available from any source, vendor or dealer. See post #26, #57 and #70 for comparison photos.

I got to examine and test an aftermarket lift pump (1J0 919 050 with no suffix letter) as sold by the vendors on the site today (12/19/2008), and I now DO now recommend it for PD's, I no longer recommend doing Left Coast resident's suction modification to these pumps. The modified suction lines were failing much more often than the pumps themselves. Though the idea of the mod is sound, the execution causes problems.

Edit: Skip to post #7 for some simple tests for your PD fuel system.

Edit: November 2011 replacement pump and motor is now available for the original pumps, this means you can now just replace the bad part, for less money, and do not need to buy the new model pump and modify it. http://forums.tdiclub.com/showthread.php?t=336104&highlight=Lift+pump

I took my PD lift pump out and apart today, I was intending to install LCR's alternate suction path
http://forums.tdiclub.com/showthread.php?t=208968
, to ensure my tandem pump could get a suction if the lift pump failed.
I was also searching for any failure modes of this assembly that could cause elevated fuel temperatures, when you have a known good fuel thermal tee and fuel temperature sensor.

I found that I did not need to do the mod; my pump assembly is not even close to the one that LCR pictured, and I can pull fuel from the assembly even with the pump completely failed. Enough fuel to limp home, for sure, if I do not have any air leaks occur when I start pulling a vacuum on the usually pressurized lines.

My pump is part number
1J0 919 050 B, Built out of POM in FRANCE, with a Pierburg electric pump inside it.
and as far as I can tell it is the original pump for the car, which was built in 4/2005.

MY lift pump flows .85 gallons per minute, or 3.2 liters per minute. This is flow to the fuel filter; the electric pump actually flows more, but some is used in the eductor.

This flow rate is enough to equal the cam driven pump's potential flow (which is 1.3 lpm per 903 rpm) at 2200 rpm, but not higher. Above 2200 rpm flow through the fuel rail will be essentially constant, as the positive displacement tandem pump will be limited in flow to that supplied - it will have voids inside the pump. (As the tandem pump draws a vacuum on the lift pump assembly's discharge it will rob a slight bit from the eductor, not enough to matter to the fuel rail, but enough to impact the eductor performance.) The fuel rail will be held at about 15 psi by the outlet pressure regulator - so your injectors will never see any voids.

This may help explain why fuel temperatures tend to run over 70 C at speeds of over 65 mph or so. Below 65 my car will hold 70 C unless the fuel tank is near empty.

The shut-off head of my lift pump was about 15 psi - using a 150 psi gauge, so the reading was not too accurate. It did solidly peg my 10 psi gauge.

Pump assembly overview:
[/IMG]

The pump sits in a canister with a fairly open top structure, and only one small check valve on the very bottom to allow fuel to enter the canister. There are no other openings below the top of the canister.

This photo shows the top of the pump (black round circle with red and black wires to it), you can see the discharge hose going back into the canister. You can also see the pump discharge hose coming back up out of the canister.
[/IMG]


The normal fuel flow path is fairly complex. The only way to get fuel out of the tank (when level is below about half) is for it to pass through a rough screen, then through a check valve, through an eductor, and into the canister main body where the pump sits. The pump has a fine metal screen (grounded) on its suction. The pump discharge is sent out the top of the pump, through a discharge line, back into the canister body to drive the eductor. There is also a pump pressure control valve (spring loaded valve) on this line, that will relieve into the canister if a low flow/high discharge pressure condition occurs. The remaining flow (normal flow path) is directed to the exit of the pump assembly, where it passes through another spring loaded check valve, to prevent return flow to the tank in this line.

[/IMG]


This photo shows the pump discharge hose coming in from the left and entering the tee where it feeds the pump overpressure control valve (white cylindrical object just below the pump discharge hose), and the eductor (not much to see of the eductor from this view, it just looks like the base clipped to the canister.)
[/IMG]

Under the suction screen on the outside of the canister, you can see the inlet check valve. All fuel that leaves the tank passes through this check valve. You can see the rounded casting for the eductor to the right of the check valve.
[/IMG]

The return line (from the tandem pump, thermal tee, and fuel to air heat exchanger) goes into a path that is dumped right at the top of the canister. This return flow is 1.3 liters per minute at idle. During normal operation the eductor pulls in more fuel than is discharged to the fuel filter. This causes a continuous overflow out the top of the canister, carrying the warm fuel from the return line out the top, and ensuring a steady supply of cooler fuel from the fuel tank.

When the tank level gets so low that the eductor is pulling air instead of fuel, the return flow from the tandem pump will fall into the canister, ensuring a pump suction until it runs completely dry.

If the pump quits running, the tandemp pump (or a mityvac) can pull fuel up through the eductor jet (reverse of normal flow). This hole is small, but would provide enough fuel to get home at low power levels. I doubt it could support full power operation. The tiny opening would be subject to plugging if you had debris or gel in your tank.
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
2005 BEW PD lift pump internals

This is the rough suction screen on the bottom outside of the canister. The canister inlet check valve is hidden behind this. The screen is shown loose in its mount.
[/IMG]

This shows the canister inlet check valve and the eductor body from inside the canister. The tee with the overpressure control valve has been removed to make this visible.
[/IMG]

This shows the jet for the eductor and the top half of the eductor body. This small hole provides the suction path for the tandem pump if the electric pump fails.
[/IMG]

This is another view of the eductor jet. The overpressure control valve is just above it. The horizontal black hose is from the electric pump's discharge line. The vertical black hose at the top goes up and out of the canister to the outlet connection on top of the assembly.
[/IMG]
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
If you end up needing new IN TANK fuel hose, look on this page, then scroll down a fair bit. You can find the corrugated hoses (my favorite) or you can get the solid elastomer (rubber looking) hoses.

I have personally seen hoses turn to mush when put into fuel tanks - just fuel rated hose will not work.

http://apeusa.com/html/kits.html

This shows the fine suction screen on the bottom of the electric pump, which sits inside the canister.
[/IMG]

This shows the pump assembly sitting in a test bucket. Note that the fuel level is well below the top of the canister. When the pump was set into the bucket, the fuel levels equalized - only about 2 inches of fuel in the bottom of the canister. When the pump was turned on the eductor filled the canister to overflowing within about 30 seconds. You can see that I have a jumper hose to return the fuel to the return line.
[/IMG]

This shows the full canister, and the fuel pouring out of the return line. The return line (vertical column inside the coil spring) empties at the top of the canister. Fuel is also pouring out of the opening at the bottom right of the photo. The test bucket was not quite level.
[/IMG]

The outlet line from the pump is closed off, so there is no flow out of the discharge line, and no flow into the return line. The eductor is still causing the canister to overflow.
[/IMG]
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
PD lift pump operation high fuel temperature loss of suction at 1/4 tank

The eductor serves to pull fuel from the tank, which is typically cooler than the return line fuel. The warm return line fuel is dumped at the top of the canister, and overflows out the top. The electric pump screen sees the cooler flow pulled in by the eductor. This serves to keep you from recycling mostly the same warm fuel.

I surmise that some folks that are having high fuel temperatures (well over the desired 70 degrees) are suffering from a clogged eductor jet pump, which results in the only cool fuel being pulled into the canister is that flow rate actually consumed by the engine. The recycled warm fuel is just warmed further each cycle.

The ECU sees the high fuel temperatures and retards timing, impacting performance.

This is a thread where we are looking for the source of high fuel temperatures.
http://forums.tdiclub.com/showthread.php?t=225230

A clogged eductor jet pump will also likely cause you to have problems when your tank level is low. Several folks have posted about losing suction at 1/4 tank. This could explain it.
DanG
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Disassembly and Reassembly notes

You would like to have the tank level as low as possible, to minimize the mess.
If tank level is 3/4 or more, it will likely spill out into your back seat.
The tank access port is under the back right passenger's seat.
[/IMG]

The hoses have a spring loaded clip on them that is very difficult to see. Use a bright light and good glasses or a magnifiying glass if you have difficulty. The clip is on the side of the connection directly opposite the hose, and is pushed in with a finger nail or small screwdriver. Push down on the connection, push in on the clip, then gently pull up on the connection. It should come off with very little force.
[/IMG]
[/IMG]

There is a special tool you can buy for removing the large black plastic ring, but I have been successful using a brass punch and hammer, going from ear to ear around the ring and driving the ring around. Do not just beat on one ear.

Note the alignment marks on the ring and pump assembly; mark the ring at the arrow that points toward the back of the vehicle. They must end up with the same orientation. You can barely see the alignment marks in this photo, they are on screen left, which is aft. Orange dabs on the arrow on top of the pump, and on the ring.
[/IMG]

I used a plastic sheet, with the only open area right at the tank opening, to cover my right back seat carpet. The plastic was taped around the rim of the body opening, and was very beneficial. It caught about an ounce of diesel fuel that I would otherwise have smelled for the next few years. Unfortunately I did not get a photo.

The next time I do this (and I expect to do this on two other cars within the next month) I will use a large Mityvac (like a Pella oil extractor) to vacuum the fuel out of the canister prior to lifting it all the way out of the tank. This should reduce the spillage considerably - but I will still use a plastic sheet.

The gasket tends to try to stay in the opening, but it must come up with the assembly; the cannister cannot fit through it.
This ends the removal section.

Start of disassembly (you can skip this section if you are just putting in a new pump. You might want to read post #70):
The electric wires must be disconnected from the underside of the top plate. These are bare metal locking female connections. You have to pull gently downward while inserting a pin through the hole on the male tab to disengage the locking feature. You can see the holes in the two center spades on this photo. The pin (I used a very, very tiny hex key) would be inserted from the opposite side from what you see here.
[/IMG]


You must have replacement hoses ready - you cannot pull the internals out without destroying the original hoses (at least I had to cut mine off.) For replacement hose I initially used Left Coast Resident's recommended 1/4" ID kit hose (one of which later split on a barb) The barbs the hose fit over were .411" at the widest part, except for the electric pump outlet which was .374". It was very difficult to get the 1/4" ID hose over the barb. 5/16 ID hose will work better, either the 1/16th inch or the 1.8th inch wall thickness will work fine. This hose is somewhat delicate - you cannot use pliers or other tools on it without tearing it. So the recommended hose for the "B" variant pump is McMaster.com's 5119K891 (Same as 5119K89) for the 1/8" wall thickness,
or 5119K881(Same as 5119K88) for the 1/16th wall thickness
(both are high temperature FIRM VITON, 5/16" (0.3125") ID. I tried them both, and prefer the thicker one - but either will work fine.)

I also recommend the 5/16" viton hose from dudadiesel; it seems to resist kinking better. http://www.dudadiesel.com/viton.php?...ng_id=17:18:US

This ends the disassembly section.


Installing a lift pump:
For reinstallation you must insert the canister into the tank, then place the gasket properly into the opening by hand before inserting the top plate. The gasket is flexible enough to stretch over the top of the old pump, then stretched over the new pump loosely so that it can be attached to the lining on the tank as the new pump is carefully lowered into place. The lower, canister portion of the new pump first must fit through the tank opening, then the gasket is set in place, and finally the rest of the new pump is set in place. Make sure the arrow on the top plate points directly aft. The assembly is spring loaded, to push the suction assembly firmly to the bottom of the tank, where short standoffs maintain the desired clearance. This causes the top to spring up when initiallly installed.

I used a thin film of silicon grease on the sealing ring threads and the top of the gasket, to make it easier to knock the ring back around. Tighten it until the marks align again.


tips:
Additionally: Cold plastic breaks very easily. Warm up the top of the fuel assembly with a hair dryer or heat gun until it is warm to the touch before you try to pound, pull or disconnect anything.

Many people screw up the orientation. Note the arrow on the top that points to the rear of the car. Make sure it is in the same place when you are done.

Also push lightly in on the new fuel level sender contacts - the ones that move through an arc with the float - and cycle the float up and down 10 times or more. You are just trying to make sure that the clear coat is off of the pickup arc in all places. If there is any left it will cause erratic fuel level indication.

If your tank is really full be very careful when opening the tank. I try to have less than half, and have never opened one with MORE than 3/4. Several other people have and say that if you are a gallon or two down from a normally filled tank (no ventectomy, unvented tank) that it is doable.

If you beat on the bottom of the tank, with your hand or fist, an old failing pump will often run again for a few minutes, this is handy for emergency operation, moving the car, and pumping out fuel to get the level down.
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
2004 PD BEW fuel system components

Dirty fuel screen on the electric fuel pump. This car had been running a bit high on fuel temperature. We thought that perhaps there was a problem in the fuel pickup assembly, causing a reduction of flow.

[/IMG]

Note that this fuel screen is caved in right at the pump suction point, the 2005 done earlier did not display this caved in area. This car's fuel screen was fairly clogged with what appeared to be mainly biologics, though there was a few threads and some flat thin flakes of biologics, too. Again this was thought to be an indication it might have low flow. And in fact this pump showed lower flow than expected when we were pumping out the tank.
[/IMG]

This is the screen after cleaning.

[/IMG]

The screen cleaned up nicely. This seemed to lower the fuel temperatures on the affected car from 93 C down to about 78 degrees C when running at 80 mph.
 
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DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Testing your PD fuel system

our pump can sound like its running and still not be supplying fuel.





In-Tank Lift Pump:
  1. Take off the supply line from the fuel canister to the tandem pump. Put it in a jar. Cycle your key to ON, not start, a couple of times. Your pump should pump 50-100 CC per key cycle. (if you are starting with an empty fuel filter, cycle the key about 6 times before expecting fuel.) Reinstall the line.
  2. If you don't get fuel, check the supply line from the pump to the filter, put it in a jar and repeat the test. Reinstall the line when done. If your filter is plugged, get a new one.
  3. If you don't get fuel, check power to your pump. If you can hear it run, it has power. If you cannot hear it run you will need to test with a light or voltmeter across pins 1 = positive, near squared end of plug, 4 = negative, near rounded end of plug. You should see the light or read 12 volts for a second or two during each cycle of the key. This plug is located beneath a black rounded triangle underneath the carpet beneath your left rear passenger seat.
  4. If your pump has power and is not flowing, and your fuel has not gelled, the pump is likely bad, and needs replaced. There have been one or two cases of reversed fuel lines, and it is possible to plug a line, but I have not heard of any plugging issues. I live in a warm climate and know very little about gelled fuel - consult your local experts.
Testing the Cam Driven Tandem Pump:
  1. This assumes the in-tank lift pump is working; please note that this is a basic test, one that can be done cheaply and easily. When combined with the high pressure test in the Bentley, it is pretty conclusive. Pull the line from the engine head that returns fuel to the thermo tee on the fuel filter. This is the line that looks as if it comes out of the bottom of the tandem pump. It has the fuel temperature sensor in it. Put this line in a calibrated container ( I use a large plastic disposable drink glass, marked off in cups with a black marker.) Start your engine, and a stop watch. You are looking for about 1.3 liters per minute at idle speed. If you get this, then your tandem pump is working and the internal screen is at least somewhat clean.
  2. The high pressure test in the Bentley checks another dimension of the tandem pump - its output pressure at higher RPM. If you are having high speed performance issues that make you suspect fuel delivery issues, you need to get some special fittings (the banjo bolt and one end of an old ALH/BEW turbo oil line fit nicely) and do that test. Otherwise, the first tandem pump test should cover most situations.

    PD FUEL SYSTEM CHECK PDF

    a good additional post for pictures: http://forums.tdiclub.com/showpost.php?p=4935831&postcount=4

Buying a new pump.
How do you choose which pump to buy? (Though it seems a moot point now; only the grey top no suffix pump is available.)
EDIT UPDATE: The TDIWagonGuy is now selling replacement pump units for the OEM assembly - the tan one.

The aftermarket No-Suffix letter pump assembly, as delivered, does a fine job - as long as the electric pump runs. This design does not have the ability to allow your tandem pump to pull fuel from the tank if it quits. It is as good as the stock pump, or better, edit - I recommend using the new pump with no mods.

The OEM 'B' suffix pump as pictured in post #1 above is able, as delivered, to allow the tandem pump to pull fuel from the tank if the electric pump quits.

For the OEM 'B' suffix pump to allow the tandem pump to pull fuel from the tank, you have to have an air tight fuel system. Any air leaks, and just like an ALH with air leaks, either your car will not run, or it will run very poorly.
 
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gforce1108

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Aug 2, 2006
Location
Newburgh, NY
TDI
04 Jetta GLS BEW, 03 Jetta Wagon ALH
Very good information. I've been meaning to pull the seat and inspect my lift pump for over a year, mostly because I've never heard it make a sound in the 2 1/2 years I've owned it. The car runs and drives great so there's been no incentive to dig into it other than curiosity. I guess I have a good reason now to check what part number is in there.
 

aNUT

Vendor , w/Business number
Joined
Nov 29, 2006
Location
Front Range, Colorado
TDI
'01 TT (ALH-ish), B7 Audi gasser
Very interesting with excellent documentation. Were you able to confirm a clogged jet on your friend's problem car?

I also like to add that if excessive fuel temps are detected, it's a good idea to investigate this even if you're not concerned with the loss of efficiency.

Though I've never seen any fuel temp related issues in a PD TDI, the last of the Cummings 24V Dodges before the CR engines replaced them had injection pump failures caused by under performing lift pumps. These pumps simply overheated when they lacked cool fuel. A fuel temp gauge on these trucks is common with enthusiast owners because of this very problem.
 
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DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
aNUT said:
Very interesting with excellent documentation. Were you able to confirm a clogged jet on your friend's problem car?

I also like to add that if excessive fuel temps are detected, it's a good idea to investigate this even if you're not concerned with the loss of efficiency.

Though I've never seen any fuel temp related issues in a PD TDI, the last of the Cummings 24V Dodges before the CR engines replaced them had injection pump failures caused by under performing lift pumps. These pumps simply overheated when they lacked cool fuel. A fuel temp gauge on these trucks is common with enthusiast owners because of this very problem.
aNUT, thanks for the compliment.

Jim's (Nukeskywalker's) car presently has a full fuel tank. He is going to have to burn it down before we will open his and check for this problem. My car, shown here, had no problem.

At work we generally assume that a ten degree F rise in temperature above design halves the working life of the components. Jim is seeing up to 23 degrees C, or 40 degrees F rise over design temperature.

It has to be hard on the injectors as well as the lift pump and tandem pump.

DanG
 

DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
gforce1108 said:
Very good information. I've been meaning to pull the seat and inspect my lift pump for over a year, mostly because I've never heard it make a sound in the 2 1/2 years I've owned it. The car runs and drives great so there's been no incentive to dig into it other than curiosity. I guess I have a good reason now to check what part number is in there.
If you turn on your key with the right rear seat off you will almost certainly be able to hear it, if it is indeed running. If you also have the black metal cover removed the sound level at least doubles. So check its operation while you check for the part number.

DanG
 

DPM

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Newtownards, N. Ireland
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2019 Rav4 AWD Hybrid, Citroen C4 BlueHDI
And as I had a failure of the actual pump in the Grand Vitara (diesel, and using a Bosch supply pump) here's a pic of the pumping mechanism and the failure mode of the unit- a commutator worn clean down to the insulator. And yes, the carbons were OK.
Pump was still in PERFECT condition, no wear to rollers, rotor or stator.


 

DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
DPM said:
And as I had a failure of the actual pump in the Grand Vitara (diesel, and using a Bosch supply pump) here's a pic of the pumping mechanism and the failure mode of the unit- a commutator worn clean down to the insulator. And yes, the carbons were OK.
Pump was still in PERFECT condition, no wear to rollers, rotor or stator.
DPM, thanks for the pictures. I have never seen a commutator get that bad without wearing out the carbon brushes. That must be some soft copper and some hard carbon brushes.

Dan
 

DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
I added a rough sketch of the fuel system in post #1. This may help folks understand the description and the photos.

If there is a draftsman among us who will make this more legible, please email me a copy and I will update the post.

DanG
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Cleaned another assembly on 2004 BEW

Dirty fuel screen on the electric fuel pump. This car had been running a bit high on fuel temperature. We thought that perhaps there was a problem in the fuel pickup assembly, causing a reduction of flow.

[/IMG]

Note that this fuel screen is caved in right at the pump suction point, the 2005 done earlier did not display this caved in area. This car's fuel screen was fairly clogged with what appeared to be mainly biologics, though there was a few threads and some flat thin flakes of biologics, too. Again this was thought to be an indication it might have low flow. And in fact this pump showed lower flow than expected when we were pumping out the tank.
[/IMG]

This is the screen after cleaning.

[/IMG]

The screen cleaned up nicely. This seemed to lower the fuel temperatures on the affected car from 93 C down to about 78 degrees C when running at 80 mph.
 

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
We used a toothbrush and electric parts/brake parts cleaner. Then rinsed quickly in diesel fuel. This was on the screen after it was removed from the pump. We did not want to get any in the pump itself.

Dan
 

DanG144

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Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Viton line failure

My car was having trouble starting today. It took 12 seconds of cranking, instead of 1 second, so I knew something was wrong. I was down to about 1/4 tank indicated, 670 miles. I could hear the lift pump run, but was not able to get any fuel to flow.

The line from the electric pump discharge to the TEE inside the canister had split open in the severely stretched area on the barbed fitting inside the canister. Remember how tight it was? A .25" ID hose was stretched over a .411" barb. It is also possible that the split started at a burr on the plastic barb - a burr resulting from cutting off the original hose. I smoothed the burr out with my finger nail.

I cut the hose shorter and reinstalled it. Then went in and ordered some new hoses from McMaster-Carr. I will post the proper hose sizes for the 'B' variant of the lift pump, after I try several out.
 

DanG144

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Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
fuel line recommendation for lift pump 1J0 919 050 B

So the recommended hose for the "B" variant pump is McMaster.com's 5119K891 (Same as 5119K89) for the 1/8" wall thickness,
or 5119K881(Same as 5119K88) for the 1/16th wall thickness
(both are high temperature FIRM VITON, 5/16" (0.3125") ID. I tried them both, and prefer the thicker one - but either will work fine.

You need one 5.25" long hose, and one 8" long piece for each pump.

I updated the previous post.

MY lift pump flows .85 gallons per minute, or 3.2 liters per minute. This is flow to the fuel filter; the electric pump actually flows more, but some is used in the eductor.

This flow rate is enough to equal the cam driven pump's potential flow (which is 1.3 lpm per 903 rpm) at 2200 rpm, but not higher. Above 2200 rpm flow through the fuel rail will be essentially constant, as the positive displacement tandem pump will be limited in flow to that supplied - it will have voids inside the pump. (As the tandem pump draws a vacuum on the lift pump assembly's discharge it will rob a slight bit from the eductor, not enough to matter to the fuel rail, but enough to impact the eductor performance.) The fuel rail will be held at about 15 psi by the outlet pressure regulator - so your injectors will never see any voids.

This may help explain why fuel temperatures tend to run over 70 C at speeds of over 65 mph or so. Below 65 my car will hold 70 C unless the fuel tank is near empty.

The shut-off head of my lift pump was about 15 psi - using a 150 psi gauge, so the reading was not too accurate. It did solidly peg my 10 psi gauge.

Dan
 

andreigbs

Veteran Member
Joined
Sep 27, 2004
Location
Walworth Co., Wisconsin
TDI
N/A
Many thanks for the detailed write-up and pics that accompany this messy project. I'm sure I may end up having to do the filter cleaning thing and replace a few fuel lines while i'm in there. Keep in mind, I'm on the original lift pump and it's never been "tampered" with. This should be a sticky for PD owners though, nice job.
 

mctdi

Veteran Member
Joined
Dec 10, 2004
Location
se WI
TDI
2010 Jetta
Thanks DanG144 for the write-up. It was a great help with the pictures. As I replaced my 2004 Golf's fuel pump last night. The car has been running rough for a little over a month, mostly when cold. Fuel temps were over 80'C at 70 MPH. Checked things out this week - volt age at pump connector with car running, but no current load through pump, fuel pressure at filter inlet was 5 in.Hg [vacuum].

I used a three jaw gear-puller to turn the big nut off and back on.

Picture added 11/12/08:


Car runs much better now. Fuel temp. now runs 71'C at 70 MPH, and lower at lower speeds.
 
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DanG144

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Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
Yes,
If you have no air leaks in your fuel lines, our PD's can run with no fuel pump. But that tiny hole in the eductor jet is not going to supply much fuel.

Thanks for the data on the vacuum.

Dan
 

Hatchet Ratchet

Veteran Member
Joined
Nov 6, 2006
Location
Freedom, WI
TDI
2004 Jetta PD
so i finally got my pump tore down last night. thanks dan for mcmaster part #'s & good pics, they helped. a helpful hit is to use a dental/o-ring pick for the tab on the eductor housing to reach in and lift off on the tab for removal.

now i'm confused. i took the pump out of the assembly, and wired it battery direct w/ short leads. and the pump runs.

i reassembled, after cleaning screens and pump assy' w/ electronics cleaner spray & toothbrush, w/ new viton hoses, no failsafe fuel mod yet. wired direct in pail of diesel ran pump w/ fuel out to fuel return hose jumper.

it worked and flowed then i cut power, tried again, heard pump whirring, but no flow. i don't know if i just had the leads backwards to the battery or if the checkvalve on the assembly cap was stuck. i removed the spring and checkvalve assy, ran and didn't flow, then removed hose from pump to eductor tee/elbow and reconnected power and achieved flow. reassembled w/ all hoses to their correct path and reassembled check valve & spring in top portion of pump assy', reconnected power, and achieved flow.

will return to project this evening, verify check valve isn't stuck by powering up a few times, then will re-assemble in tank.

will wire hot to battery and hope for flow from output of fuel filter.

verified that the pump wiring connector does get voltage when ignition is turned.
 

Hatchet Ratchet

Veteran Member
Joined
Nov 6, 2006
Location
Freedom, WI
TDI
2004 Jetta PD
failsafe fuel pickup mod

for the series B pump you'll see that there isn't the convient hole for the extra viton hose(w/ check valve) to get to the lower part of the pump assy' like LeftCoastResident did on his alternate model lift pump.

am wondering if this is necessary to do this mod or if drilling a hole in the top of the lower part of the pump assy's cap would be the route to go.

two pump styles below for side by side reference

pic from Left Coast Resident's post http://forums.tdiclub.com/showthread.php?t=208968

Pic from DanG144 this post
 

mctdi

Veteran Member
Joined
Dec 10, 2004
Location
se WI
TDI
2010 Jetta
Hatchet Ratchet said:
for the series B pump you'll see that there isn't the convient hole for the extra viton hose(w/ check valve) to get to the lower part of the pump assy' like LeftCoastResident did on his alternate model lift pump.

am wondering if this is necessary to do this mod or if drilling a hole in the top of the lower part of the pump assy's cap would be the route to go.
My car was running for at least a month, with a non-running ele. pump.
 
Last edited:

DanG144

Top Post Dawg
Joined
Aug 2, 2007
Location
Chapin, South Carolina, USA
TDI
2005 A4 Jetta 5spd
I agree that there is no need to modify the "B" variant pump to allow the car to run with the electric pump failed.

Your tandem pump just takes a suction from the eductor jet nozzle. Your car will act like an ALH - if it has no air in-leakage to your fuel system it will run.

Your fuel temperatures would be higher than you would like - but it would run and get you home. Some folks may not even notice that it has failed.

Dan
 

PharoahTDI

Veteran Member
Joined
Apr 7, 2004
Location
Alliston, ON
TDI
None
DanG144 said:
I agree that there is no need to modify the "B" variant pump to allow the car to run with the electric pump failed.

Your tandem pump just takes a suction from the eductor jet nozzle. Your car will act like an ALH - if it has no air in-leakage to your fuel system it will run.

Your fuel temperatures would be higher than you would like - but it would run and get you home. Some folks may not even notice that it has failed.

Dan
This is true. I took the supposed bad "B" pump in my 04 Jetta and put it in my 00 Golf. I was able to drive the Golf with no power to the pump. It took me a week or so to get the needed wiring parts.
 

DieselCG

Veteran Member
Joined
May 23, 2007
Location
Alameda, CA
TDI
2004 Jetta Wagon 5spd
I'm trying to diagnose a hard starting problem on my 04 (only when the engine is warm or outside temps are above 60ish). Though I'm thinking it's a slowly dying battery, I just want to make sure that it isn't a pump issue. If I hear the intank pump turn on when I turn the key to "on," I should assume all is well, correct? I know I may have some deteriorated lines inside, but in general if you hear it, it should be working, right?
 
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