2005 BEW PD lift pump operation and internals

[whitedog]

If you hear it, you know that the pump is getting power and that the pump is turning so you have started the troubleshooting. If it's pumping fuel to the engine, you won't know until you pull a hose off of the filter and check for fuel flow.

 

[DanG144]

If you hear it, you know that the pump is getting power and that the pump is turning so you have started the troubleshooting. If it's pumping fuel to the engine, you won't know until you pull a hose off of the filter and check for fuel flow.

whitedog (as usual is correct) and it should pump about 3 liters per minute. This is best checked by putting an extended filter outlet hose into a fuel jug. It should put out a good, hard squirt for a second or so when the key is turned on - not a dribble.

Dan

 

[whitedog]

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.

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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.

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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]

OK, so we have fuel coming out of the pump into the horizontal black line. Most of the fuel goes out the verticle black line, but some of it is routed through the eductor jet. This eductor jet provides a vacuum (Via the Vanturi Principal) that pulls fuel through the inlet check valve, keeping the pick-up/pump assembly full of new fuel. The pump only pumps the fuel that is in the assembly.

Is that correct?

 

[DanG144]

OK, so we have fuel coming out of the pump into the horizontal black line. Most of the fuel goes out the verticle black line, but some of it is routed through the eductor jet. This eductor jet provides a vacuum (Via the Vanturi Principal) that pulls fuel through the inlet check valve, keeping the pick-up/pump assembly full of new fuel. The pump only pumps the fuel that is in the assembly.

Is that correct?

Yes, you are correct, let me reword it slightly - sometimes that helps- sometimes it adds confusion. Here we go.

OK, so we have fuel coming out of the electric pump into the horizontal black line. Most of the fuel goes out the vertical black line to the fuel filter and engine, but some of it is routed through the eductor jet. This eductor jet provides a vacuum (Via the Venturi Principle) that pulls fuel through the inlet check valve, keeping the canister full of fuel fresh from the main tank body - the excess constantly overflows out the top of the canister, carrying off the warm fuel returned from the engine. The electric pump picks up fresh, cool fuel from the canister.

Dan

 

[whitedog]

the excess constantly overflows out the top of the canister, carrying off the warm fuel returned from the engine. The electric pump picks up fresh, cool fuel from the canister.

Dan

Got it.

 

[yosso]

more lift pump questions...

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?

I can hear my pump start, then stop when I turn the key. I pulled the line at the filter and no fuel flowed out of the line when the key was turned.

We were able to get fuel to flow with a mityvac. Does this sound like a dead lift pump?

2004 Jetta w/95,xxx miles.

M.

 

[DanG144]

You should get a large healthy squirt of fuel out, so something is not right. This seems to be happening more and more frequently - where people hear the pump run, but get no fuel. Yours is the 5th case reported in the last 6 weeks or so.

Was this the line to the fuel filter from the pump (not the return line with the Tee)? Or the line out of the filter to the engine?

You could have a partly to mostly clogged screen on your pump. This would let it run at reduced flow, and the eductor jet flow could be taking all of the flow produced. The pressure at the exit check valve would never get high enough to flow to the filter. But when you pulled with a mityvac it would open the check valve and pull fuel from the eductor jet.

Or your electric pump could be running at lower RPM than intended, producing low flow and low pressure.

Dan

 

[DanG144]

We are starting to get several reports of lift pumps making noise - the electric pump running - but not producing fuel at the engine compartment.

Do you think the filter screens may be clogging with gelled fuel or ice flakes? Most screens will be partially clogged already. Just due to normal junk filtered out over the years. It is the time of year to be using an anti-gel additive.

In one case on a BRM we know it was due to a bad fuel filter exit assembly - a small internal valve was broken not allowing fuel to exit to the engine.

Dan

 

[yosso]

You should get a large healthy squirt of fuel out, so something is not right. This seems to be happening more and more frequently - where people hear the pump run, but get no fuel. Yours is the 5th case reported in the last 6 weeks or so.

Was this the line to the fuel filter from the pump (not the return line with the Tee)? Or the line out of the filter to the engine?

You could have a partly to mostly clogged screen on your pump. This would let it run at reduced flow, and the eductor jet flow could be taking all of the flow produced. The pressure at the exit check valve would never get high enough to flow to the filter. But when you pulled with a mityvac it would open the check valve and pull fuel from the eductor jet.

Or your electric pump could be running at lower RPM than intended, producing low flow and low pressure.

Dan

Line #1

I've checked for codes (Scangage II) and nothing is showing...car died last week, 1/2 a tank of fuel.

 

[yosso]

We are starting to get several reports of lift pumps making noise - the electric pump running - but not producing fuel at the engine compartment.

Do you think the filter screens may be clogging with gelled fuel or ice flakes? Most screens will be partially clogged already. Just due to normal junk filtered out over the years. It is the time of year to be using an anti-gel additive.

In one case on a BRM we know it was due to a bad fuel filter exit assembly - a small internal valve was broken not allowing fuel to exit to the engine.

Dan

It has not been extremely cold yet here, at least not extended period of time.

I'm currently working one handed (broken RH wrist) so my troubleshooting has been with the assistance of others and thus limited.

Hopefully I can get some help to remove the pump tomorrow and see if cleaning the filter does anything.

Thanks again for your extremely helpful post.

M.

 

[DanG144]

I was working with another forum member this afternoon (over the phone) on cleaning his pump suction screens.

He was able to get his pump apart without removing the hoses - since he did not have replacement hoses.

He took the wires loose below the top cap.
He took the check valve off of the lower side of the top plate - the one the outlet hose hooks to.
He was then able to take the electric pump out and clean the screen.
It would have been much easier if he had had a long pick to release the clip on the lower side of the eductor housing.

The jury is still out on if it will work any better once the screens are cleaned.

Dan

 

[DanG144]

I now DO recommend the aftermarket lift pump for PDs

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 recommend it for PD's, if you do LCR's mod to it.

This pump had a shutoff head of about 13 psi, it does have an eductor built into it to provide cool fuel to the electric pump in the canister, and it has provisions which allow it to work down to low tank levels and on hills.

It flows 1 gpm, a little more than the stock lift pump.

But you will not be able to keep running your car when the electric pump quits, unless you do LCR's mod. His parts list and instructions are correct, concise, and well presented (How's that 'dog?).

Dan

 

[Left Coast Resident]

Note that you might try to use a slightly larger size piece of viton than the ~ 1/4" ID I was using to go over the 5/16" 'Tee' barbs -- there is the possibility of an eventual tear if it is not lined up to make its vertical drop DIRECTLY into the limited space where it enters the well. I haven't looked on McMaster Carr to see if they have a metric size between 1/4" and 5/16" ID, but if so, that would be a good thing. And it will have to be thin wall -- there is only a little room to drop it into the well . . .

 

[DanG144]

I have added some simple fuel system tests in Post #7.

Dan

 

[yosso]

Removing lift pump from tank...

Okay, my cast and pins have been removed, and my right hand is finally able to be utilized in fixing my 2004 Jetta...but I can't seem to get the wiring clip to release from the pump. My father removed it before, but I don't know what he did to get the clip to release.
I've attached two images of the top of the tank for visual clarification...
Thanks a bunch in advance!

 

[mctdi]

Okay, my cast and pins have been removed, and my right hand is finally able to be utilized in fixing my 2004 Jetta...but I can't seem to get the wiring clip to release from the pump. My father removed it before, but I don't know what he did to get the clip to release.
I've attached two images of the top of the tank for visual clarification...
Thanks a bunch in advance!

Here is the pump with the connector off. And the gear puller I used to turn the big plastic nut.
The nib that the connector latches on to can be seen.

I am looking for a better picture of the connector, and will post if I find one.

 

[mctdi]

Push the latch tab of the connector as arrow shows. It does not move much, and can break off.

 

[yosso]

Fuel pump float and sender.

Push the latch tab of the connector as arrow shows. It does not move much, and can break off.

Yep, and I did break it off, but I did get the connector off and the pump removed. Thanks for the assistance!
The fuel sender level broke off while I was attempting to remove the pump. I was able to retrieve the arm and float, but now I can not place the new pump down into position. I know the final orientation, but can't seem to position the float into the sump in tank correctly....anyone have any pointers?
M.

 

[mctdi]

Yep, and I did break it off, but I did get the connector off and the pump removed. Thanks for the assistance!
The fuel sender level broke off while I was attempting to remove the pump. I was able to retrieve the arm and float, but now I can not place the new pump down into position. I know the final orientation, but can't seem to position the float into the sump in tank correctly....anyone have any pointers?
M.

With the float down, you tip the whole assembly to the float side lowering the float. Float goes in to the tank first, once the float is in the tank a couple of inches, you can untip the assembly and lower the rest of the way.

 

[yosso]

With the float down, you tip the whole assembly to the float side lowering the float. Float goes in to the tank first, once the float is in the tank a couple of inches, you can untip the assembly and lower the rest of the way.

Thanks, I was finally able to conquer the install of the new lift pump. I ended up siphoning more fuel out with the car jacked up on the passenger side, that way I could see what was going on down in the tank. It also helped to install the gasket first and then push the pump into place while reinstalling the locking ring.

My battery was a bit low (been sitting since the first of November) but after a quick charge, and a bit of cranking the car started! I guess that's another 2004 Jetta with a failed lift pump (95,510 miles).

Now it's time to take the car in for it's timing belt swap. (Frank06).

Thanks you again for the assistance.

Does anyone want the failed pump for analysis?

M.

 

[DanG144]

I will pay the shipping for it. Look for a PM.

Dan

 

[aespTDI]

Okay so I finally got the LP replaced. I did have a question. While trying to place the new one in, it didn't seem to want to go in all the way. I looked at the OEM for and noticed that it compresses riding up and down on the rods.

Once the new one is in, does it need to be pressed in place allowing it to compress to fit in? Make sense??

 

[DanG144]

That is correct. The springs ensure that the suction is pressing on the bottom of the tank.

Dan

 

[aespTDI]

That's weird, the fact that I have read through many posts here on the subject and never came across that info. I was struggling to get it to fit in. I didn't want to pull it out again for fear of dripping fuel everywhere. I thought that maybe it shouldn't rest up against the bottom because that is where suction is taking place and figured it would interfere in that operation.

Am I just being picky or is this worth pointing out to those doing it for the first time?

 

[yosso]

That's weird, the fact that I have read through many posts here on the subject and never came across that info. I was struggling to get it to fit in. I didn't want to pull it out again for fear of dripping fuel everywhere. I thought that maybe it shouldn't rest up against the bottom because that is where suction is taking place and figured it would interfere in that operation.
Am I just being picky or is this worth pointing out to those doing it for the first time?

I also ran into the compression issue, it was easier to place the pump if you inserted the gasket first and the pushed the pump down. Also, it seemed to me that the new pump had stiffer springs than the old.
My tank was less than half full, more like a quarter and I ended up draining out almost five (5) gallons of fuel and also jacked up that side of the car so I could see the bottom of the tank.
Just a few more points of interest from a first timer.

 

[DanG144]

I added some notes on the spring loaded feature in post #5. Thanks for the feedback.

 

[DanG144]

how to tell a 'no suffix' pump from the 'B' variant pump.

The grey top and white bottom typically indicates the only pump now available (from vendors or dealers), with no suffix, and that will have no chance to supply fuel when it dies. This is what is typically carried by aftermarket vendors, and it sells for about $230. Note the external hose down to the eductor jet. The eductor jet can be seen from the bottom. We pulled 25" of vacuum on the fuel line from this style pump and got no fuel. The bright green high temperature viton lines are installed with Left Coast Resident's mod, the translucent white lines are stock.

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For the tan colored OEM 'B' suffix pump, with all fuel lines internal, we were able to pull adequate fuel to run the car with only 4" hg vacuum - similar to an ALH.
Note the bottom rough filter screen that covers the intake.
This pump is no longer available from dealers or vendors.

[/IMG]

If a car has no air leakage into its fuel lines, and there is nothing blocking the eductor jet then the 'B' variant pump will allow it to run after the electric pump fails. If you have an air leak or blocked eductor jet, then it will die.

 

[DanG144]

I have learned that the 'B' variant pump is no longer available from the dealer or the vendors. The only choice is the 'no-suffix' pump, and it is typically much cheaper from the vendors than from the dealers.

 

[squeegee_boy]

I replaced my original lift pump a little more than a month ago. The new pump worked great for a while (40 days), but now it is making a gurgling sound when I turn the key on. It only happens when the tank is low.
I ran the thing in a bucket and found that the pump inlet loses its prime. I see the hose that runs from the eductor to the inlet of the pump on the new style pump. When I start the pump, I get the characteristic gurgling until the line fills with fuel and purges the air bubbles. The discharge line on the pump never loses its prime. Is there a check valve on the inlet of the new style lift pumps? Is it internal to the pump?

 

[DanG144]

Both of the hoses you see are on the outlet of the pump. The small hose provides flow to the eductor jet, not from the eductor.

For the new style pump, there is a check valve on the discharge of the eductor that keeps the canister full. Since the pump sits in the canister it should never lose suction. Could you tell if your canister was staying full after the pump was shut off?

How low does your fuel level have to be before you can hear it gurgle? I would expect that it would not gurgle if you had more than about 1.5" of fuel in the tank - unless the canister was not staying full after shutdown.