'04 PD sudden death after 2 blocks - Lift Pump?

This is just a quick post to see if I can get a consensus on the following symptom. My automatic 2004 automatic PD has been giving us some problems recently and my wife is now afraid to take the car out on her own.

The recurring issue is that we start the car, get about a block or two away, get to the first or second stop sign and the car dies. On restart, the engine turns over fine so the battery is fine. On both occasions that this happened, after turning the engine for a battery punishing long time, it does finally start again. Once running, I've been able to get it going again by using the tiptronic function and keeping the revs hi until it's properly warmed up. After that, it seems to run just fine. The engine does not throw a CEL so my suspicion is that it is a fuel issue. I'm going to replace the fuel filter myself today to try ruling things out one at a time, but from my initial investigation on the site - it sounds like it might be the lift pump.

So my questions for anyone who might know:

- Does it sound like I'm on the right track? - ie the lift pump?
- Is there an easy way to determine if the lift pump is shot?
- If it is the lift pump, is it something easy to replace yourself?
- If it is easy to replace yourself, where's the best place to order one, and how much would be a good price?

Thanks in advance for any input on this one.

Beacher

Sounds very much like it could be the lift pump with most likely a stopped up fuel filter. The Tandem Pump could also be clogged or giving issues.

Lift up the right back seat and lift up the split piece of carpet. You will see a cover there with 3 screws holding it down. Put your ear down near the cover and have someone just turn the ignition switch to the run position. Do not try to start it. You should hear the pump run for about 3 seconds. If it does run, then you can take the fuel line off the filter that is going to the fuel rails. Put the line into a small container and have the ignition switch cycled again. You should see a couple of ounces of fuel come out. If all that is good then your issues are most likely in the Tandem Pump area.

If it did not run, then you can check to make sure voltage is on 2 of the terminals when the switch is cycled. Should be 12 V between 2 of them and nothing between the other 2 as they are your fuel sending unit.

TW

Dead on TW,
The power is put to the outer two terminals, 1 and 4.

http://forums.tdiclub.com/showthread.php?t=225672 post #5 for how to remove and replace the pump.

Dan

Hey thanks TW and DanG - very helpful - I'm checking with a buddy today.

Update: - I replaced the fuel filter and primed it with diesel. I checked whether the lift pump at least sounds like it's working and there is a sound for a couple of seconds coming from it as you described. I made the mistake of letting the car sit for 45 mins or so before starting after the fuel filter replacement. It started but stalled after 20 seconds or so in idle. Thereafter it took a lot of cranks to get it going again, but ran fine thereafter. I got the car out and ran it up to full operating temperature, and did a couple or errands. Each time I restarted there was no issue, so I suspect that the fuel filter may have been the culprit after all.

However - If I can hear the lift pump working, should I still do the flow test to see if a couple of ounces do come out at the fuel filter?

The lift pumps often become inconsistent and erratic in their operation at the end of their lives.

They sometimes run, and sometimes do not.

I would do the flow test, since it is cheap and easy to do.

But I would also periodically check that the lift pump is running. If you catch it NOT running one time, then replace it to avoid future problems.

If it strands you, it can often be coaxed back into operation by a good thump on the bottom of the fuel tank. If the bottom of the tank is not accessible (due to say several feet of snow and ice) then remove the cover under the rear seat (keep the large phillips head screwdriver handy), and whack it on the top.

The shock may vibrate the brushes in the DC motor into making contact again for a short while. This trick will only get you to where you can replace it.

Ok DanG - I'll test it tonight or tomorrow and update later.

Thanks again for all the input - it's been very, very helpful, and saved me from a long drive to have it looked at, at least for now. So thanks!

TurbineWhine said:

If it does run, then you can take the fuel line off the filter that is going to the fuel rails. Put the line into a small container and have the ignition switch cycled again. You should see a couple of ounces of fuel come out. If all that is good then your issues are most likely in the Tandem Pump area.

TW

Click to expand...

To be specific on this - I gather the lift pump sends fuel through the fuel filter, and then from the fuel filter to the rails. I think the lines that emerge on the inboard side (close to the cabin and attached to a tee clipped in with a mickey mouse clip) are the ones that go to the rail, so do you mean to take one of the other two off? and would fuel come out of the line as well as the filter? or should I be taking both of those lines (the ones that both have their own nipple to connect to) off for this test?

Thanks

The two lines that go through the tee are return lines from the engine to the tee, the tee to the tank. When very cold, the returning fuel dumps into the filter through that tee.

The line from the center of the filter to the engine is the clean filtered fuel.

The remaining line, which goes into the edge of the filter is fuel from the tank.

So if you measure the fuel flow out of the filter you check the performance of your filter and pump combination.

If you measure the flow to the filter, you check your pump's performance.

Normally with a clean filter and ungelled fuel, they are so close in performance as to be indistiquishable.

You should get over 3 liters per minute out of your fuel pump when it is running continuously (say powered directly from a battery.)

3000lpm/60seconds/min= 50 cc/sec. So I generally tell people they should see something close to 50 cc for every key cycle.

http://forums.tdiclub.com/showpost.php?p=2362706&postcount=39 for a picture with flow arrows.

When new, blue markings on the hose denote return fuel lines, white fuel supply lines.

I just wanted to ask, so when a Lift Pump fails it is basically the electrical motor (as you said DC motor and brushes) that fail right? It the DC motor that just doesn't last?

That seems to be the most common failure.

I have seen the plastic canister that holds the fuel pump crack and break. Probably due to hitting a medium animal or some road debris impacting the bottom of the tank.

If anyone can find a source for the electric motor and pump assembly, I have a few canisters that need one.

Ok I tried testing how much fuel came out of the center port of the filter (ie - clean fuel to the engine), and I get zero flow. When we say a 'key cycle' this does not include starting the car correct?

I tried cycling the key to everything but start several times and continue to get zero flow. Despite this, on reconnecting the fuel line, it does start fine and continues to run. Am I missing something?

The PD engines have a tandem pump which creates vacuum for all the components driven by vacuum, and also sucks fuel and pushes it into the cylinder head. If there are no blockages, restrictions, or air in the lines, the tandem pump is very capable of keeping your car running without the use of the lift pump. If the car never looses its prime the tandem pump is all you'll ever need. The lift pump only cycles initially when you power on the key. Far as i know as soon as the car is running the lift pump shuts off.

You experiencing zero flow when you cycle the key is indication that your lift pump is working intermittently or has failed altogether. Now would be a good time to order one off of bleached bora. The local vendors here can get them too (precision tuning, brian harrison) but i think their prices are still higher then what aaron can get it to you for shipped.

Hope that helps!

My lift pump just went back in December and Aaron had the best pricing including shipping and customs. I paid around $300 CDN in the end.

OmegaRenegade said:

The PD engines have a tandem pump which creates vacuum for all the components driven by vacuum, and also sucks fuel and pushes it into the cylinder head. If there are no blockages, restrictions, or air in the lines, the tandem pump is very capable of keeping your car running without the use of the lift pump. If the car never looses its prime the tandem pump is all you'll ever need. The lift pump only cycles initially when you power on the key. Far as i know as soon as the car is running the lift pump shuts off.

You experiencing zero flow when you cycle the key is indication that your lift pump is working intermittently or has failed altogether. Now would be a good time to order one off of bleached bora. The local vendors here can get them too (precision tuning, brian harrison) but i think their prices are still higher then what aaron can get it to you for shipped.

Hope that helps!

Click to expand...

Actually the lift pump runs continuously once the engine starts. It cycles on for a second before starting to ensure the fuel system is pressurized. Then cycles off until the engine is running, then it comes back on.

DanG144 said:

Actually the lift pump runs continuously once the engine starts. It cycles on for a second before starting to ensure the fuel system is pressurized. Then cycles off until the engine is running, then it comes back on.

Click to expand...

i didnt think it stayed running - learn something everyday! thanks!

This is a great thread with all the right info. I've been getting nervous about the lift pump in my PD, 125k miles and it's getting noiser since about thanksgiving.

It's very audible when the key is in the on position and with the radio off you can always here it running at idle. Sometimes it seems to vary in it's amount of noise, but with some longer road trips coming up, I'm wondering if I should just bite the bullet and replace it.

Hasn't left me stranded (yet) and i'm just wondering if anyone else has experienced a pump getting noiser before it dies? Or if a clogged fuel filter would make the pump noiser for some reason?

TIA
-Jeff

the louder noise is DEFINATLEY a tell tale sign that its on its last legs. Its not a hard replacement by any means. If you know its about to go its better to be pro-active on it and get it ASAP rather then wait till it fails. The way that bastard murphey works, is it will never fail when convenient to you.

JRedig said:

This is a great thread with all the right info. I've been getting nervous about the lift pump in my PD, 125k miles and it's getting noiser since about thanksgiving.

It's very audible when the key is in the on position and with the radio off you can always here it running at idle. Sometimes it seems to vary in it's amount of noise, but with some longer road trips coming up, I'm wondering if I should just bite the bullet and replace it.

Hasn't left me stranded (yet) and i'm just wondering if anyone else has experienced a pump getting noiser before it dies? Or if a clogged fuel filter would make the pump noiser for some reason?

TIA
-Jeff

Click to expand...

This happened the morning before mine went. I have a little trouble starting it and thought it was the cold but when it turned over the pump made a different noise. I thought nothing of it and went about my day till 1:30am leaving a bar in the T.O. I went to my car to start it and drive it around a bit then pick up my friends at the door the pump quit about a block away.

I you hear a different noise coming from the pump change it, they tend to fail mo so in the winter time. Just my 2 cents.

Beacher said:

Ok I tried testing how much fuel came out of the center port of the filter (ie - clean fuel to the engine), and I get zero flow. When we say a 'key cycle' this does not include starting the car correct?

I tried cycling the key to everything but start several times and continue to get zero flow. Despite this, on reconnecting the fuel line, it does start fine and continues to run. Am I missing something?

Click to expand...

Dead in tank Lift Pump. Time to replace.

TW

Thanks for the replies guys, it keeps going, sometimes it's noisy and others it's not. I ordered a replacement to keep on the shelf, haven't had warm enough weather to want to fix it.

Cheers
Jeff

If you want to avoid the long cranking periods with a failing lift pump, the filter is usually dry after the engine dies (after the two blocks). If you are lucky you can refill the filter and it may continue to run after restart. This is in no way a good practice but you may save a starter. It still takes a good bit of starter time but nothing like having to use the starter to draw fuel all the way from the tank.

To get a failed lift pump car to the shop (some will not draw through original lift pump) use a gallon jug under the hood. Just be sure you kill the lift pump to keep it from becoming active and putting fuel everywhere.
http://forums.tdiclub.com/showthread.php?t=171541&page=2
post #19.

eddif