PD hard starting, stalled while driving

The last 10 days it has been hard to start my 04 Jetta. On most but not every morning, it took 3 15-20 second cranks to get it started even though it is kept in a garage heated to about 55F. Once it had been started once, for the rest of the day I could turn it off and leave it for hours and it would start right back up. I suspected that it was losing prime over night and checked with a hand vacuum pump when it wouldn't start, but I got bubble-free fuel in the first squeeze from the outlet of the filter and at the return line from the pump. I checked the anti shudder valve also and it's open when the no-start is happening.
Yesterday it started with just a slightly long crank, ran for a minute as I backed out of the driveway, and then stalled a few blocks later and wouldn't restart with any amount of cranking. I got out the hand vacuum, which I'd started carrying in the car just in case, and verified that there was easily pumped fuel in both the after-filter and return lines, and the anti-****ter valve was open. After doing that, which took about 10 minutes, I cranked it over for a good while, maybe 20 or 30 seconds, and it started. I drove it home and used a different car.
In all of these times there was no smoke when it finally started.
I thought maybe it might be relay 109, but the glow plug light has worked like normal when it didn't start and I have read that a bad 109 would stop that from happening. Anyone know for sure if that's a necessary condition to diagnose a bad relay 109? I would love it if it were that simple. What else should I focus on? Unfortunately I don't have VCDS anymore.
The local tdiclub-recommended shop had the car for months in the fall and had me get all the injectors rebuilt before realizing it needed a new camshaft. So I'd rather not take it to them again.
The only thing wrong with the car over the winter has been the classic persistent P0101 error, that pops up whenever it's fully up to temp and in overrun for more than a second or two.

I would verified that your lift pump in the tank and your tandem pump on your engine are working correctly
The lift pump in your tank you should hear it activate when you put the key in the on position it should run for a little bit

https://youtu.be/LhpghpQDOTU


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Engine speed sensor issue possibly.
If you have not had this done to your car you should do it whether it solves your current issue or not. It would also benefit from a software update as well.

https://forums.tdiclub.com/showthread.php?t=328868

Update: I got it started on the first try today, pulled it out of the garage and left it idle in the driveway. It stalled a few minutes later and wouldn't start again, so I've worked on it a bit this afternoon. The lift pump doesn't make a sound when the key is switched on, at least not one I can hear even with the metal cover off. I measured about a second of 12v current in the connector to the pump when I turn the key, so I know it's getting power. I don't really know how loud the pump should be, so just to be sure I checked and no fuel flows out of the lines downstream or upstream of the filter when I cycle the key. So I guess I need a new lift pump.

logos said:

Update: I got it started on the first try today, pulled it out of the garage and left it idle in the driveway. It stalled a few minutes later and wouldn't start again, so I've worked on it a bit this afternoon. The lift pump doesn't make a sound when the key is switched on, at least not one I can hear even with the metal cover off. I measured about a second of 12v current in the connector to the pump when I turn the key, so I know it's getting power. I don't really know how loud the pump should be, so just to be sure I checked and no fuel flows out of the lines downstream or upstream of the filter when I cycle the key. So I guess I need a new lift pump.

Click to expand...

I know ID parts has them in stock might take a little while to get you though not sure?
I would buy the whole unit not just a pump by itself
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Yeah, I've ordered from IDparts to Anchorage before and it does take a long time to get here unless I pay significantly more for expedited shipping. What was your reason for saying I should replace the whole unit?
I ask because I'm looking through the options now and am kind of on the fence. It seems I might lose the ability to drive without the pump working if I replace the whole unit. The one in there now is the original part, 1J0919050B (with ~270k miles!). I'm reading now that the originals have a B at the end of the part number and can allow some flow even when the pump fails. The casings on the replacement units (numbers without a B) reportedly don't allow flow from just the tandem pump suction, so I would have been stranded if I had that part when the pump motor failed.
On the other hand, all the screens in the current pump casing have a quarter million miles of muck in them, so maybe it's worth replacing the whole thing? How much extra work is it to check that the screens are clear and swap in the motor in an old housing?
Of course I just filled the tank before getting home the day before it's stalled, so I also have to figure out how the best way to get about 10 gallons of diesel out and store it if I do the swap myself. I am in a somewhat temporary living situation here, furnished rental, didn't bring all my tools to Alaska, etc.
I'm thinking of ordering the parts I want and then possibly having a mechanic with the ability to quickly deal with the fuel in the tank actually do the swap, now that I feel a tiny bit confident I understand what's wrong (famous last words...)

logos said:

Yeah, I've ordered from IDparts to Anchorage before and it does take a long time to get here unless I pay significantly more for expedited shipping. What was your reason for saying I should replace the whole unit?
I ask because I'm looking through the options now and am kind of on the fence. It seems I might lose the ability to drive without the pump working if I replace the whole unit. The one in there now is the original part, 1J0919050B (with ~270k miles!). I'm reading now that the originals have a B at the end of the part number and can allow some flow even when the pump fails. The casings on the replacement units (numbers without a B) reportedly don't allow flow from just the tandem pump suction, so I would have been stranded if I had that part when the pump motor failed.
On the other hand, all the screens in the current pump casing have a quarter million miles of muck in them, so maybe it's worth replacing the whole thing? How much extra work is it to check that the screens are clear and swap in the motor in an old housing?
Of course I just filled the tank before getting home the day before it's stalled, so I also have to figure out how the best way to get about 10 gallons of diesel out and store it if I do the swap myself. I am in a somewhat temporary living situation here, furnished rental, didn't bring all my tools to Alaska, etc.
I'm thinking of ordering the parts I want and then possibly having a mechanic with the ability to quickly deal with the fuel in the tank actually do the swap, now that I feel a tiny bit confident I understand what's wrong (famous last words...)

Click to expand...

Ok I forgot about the B suffix between the two pumps
I just thought it would be quicker and faster to change the whole unit sometimes there is Mc in the bottom of the unit but you can take that apart to clean I believe
Might be more expensive maybe faster? but any VW dealers close by that you can order the pump from?


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Not sure how do you feel about a used pump but they’re in Seattle Washington faster?


https://absolutegerman.hollandersto...pump-assembly,-diesel-(in-tank,-engine-id-bew)


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logos said:

Of course I just filled the tank before getting home the day before it's stalled, so I also have to figure out how the best way to get about 10 gallons of diesel out and store it if I do the swap myself.

Click to expand...

I know I pulled my pickup out with maybe a 1/2 tank or so.
I don't recall needing much beyond channel lock pliers, screw driver, and shop rags.
Flipped the back seat over, opened the cover and found the big nut was not really tight from the factory.

Don't know how different the BEW pump is.

Ended up not being much of a decision. The seattle place doesn't ship to Alaska, and I felt so-so about a used pump anyway. The dealer didn't have the part in stock, but they offered to order it for $500, lol. The only option that was in stock at idparts and ready to ship without extra wait time was the whole unit, so I ordered that. It sounded like getting new hoses onto the replacement motor was difficult, so probably for the best. If someone else in Anchorage reading this would like to take the original PD lift pump housing off my hands with the dead pump in it, in order to swap in the replacement motor yourself, send me a PM soon. I will hopefully have it out early next week.

Does anyone have any tips on how to get diesel out without a working lift pump or opening the tank? I know it only needs to be at about 1/2 tank, but I literally just filled up and drove maybe 3 miles before this happened, so it's completely full and I don't want to risk a fuel tsunami when I try to open the collar.

My only idea is that I might be able to siphon it out into containers from the inlet hose at the filter. If that doesn't work I guess I will have to try to get a siphon tube past the roll-over valve in the filler neck. Either way I guess I need to buy some 5 gallon containers now.

Did you try just tapping the pump with a small hammer or something to get it running so maybe you can drive it around to use some fuel ?

How about a transfer pump


https://www.buyturbopump.com/


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Update: Tapping didn't work, nor did siphoning. I used a transfer pump to take almost 10 gallons of diesel out, which made the pump replacement very neat, no spillage at all. Car is now running again (hooray). Thank you super1 for all the helpful suggestions.

But there's a new ratchet-like sound after revving it. I recorded it and posted it here
Can anyone hazard a guess what is making that sound? I'm pretty sure it didn't sound like that that before.

I still don't know what caused that sound, but it went away after a little more driving so maybe it was somehow caused by there still being air somewhere in the system. The car is running pretty smoothly and starting well now, and I can definitely hear the new pump run for a second when I turn the key. The next test will be how it does starting after sitting overnight. Maybe I should put screw-type metal hose clamps on the lines at the fuel filter - the current spring clamps seem to have lost their strength a little.

logos said:

Update: Tapping didn't work, nor did siphoning. I used a transfer pump to take almost 10 gallons of diesel out, which made the pump replacement very neat, no spillage at all. Car is now running again (hooray). Thank you super1 for all the helpful suggestions.

But there's a new ratchet-like sound after revving it. I recorded it and posted it here
Can anyone hazard a guess what is making that sound? I'm pretty sure it didn't sound like that that before.

Click to expand...

Well glad you got it running sometimes by tapping it you can get a little more life out of it but I guess yours was completely dead
I think you should be OK with it sitting for a few days but let us know how you make out anyway
You could’ve ordered those OEM fuel clamps from ID parts but too late
A lot of people like this style clamps I’m not sure if this is your size but this style

https://www.summitracing.com/parts/...5g5qAp-y8cmON-cj_gxLF_PCtgq5DFKBoC5ogQAvD_BwE

Thanks


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Yeah it's still losing prime. It sat for a day and a half and I had to turn the key 100 times to prime it again before it started. I guess I'll start with screw hose clamps at the filter and a new T fitting, and if that doesn't work suspect the tandem pump seals?

I didn't even bother with the screw hose clamps. Clamping off the return fuel line with vice grips between the tandem and the filter still results in a rough start on a couple cylinders after one night of sitting. The tandem pump is definitely leaking diesel, I think from the outer cover. I know it can also leak fuel into the crankcase oil, but I checked and the oil on the dipstick doesn't smell like diesel. As far as I can tell from carfax it's the original tandem pump. I guess I should check and see if the outer cover bolts are to spec. Anyway, it's probably time for a new tandem pump right?

Running for an extended period of time without a functional lift pump evidently causes wear and premature aging of the tandem pump, so it kinda fits.

It has a pressure gauge port for testing purposes, and there are a couple good threads here describing how to test, if you wanted to dig deeper first.

Anyone know what the torque specs are for that outer cover? All I can find are the specs for the bolts that mount the whole pump onto the block.

Vince Waldon said:

Running for an extended period of time without a functional lift pump evidently causes wear and premature aging of the tandem pump, so it kinda fits.
It has a pressure gauge port for testing purposes, and there are a couple good threads here describing how to test, if you wanted to dig deeper first.

Click to expand...

That's what I've read also, although most tandem pump replacements I've read about happened at a much lower mileage, with or without a lift pump failure. I suspect that the failure of the lift pump seals is the fault that revealed the dead lift pump. I kind of knew that there had to be at least two problems in the fuel system, since the lift pump wasn't the source of the air getting in, but I was of course hoping it would be a simpler cheaper part like the hose or the tee fitting.
As for digging deeper, I don't have a high pressure gauge to connect to the port, but I think "losing prime in 8 hours" and "fuel leak at tandem" plus "very high mileage on tandem" might be enough to justify replacing it. Would measuring the running pressure reveal a small air leak? I don't know. I also want to be using the car now that the weather is nice, so I don't have the time to wait for something like this kit to ship from Germany and then have our car be out of commission while I refurbish the pump.
I tightened most of the outer cover bolts a very tiny bit last night, but they already seemed reasonably tight and I couldn't access the lower one blocked by the coolant hose so I doubt that will help much. I poked around a bit more and I'm not sure that the outer cover is the only seal leaking. Last thing I want is to spend half a day removing and reinstalling the tandem pump to replace just the inner seal (which is the only one that idparts sells) only to have it continue leaking from the outer cover or worse the inner seals.

I replaced the tandem pump today. I am glad that I ordered the whole pump instead of just the gasket because one of the two teeth that engage the slot in the cam was missing - and it wasn't stuck in the cam, I checked very carefully while I was cleaning the old seals off the block. I'll try to embed a picture of the old pump looked like.

I had two difficulties that I had already read about in other people's posts about replacing the tandem pump, and knowing about them ahead of time helped a lot. First, the only way a tool can reach that lower smaller 5mm allen bolt is at an angle between a hard metal coolant part and some wiring. I had to buy a long ball-ended allen socket to be able to turn it, and I can imagine stripping it easily if you tried to make do without the ball end. I had ordered new bolts but I ended up reusing one of the lower allens for the lower spot because the replacement small bolts are T30 torx and there was no way a Torx tool would have worked at that angle unless you had a very flexible extension. 2nd, like others with the new lift pump, I couldn't prime by hand vacuum on the return line. It just held the vacuum and nothing flowed through. I had to prime by jumping the lift pump for a bunch of 30-second runs and then it still took a bit of cranking.

Although it might be my imagination, it does seem to drive and restart better than before. P0101 code is still there, as it has been since shortly before the camshaft needed replacing last summer.

Here's a picture of the old damaged LUK tandem pump:

It still seems to lose prime overnight. Now it has new lift pump, filter, new T fitting, new lines between filter and head, and brand new tandem pump. Runs better, still takes a minute of cranking to start first thing in the morning. I'm all out of ideas and very frustrated. I don't think I've replaced anything that wasn't about at the end of its life, except maybe the T fitting, so it hasn't been a waste. And at least it can prime itself now. But the problem remains. Help please!

Problems like this can be caused by hardened injector o rings.

Uhg! thats frustrating. I would clamp off both the supply and return hoses with some needle nose vise grips after a normal driving session. Isolate the fuel to the head and see if it still does it. If so then yeah could be injector o rings but would think you would have a massive cloud of smoke upon startup if leaking into the cylinders.

The injectors were rebuilt with new nozzles in the fall by Kerma, and I was told by the shop that installed them that every item like a seal or o-ring was replaced at that time. Still doesn't mean there isn't something leaking at the injectors. The reason I am sure it's still a prime issue is that after sitting overnight with just one needle nose vice grip clamped on the return hose between the head and the filter, it started yesterday with only a slightly rough couple of seconds. Without clamping the previous night, it failed the first 30 seconds of cranking, but with a bunch of keyturns started during the second long crank. The underneath of the tandem pump is completely dry since I replaced it. I can get another pair of vice grips and isolate the head like you suggested.

Does anyone know if the Pierburg brand tandem pump has an adjustable check valve like the Bosch?

DuraBioPwr said:

Uhg! thats frustrating. I would clamp off both the supply and return hoses with some needle nose vise grips after a normal driving session. Isolate the fuel to the head and see if it still does it. If so then yeah could be injector o rings but would think you would have a massive cloud of smoke upon startup if leaking into the cylinders.

Click to expand...

If the rubber o rings are leaking, they usually don't leak fuel into the cylinder...not unless the copper CC sealing washer is allowing that to happen. The compromised oring will pass fuel from the supply to the return fuel rail or into the crankcase.

This afternoon it started like crap even though I had a vice grip on the return line to the filter since I shut it off last night. Loud swoosh sound from the lift pump at the first key turn, long cranking, puff of smoke when it started.

With 2 vice grips on both lines at the filter isolating the tandem and head together, it started in the first few rotations after sitting for 2 1/2 days. What a roller coaster. I've had some inconsistent test results - it's confusing that the single vice grip on the return worked and then didn't work. Tonight I'm testing again whether just one vice grip on the supply hose will make it hold pressure overnight. I am having trouble understanding what possible flow path the fuel would use to get back through the filter from the supply hose, given that the supply from the tank has a check valve integrated in the lift pump that I just replaced. But this DOES suggest that the problem isn't a leaky injector or tandem pump, right? That would be nice.

2 days with just the supply clamped failed to hold prime. I can keep checking different methods of clamping to see how unreliable just the return-clamping is, and whether 2 vice grips is infallible, but it could take weeks. An oil sample dripped on a paper towel spreads out evenly, no outer ring of diesel, so I don't have reason to suspect any substantial fuel leaks into the crankcase. Am I right to assume that if the injector seals leaked between the supply and the return, that wouldn't cause loss of prime because there would be no source of air? The fuel rail in the block has communication between supply and return from the injectors anyway.

Is it worth taking the valve cover off and looking for leaking fuel when it is primed? I really don't know what to do next.

logos said:

2 days with just the supply clamped failed to hold prime. I can keep checking different methods of clamping to see how unreliable just the return-clamping is, and whether 2 vice grips is infallible, but it could take weeks. An oil sample dripped on a paper towel spreads out evenly, no outer ring of diesel, so I don't have reason to suspect any substantial fuel leaks into the crankcase. Am I right to assume that if the injector seals leaked between the supply and the return, that wouldn't cause loss of prime because there would be no source of air? The fuel rail in the block has communication between supply and return from the injectors anyway.

Is it worth taking the valve cover off and looking for leaking fuel when it is primed? I really don't know what to do next.

Click to expand...

Speculation on my part...

Leaking between supply and return can impair the tandem pump's ability to pressure the supply rail at cranking speed. That in turn can cause cavitation of the fuel to feed to the injectors.