Tuning up the Lady's Jetta, hit a snag.

Hello! It's been a while since I visited this wonderful place (according to the forum, since 11-05-08! ) Heck, that was an entire stint in the army ago. What brings me back, you ask?

Well, we have a Ford Fusion Energi lease coming up and my lovely wife asked me to find her a "cheap, fun to drive car that is reliable". So, I bought her a 2004 BEW Jetta, with a hitch! 188k on the clock. Still in remarkably good shape for the most part, very little rust.

I put a delightful carplay enabled stereo with great backup cam for her, made sure it has the heated seats, all the extras so she could feel at home...
Annnnd Taught her to drive stick so she could drive it. What a brave soul learning standard right before winter! I don't deserve her. She's actually damn good at it too, for a beginner.

I've replaced the wheel bearings, an exploded (literally) DMF with an SMF, all braking gear minus calipers, and a few other bits and bobbles. On my own, even (not bad for a moron!). She runs like a champ and actually seems to have a lot of power... although my daily driver makes north of 700lb/ft so it's hard for the butt dyno to tell, but it seems to pull well.

What's got me stuck is likely an injector issue. Before I go throwing money at it, I bought another vagcom (sold my original one years ago, oops). It'll be here soon.

What kind of issue would make the car blow a puff smoke like a 50's movie actor (but start fine) at 70F, but get out of bed like a 90 year old with rheumatism at anything below 40. We're talking 10+ second cranks here, sometimes more than once. It runs great once it's going, and restarts fine in the short term. And another oddity:

If you park it nose up it starts better and smokes less. It's a trick I used to do with a 1982 Chevy Scottsdale 6.2 diesel we had on the farm. It also doesn't seem to be running the GP any significant amount of time, even at 15F. On a whim, I pulled the temp sensor connector and no change. That said, the GP issue is likely just making the other one worse, as my original BEW had a bad relay and still started nicer with no plugs running than this one is in the cold.

So, my questions to you: What should I be looking for in VCDS to help me diagnose this issue? I'm a bit rusty on my TDI knowledge. Ideally I want to make this car so good the beautiful lady I bought it for never wants to get rid of it, so your help is appreciated, and thanks for your time!

I would start by logging blocks 1, 3, and 4, then 8 and 11, make sure to hit turbo to speed up the frame rate. We have a log viewer built into our website that you can drag/drop files onto to plot them for you. Once boost spools, which should happen by about 2200 rpm at the latest, values should be within 150mbar or so of each other, and ideally the N75 will be between 20 and 80%. Looking at 1bar stock, 1.2 or so tuned.

Is the cam original? You can also check the torsion value. There were two glow plug recalls on this car, if you don't have the newest revision, it would be wise to get them before the cold hits. Tuners can update the software, I would check with VW first to see if you quality for a free set first though.

Start with the basics:


Is the fuel filter clean? Are all vacuum lines in good condition>


1. Do a full scan for DTC's
2. Check timing

Report back.

Than you can run the logs Owain recommends.

I wish I could help. I have the ALH engine, and my wife has the BRM.

It sounds like the injectors may be either getting weak, or have a poor spray pattern. Also, could be weak glow plugs. I have replaced them in my IDI MB with the OM617.952.

Long crank times could be Cam Position Sensor. Another sensor you might want to replace is the Crank Position Sensor if you want to prevent random stalls.

Rhynri said:

What kind of issue would make the car blow a puff smoke like a 50's movie actor (but start fine) at 70F, but get out of bed like a 90 year old with rheumatism at anything below 40. We're talking 10+ second cranks here, sometimes more than once. It runs great once it's going, and restarts fine in the short term.

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What color smoke?

My '04 if left overnight will puff some white smoke when I first start it. I think white smoke is fuel. The car runs great and returns pretty decent fuel economy, so other than being annoyed I haven't really pursued it too much.

VCDS should show you what software had been installed relating to the glow plugs. I think it was MOGolf who had created a thread listing the old and new software codes.

Humbled as always by all the quick replies. You guys rock.

To answer in order:

Owain - Thanks for the helpful information. Cam is original, as far as I can tell from records. You have my gratitude especially for the recall information, as I never would have thought to look due to the age.

Aja8888 - IIRC the fuel filter was replaced by the place we bought it from, but I'll check to verify that at my next opportunity. Vacuum lines (and engine bits and bobbles in general) are actually in remarkably good condition considering the underbody engine bay panels/covers have been missing for what looks to be quite a while. Unfortunately the vagcom is taking longer than expected, ideally it was supposed to be here already. I'll update you as soon as it arrives.

RRgrassi - I actually thought it was an ALH when I picked it up, but then I saw the code in the engine compartment and remembered I'm a moron.

Ibirunner - the cranks are only long on cold starts, warm starts are basically tap the starter and go (or you know, roll start, I have a sloped driveway and may be a childish person on occasion). Is this expected with a bad Cam/Crank Position Sensor?

mjydrafter - It's certainly diesel smoke. White-blue. And it's only one puff, as in it only does it immediately upon start and it clears up the second it's idling on it's own.

JB05 - Thanks for the tip. I'll go look for it.

Thanks again, and the lady has informed me it's not "the jetta". It's "Dieter". As in Dieter Diesel. I stand corrected!

Hello again.

VCDS has arrived, and I'll be scanning things in the morning when the lady herself can drive me around and I can do this stuff. (I'm assuming you want them measured with the engine loaded, or doesn't it matter?)

I put a dog collar on the intake pipe because it was plenty loose. Driving it around tonight I noticed that it makes a cricket like sound under anything but light acceleration and pedal-lift makes the same noise after a second or so. Just another oddity, and no idea what would turn a Jetta into a 'bug'. Will update in the morning with log-viewer links after I take the measurements. I'll also take measurements of a cold and warm start... for science!

Start with a full scan (save it) and then clear: of course, let us know what codes, if any, pop up. After logging scan again.

I have an UltraGauge on all my cars (kids' cars even have them). That or a ScanGauge are invaluable in that should any CELs pop up, or codes in general, they you'll find out right away. My wife and the daughter know to notify me right away of any codes popping up: had automatic trans codes pop up on the daughter's car and I know that if the UltraGauge wasn't in the car that I wouldn't have known until I scanned the car, which is not under my local purview, so it's not often I see it).

Hello! Took the measurements. Pretty sure the Turbo setting was causing VCDS to report the wrong fields for some reason. Could be the fact the laptop I used to take the measurements was older than the car. To avoid confusing the matter, I'll only post the non-turbo sessions. Hopefully they'll be helpful.

CODES:

[01 - Engine]
16502 - Engine Coolant Temp. Sensor (G62)
P0118 - 000 - Signal too High - Intermittent

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[15 - Airbags]
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent

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[46 - Central Conv.]
01331 - Door Control Module; Driver Side (J386)
37-00 - Faulty
01332 - Door Control Module; Passenger Side (J387)
37-00 - Faulty

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And some about the radio because it's not there/aftermarket. And the log sets:

Set 1 - Warm(1,3,4)

Set 2 - Warm(8,11,13)

If you wish for me to link the turbo sets, just let me know. I'm not really sure what to read out of these, honestly.

Looking at the first set, at the end, that's idling in the garage just before the engine is shut off. Are these normal? They seem high. [note: I've no idea what a normal duration is though]:

- Injection Quantity(mg/str): 4.9
- Injection Duration(ºKW): 6.6
- Injection Start (ºBTDC): 6.8
- 903 RPM @ ~80ºC/175ºF

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Your assistance is appreciated, as always.

Might have some ground issues re the airbag stuff. Something to get around to, but not a show stopper for right now (should go through all the grounds).

The CTS can have a significant affect, this is something that is "bleeding" and should be taken care of. Look through this thread. I'd be surprised if fixing this issue didn't drastically affect the symptoms that you're having.

And that's about the limit of my comfort zone vis a vis PD engines!

UhOh said:

The CTS can have a significant affect, this is something that is "bleeding" and should be taken care of. Look through this thread.

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Thanks! The CTS is my bad. I pulled the plug a while back to see if it helped the cold starts (i.e. bad temp sensor). No dice. Then I forgot to reset stuff before driving around. So that one's actually mine. One thing I forgot to take note of in my previous post is that the offsets for idle (for injection) were quite inconsistent and pretty high.

I just ran some diesel purge through it and it sounds noticeably better while out and about, which honestly I wasn't expecting. We'll see if it helps the cold smokey starts at all. By the end of it the stuff in the jar was pretty dark.

I'm also intending to pop the lid off and inspect the cam lobes, which I have a suspicion might be a little worse for the wear. It's not exactly lumpy yet, but while running the purge through I noticed a sound that seemed a bit out of place from that general area and just want to be safe.

It's a work in progress!

Do you have any maintenance info on the timing belt?
188K miles might be close to time to change it.

wonneber said:

Do you have any maintenance info on the timing belt?
188K miles might be close to time to change it.

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The carfax isn't particularly clear about this. The people who sold it to me actually knew to check it, and said it looked to be in good shape, but we know visual inspections aren't a kosher method for checking timing belts.

It's my intent to do the timing belt/water pump changeout, but I wanted to inspect the camshaft first, so that way I can do the whole shebang at once if it needs it. Q: would an older belt be contributing to the smokey starts? (say, relaxed timing or something). I swear I've read something to that effect.

So if I understand correctly, the problem is basically that the car is hard to start when cold?

If it's not the glowplugs, then the next thing I would check is the electric fuel pump in the tank. Those commonly fail, and the car will still run, but might take a few extra seconds to start. That's what happened when mine failed.

Every time you turn the key on, that pump should run for a couple seconds. It's accessible through a hatch under the right-rear seat. It should be easy to hear it turn on, especially if you open that hatch (just three screws...easy).

Or you can disconnect the fuel line that comes out of the middle of the fuel filter and put the end in a bottle to collect the fuel. When you turn the key on (don't crank the engine) there should be a healthy stream of fuel spraying out of that line. If not, the pump is dead.

Here's a video of a guy looking at this pump: https://www.youtube.com/watch?v=7VcDiE4Mew0

Rhynri said:

The carfax isn't particularly clear about this. The people who sold it to me actually knew to check it, and said it looked to be in good shape, but we know visual inspections aren't a kosher method for checking timing belts.
It's my intent to do the timing belt/water pump changeout, but I wanted to inspect the camshaft first, so that way I can do the whole shebang at once if it needs it. Q: would an older belt be contributing to the smokey starts? (say, relaxed timing or something). I swear I've read something to that effect.

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Carfax provides a variety of info, sometimes useful, sometimes not.
The belt is not making smoke (unless it jumped time, unlikely). Are the glow plugs working?
Could be injector seals. I recommend lots of reading for the fueling system, it's different.

That seems like a good lead. I have great ears and I've never heard it run.

To clarify: Starts when it's been sitting (say, overnight) are smokey year around and right now (10.9ºF) it pretty much takes multiple 10 second cranks before it'll start and stay running, and clouds of that white-blue diesel smoke.

Basically, it starts like an old diesel tractor.

Edit: But it runs very well once it actually starts and subsequent starts, even cold, within a few hours pop right off with minor smoke. It also starts better when it's been parked with the nose elevated.

If it turns out that the electric fuel pump isn't working, make sure you check the fuse before you replace it. You might get lucky and it's just a fuse. I can't remember which one it is.

Also, replace it soon if you need to, because it's bad for the tandem pump to run in a state where it's sucking fuel. It's a positive displacement rotary vane style pump and if it's pulling through a restriction that may cause cavitation and damage the pump.

The tandem pump is located on the end of the cylinder head, on the driver's side. One part of it is a vacuum pump and the other pumps fuel. If you follow the fuel lines from your fuel filter, across the front of the engine, one of them will lead to the inlet of the tandem pump. That pump is the reason your car may still run without the electric pump (although possibly poorly).

A quick check for the in-tank pump is to pull the thermostatic T on the fuel filter and see if the filter is full or not. It should be full

Check glowplugs are they NGK?

So the BEW motor historically had reports of hard starting in the cold, and VW had a series of TSB campaigns to address customer complaints. The fixes were often at no charge to the customers, but had mixed results.

Mine was recommended for go tsb at the dealer, and was done - but incompletely.
I think it would have been in 2008.
I had hard starting in the cold for a couple of years as a Result of the TSB work, UNTIL I found this thread:

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

It is very detailed with great pictures that still come through (no photobucket problem ). You might want to run you VIN through vincoder:
https://www.vindecoderz.com/EN/Volkswagen
, or call a VW dealer to find out which if any glow plug TSB's have been performed on your car.

My car now starts in cold within .25 seconds, almost instantaneously.
(But haven't tried in the MN winters!!!)

Rhynri said:

I can do the whole shebang at once if it needs it.
Q: would an older belt be contributing to the smokey starts? (say, relaxed timing or something). I swear I've read something to that effect.

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Just wanted to make sure you were aware of the belt.

I would think the belt would have to be so loose the injection timing is retarded to cause white smoke and maybe problems starting.
Don't run the car if it's that bad.

wonneber said:

Just wanted to make sure you were aware of the belt.

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Thanks!

wonneber said:

I would think the belt would have to be so loose the injection timing is retarded to cause white smoke and maybe problems starting.
Don't run the car if it's that bad.

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Ever write something then look at it later and be like "I'm an idiot". Yeah, if it had somehow slipped it'd be really loose, and you know, that VCDS run I just did would have shown it. Derp.

Mike_04GolfTDI said:

Also, replace it soon if you need to, because it's bad for the tandem pump to run in a state where it's sucking fuel. It's a positive displacement rotary vane style pump and if it's pulling through a restriction that may cause cavitation and damage the pump.\

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So, I'm pretty sure the electric one isn't running. But I had a random question about this:

Wouldn't the tandem pump not be pulling against a restriction because of the return line loop back to the fuel filter? To me it looks like you have the loop from the tank to the filter, then that tank-side return, and the loop from the filter to the engine and a filter side return. Or am I misunderstanding this and it's actually sending all the way back to the tank from the engine?

Not doubting you, just trying to increase my understanding of how this all works!

Rhynri said:

So, I'm pretty sure the electric one isn't running. But I had a random question about this:
Wouldn't the tandem pump not be pulling against a restriction because of the return line loop back to the fuel filter? To me it looks like you have the loop from the tank to the filter, then that tank-side return, and the loop from the filter to the engine and a filter side return. Or am I misunderstanding this and it's actually sending all the way back to the tank from the engine?
Not doubting you, just trying to increase my understanding of how this all works!

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The electric pump in the tank sends fuel to the inlet connection of the fuel filter under the hood.

The connection that comes out the middle of the canister is the clean fuel that goes to the tandem pump.

The other connection that has a plastic "T" fitting is the return line. This is needed because the tandem pump pumps a larger volume of fuel than what the engine consumes. There are passages in the head that provide fuel to the injectors, and there's a mechanism to keep those passages at a certain pressure. excess fuel is returned through the return line (otherwise the pressure would just go up and up until something broke, probably the pump).

The plastic "T" fitting in the top of the fuel filter is basically a temperature controlled diverter valve. When fuel is cold, it dumps the fuel back into the filter, which is supposed to help warm it up so the fuel doesn't gel. When the fuel is warm, it just goes back to the tank.

Underneath the car there is a fuel cooler. I believe it would be on the return line. In a PD engine, the fuel can get really hot, so that fuel cooler can be used to cool it down.

If the tandem pump has to pull fuel through the filter, and the possible restriction caused by a dead electric pump, then there may be cavitation occurring at the inlet, and maybe a lack of adequate fuel supply to the injectors.

A dead electric pump in your tank could definitely cause poor starting issues such as you've experienced.

Interesting reading: https://www.michael-smith-engineers...es/NPSHR-&-it's-effect-on-Rotary-PD-Pumps.pdf

Mike_04GolfTDI said:

The electric pump in the tank sends fuel to the inlet connection of the fuel filter under the hood...

...Interesting reading: https://www.michael-smith-engineers...es/NPSHR-&-it's-effect-on-Rotary-PD-Pumps.pdf

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Fascinating! Thanks for the great explanation. This thread has been very educational.

Out of curiosity I looked up some properties of diesel fuel, and it takes 15" Hg (inches of mercury) or -7.346565 PSI to cause air that is entrained in the fuel to vaporize causing bubbles.

Could the tandem pump pull a vacuum of -7 PSI or 15"Hg when the electric pump doesn't work? I would say very likely yes. That's not much of a stretch for a positive displacement pump powered by a 1.9L turbo diesel engine, pulling fuel through a long thin hose, a dead electric pump, and a fuel filter.

So the electric pump provides just a little pressure to reduce or eliminate the possibility of air or vapor entrained in the fuel from forming bubbles.

If you go ahead and replace that electric pump, I'd be curious to hear if it solves your problem. Hopefully it does!

What does your intake manifold look like? I have an ALH and a bew, had to clean out the manifold twice with smoking as you describe..Pop the pipe and get a flashlight or take some flash pics, could be plugged.

Mike_04GolfTDI said:

Out of curiosity I looked up some properties of diesel fuel, and it takes 15" Hg (inches of mercury) or -7.346565 PSI to cause air that is entrained in the fuel to vaporize causing bubbles.

Could the tandem pump pull a vacuum of -7 PSI or 15"Hg when the electric pump doesn't work? I would say very likely yes. That's not much of a stretch for a positive displacement pump powered by a 1.9L turbo diesel engine, pulling fuel through a long thin hose, a dead electric pump, and a fuel filter.

So the electric pump provides just a little pressure to reduce or eliminate the possibility of air or vapor entrained in the fuel from forming bubbles.

If you go ahead and replace that electric pump, I'd be curious to hear if it solves your problem. Hopefully it does!

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That science is freaking fascinating! I love that stuff.

On the the latest progress report.

I replaced the electric pump, and it was most definitely dead. It didn't solve the hard starting problem, but it did improve on it in a crucial way - once it catches it runs much smoother and stays running. And either way I'm reducing the load on my tandem pump, so worth doing. I've also replaced both rear calipers because they were hanging up when you let the e-brake off, and only one was working. In addition, I did the driver side CV and bled clutch and all four corners (as you'd expect.) That's part of why it took me so long to get back to this thread, so my apologies.

indysoto said:

What does your intake manifold look like? I have an ALH and a bew, had to clean out the manifold twice with smoking as you describe..Pop the pipe and get a flashlight or take some flash pics, could be plugged.

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It might be clogged a little, but if this was influencing the starting, I'd expect it to start hard on a second start attempt. I could start it (with a hard start), back it out of the garage, shut it off. It'd start immediately as long as I tried again within a short interval (or longer if it's been running longer). So it's probably some of the heat retained in the heads easing the start. But that's just a guess. Which leads me to:

The glow plug TSB. I walked into the local VW, and they pulled the service/TSB records for me, and it hasn't had the glow plug/hard start TSB done to it. Which is good in a way, because that means it's a likely cause. The bad news is that they no longer perform this service for you free of charge.

How do I go about doing this myself? Replace plugs with the 7v NGKs, modify harness as linked above, get a tune with the GP mod applied to it? If there are more steps than that, please chime in. And could someone clarify the proper part number for those plugs? I'd hate to put the wrong thing in.

As always, thanks in advance for all the wonderful input.