ALH TDI "Cold" Start Issue

AceTdi

Well-known member
Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Researched and diagnosed relentlessly, can't figure this out.

Trouble starting from overnight sit (even in summer). Takes long cranks to start, and for first ~30sec it idles extremely rough, spewing heavy white/blue smoke. After it warms up, it purrs like a kitten. Cold starts also seem to cause massive fuel consumption (more than normal starting). Glow light plug only comes on for 1-2sec (shuts off before other dash lights when moving from key-on to start position).

Symptom seems to get worse based on how wet it is out (dew or heavy overnight or current rain). But only when cold starting (IE hot wet starting is fine). This really confuses me. I want to diagnose and fix before Canadian winter.

Diagnosis: Tested resistance in all glow plugs, all 4 are reading 0.8 to 0.9ohms. Checked glow plug harness, seems to be in good condition but unsure of proper method of testing function. There is new diesel fuel filter. Haven't gone into injector pump.

Symptoms that are NOT occurring:
-Hot starts are perfectly fine, starts on first crank when engine warm.
-Low idle when warm is excellent, purrs like a kitten.
-No smoke or power loss when engine warm.

Just cold starting issues. Please help as I am lost! PS. Model is 02 TDI Golf.
 

AceTdi

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Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Even though it runs excellent after warming up? If pump timing was out, would I not have symptoms all the time? Also, how to check timing?
 

AceTdi

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Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Excellent, there's a guy around here who has it. I'll run it over to him to check.
 

burn_your_money

Veteran Member
Joined
Oct 16, 2012
Location
Missouri
TDI
99 Beetle, 96 B4V, 05 Passat wagon
Sounds like you have air entering the fuel system somewhere allowing the fuel to drain out of the pump overnight.
 

AceTdi

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Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Burn_your_money. That was my first suspicion. Sounded like it was losing prime. I originally thought there was a fuel lifter pump so ordered a new sending unit, except I realized these cars don't have a lift pump.

Any tests I can do? Procedures to go through? This deep into diesels is above me (still learning). And I don't want to go screwing up anything on that timing belt loop.
 

burn_your_money

Veteran Member
Joined
Oct 16, 2012
Location
Missouri
TDI
99 Beetle, 96 B4V, 05 Passat wagon
Do you have a vacuum pump like a Mitivac?

Do you have clear fuel lines going to and from the pump from the filter? Even clear PVC would be fine temporarily.
 

BabyHuey

Member
Joined
May 10, 2017
Location
Wisconsin
TDI
2001 Jetta
Not looking to Hijack here, but I too have this exact problem. I do have a Mitivac and would like some info on a procedure to test the pump or lines. Thank you...
 

UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
All sorts of things enter into the picture here.

Timing
Compression
Starter
Air in fuel system

If you're not seeing any significant air bubbles in the clear fuel line going to the IP then this might not be the issue.

Cranking speed is fairly critical on a cold engine. I think that Bentley says is should be a minimum of 150 RPM: I like to see higher. If battery isn't responsible then the starter might be getting tired: many times just removing, cleaning and greasing up a bit can do wonders.

If timing is too retarded then cold starts are going to be rough.

IQ can also play a part here, though I am unsure about how much so. If IQ is high then starting tends to be a little harder.

Injectors/nozzles can also com into play, but there is lower-hanging fruit to investigate before getting to this point.
 

BabyHuey

Member
Joined
May 10, 2017
Location
Wisconsin
TDI
2001 Jetta
Thanks for the reply. No consistently noticeable bubbles in the clear fuel line, although i have seen a couple at one point.

As far as cranking. I felt it was slow, so I had the battery tested and it's good. So I pulled a used starter down and cleaned it up and installed it. Also cleaned the cables and grounds under the battery good. The cranking speed is much better and it has helped with the issue, but it still persists. Smokes like crazy and very rough for 30 secs or so. After that, it's great the rest of the day.

I bought a vcds, but am not the most computer savy guy. From what I've seen on here and the ross tech site (yes I bought the tdi club supporting member cable) my iq says it's good. It's right in the middle of the lines.

I must ad I'm fighting an intermittent limp mode condition as well, but I don't think it has anything to do with starting.
 
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UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Nobody???
I'd recommend starting your own thread in order to reduce confusion/crosstalk. This thread is pretty new and the OP hasn't had much chance to work through his problem.
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
To the OP, unless the temps in Manitoba are dipping into the mid-40sf (about 7 centigrade) or lower, glow plugs do not kick in. The light will come on for an instant at 100f (38c) but that does not mean the GPs glowed. Inside the GP relay, are two contacts, one is to send the light a signal as well as the ECU for operational purposes. The other contact sends current to the GPs. The first contact always activates when the ignition is turned ON, thus GP light for an instant on hot days or an already warmed up engine. The engine temp sensor is where the ECU gets info to activate the GP relay when temp is at or below the threshold. Do you have a DTC for the Temp Sensor (I believe the code is P0280)?

I suspect you have a timing issue as has been suggested ... the white smoke after the start-up is a pretty good indication.
 

AceTdi

Well-known member
Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Hey guys, sorry was working 14h days so didn't have a chance to look into this, back at it now. I'm going to swap out clear fuel lines to rule out fuel issue, and check timing and IQ on VCDS when I can meet with the guy around here. Also going to pull and check glow plugs.

Am I not understanding something about timing? If timing was off, would the symptoms of rough idle and white smoke not occur constantly while running? Remember they only occur for the first 15-30 sec after starting and sometimes it takes quite a few turns to pick up and run.

But after the first 30 sec running she purrs like a kitten with no smoke. Not debating, just asking. :) Sorry for going AWAL, want to figure this out before winter.

PS: No check engine lights or DTC's from my scanner.
 
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UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
Do data gathering FIRST before changing anything. Need to get VCDS hooked up.

As has been mentioned, when you first start your car/engine it is operating off of STATIC settings, hence "static timing," after which it starts running the ECU begins its magic of compensating/adjusting for all sorts of things (and does a darn fine job of it!). The issue, since things are fine when the dynamic control is operational, is STATIC. Poor timing will cause a struggle starting no matter what temps, though when warmer things should have a little bit of a leg up.

If timing is within spec (and you don't have a compression issue; and your starter is spinning the engine well) and you have hard starting after sitting for a long time then that tends to point to air incursion, fueling. I just had a slight battle with the wife's car after installing a Nicktane filter kit. It started starting like a pig (it's never been the best starter out of our lot of TDIs, but it wasn't bad). After cranking down on the filter head fittings more (and then some more) and replacing one band clamp with a screw clamp (I don't like these all that much, but I wasn't confident that the band clamp had enough "clamp" left in it) the car is starting better than ever. There's the possibility of an IP that's got sealing problems, but this is a higher-hanging fruit issue (check the easier stuff out first).
 

AceTdi

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Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Thanks for clearing that up UhOh, that makes sense between dynamic and static timing especially regarding my symptom. Don't worry I've been fixing stuff for a while, I always confirm diagnosis before R&Ring and pick low hanging fruit unless all factors confirm tougher diagnosis. No throwing parts, although I must say I'm exhausting many options. We'll get VCDS hooked up to check.

Regarding the IP "air seep" you mentioned, I've heard of this as well on other forums but it's a bit fuzzy to my brain. Is there a typical fail point on these ALH's? (IE seal in IP, etc). I should be able to confirm if this is happening with the clear hose trick as other poster mentioned, no? (IE if air seeps it should hit fuel line between pump and filter, showing bubbles?).

Side note, temps got down -1C when I tried starting a while ago, and I still noticed about a 2sec glow plug light. No CEL's and temp gauge is showing accurate on dash. Any suspicions on glow plug side? I did resistance test but kinda want to pull a couple to make sure they aren't melted off. Just got the car this spring and doubt previous owner ever replaced them during the car's 190,000km (city driven so lots of starting/short trips). From info I have, they're getting close to end of typical service life...

Complicated pest problem, thanks for helping me work through it guys!
 
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UhOh

Top Post Dawg
Joined
Dec 24, 2014
Location
PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
-1C is actually a good temp. I have found that when these cars are just at, but still above the GP threshold (41F) that they are the hardest starting (though they shouldn't be hard to start, it's just that they're not as quick to start when warmer or after the GPs have run). Anyway, a 2 sec GP light is probably about right. GP issues tend to throw CELs.

I'd leave the GPs alone for now and just concentrate on the timing and fuel issues (timing first). Again, VCDS is indispensable (this is NOT an understatement). Make sure your battery is good and that your starter is spinning some good RPMs (I like to see above 180rpm, actually 200rpm or higher, but I believe spec is said to be 150rpm): as it gets colder these things will start to get taxed.
 

AceTdi

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Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Oddly enough my battery just bit the dust while I was away, just replaced today. I suspect unrelated but will monitor. Any way to test starter rpm?

I'll ded focus on vcds. Have heard the same about its power.
 

Mantis8585

Member
Joined
Sep 28, 2017
Location
Phoenix Arizona
TDI
2000 Beetle
Once had a Cummins with similar symptoms, air seeped in somewhere and I couldnt find it. I started adding 2 stroke to my diesel and it went away. It either swelled a seal or created a vapor seal and fixed my issue. Anither bonus was cummins was quieter and smoother.
 

AceTdi

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Joined
May 9, 2017
Location
Manitoba
TDI
Golf ALH
Update of interest: As mentioned above I installed new battery. After letting car sit 8h in 4C weather the crank speed was NOTICABLY faster than ever before with old battery. So I'm starting to see what you mean UhOh. I can't speculate exact RPM, but it's fastest I've ever heard out of that car.

Interestingly enough the start was much better as well. Less rough, not as much smoke. But it was also night so tough to tell. I'm going to monitor the next few days and see. Still going to hook up VCDS too. Unfortunately the car needs to sit overnight/long period to replicate the starting symptoms so it'll take a while for me to confirm a pattern of improvement etc.

I'll update regardless. Thanks so much for your excellent insights so far guys. :)
 

Powder Hound

Top Post Dawg
Joined
Oct 25, 1999
Location
Under a Bridge, Crestview, FL, USA
TDI
'00 Golf 4dr White 5sp, '02 Jettachero 5sp, Wife's '03 NB Platinum Gray auto(!)
What does the smoke smell like? Seems to be that if it is bluish white, then it will probably smell like engine oil rather than unburned fuel. The comments about timing will be pertinent if the smoke smells like fuel. If the smell is engine oil, then you might have something more like leaky valve stem seals that allow oil to leak into the cylinder when the engine cools down. Or, it might be oil control rings that are stuck and letting too much oil by until the engine warms up just a little and expands the internal parts a bit.

My 4-dr started smoking on start up. It would smoke more the longer it sat. After replacing the valve stem seals, it quit smoking. The hardest part of this problem was figuring out whether it was rings going bad or valve stem seals. The sitting time aspect of it was what made me decide it was most likely the seals.

Back to timing: the timing adjustments the ECU can make depend on case pressure within the injection pump. That pressure is what drives the timing adjustment solenoid that is in the bottom of the pump case. If the timing is off, then it might take some time to build up enough pressure to allow the solenoid to move far enough to correct the issue. My recommendation in a case like this is first check the mechanical timing. You'd insert the cam lock and the injection pump lock pins, and see where the crank mark is. If you can't insert but one of the locks, then you need to adjust the mechanical timing and get it spot on before worrying about setting the fine adjustments electronically via VCDS.

Last, an off-the-wall possibility. I bought a used Golf that would start badly and smoke badly when the temps were in the 0-5*C range. That smoke smelled like unburned fuel. There were 2 problems, the first was the retarded timing. The second was 2 of the glow plugs were not quite seated. I theorized that those 2 cylinders ran really badly until they warmed up enough to complete the seal at the glow plugs and then the smoke cleared up. That would take 5 minutes or so. Half the threads were packed with carbon on those 2, and after replacing all 4 plugs, and fixing the retarded timing, it fired up and ran beautifully.

Good luck,

PH
 

AceTdi

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Location
Manitoba
TDI
Golf ALH
PH thanks for the incredible response. This had actually crossed my mind about oil vs fuel but I never dug in. Just did a cold start this morn (+4C), and with the new battery it turned and "caught" much faster, and ran less rough, however big plume of smoke still.

I huffed it good, it's unburned diesel for certain.

Part of the issue is fixed, now to figure the rest. I'll get these other tests going and keep y'all posted.
 

wonneber

Top Post Dawg
Joined
Oct 12, 2011
Location
Monroe, NY, USA
TDI
2014 Jetta Sportwagon,2003 Jetta 261K Sold but not forgotten
Regarding the IP "air seep" you mentioned, I've heard of this as well on other forums but it's a bit fuzzy to my brain. Is there a typical fail point on these ALH's? (IE seal in IP, etc). I should be able to confirm if this is happening with the clear hose trick as other poster mentioned, no? (IE if air seeps it should hit fuel line between pump and filter, showing bubbles?).

Side note, temps got down -1C when I tried starting a while ago, and I still noticed about a 2sec glow plug light. No CEL's and temp gauge is showing accurate on dash. Any suspicions on glow plug side? I did resistance test but kinda want to pull a couple to make sure they aren't melted off.
I found a log of air in the return line from the pump back to the filter when I had clear tubing installed to purge the pump.
I was told it could be a leaky seal in the pump itself or from the injector return hoses.
Haven't checked that so far.

I'm not a fan of resistance test for high current things like the glow plugs, starter, or such.
I do a amp test to each plug one at a time and compare the reading.
I did have a melted one in one of my Rabbit diesels.
Had the injectors cleaned & balanced before I replaced the plugs with the fast start ones they had as an upgrade.
 

KLXD

Top Post Dawg
Joined
Aug 22, 2009
Location
Lompoc, CA
TDI
'98, '2 Jettas
If you don't need the car daily you could warm it up then switch to a fuel supply suspended above the engine and run it enough to make sure all air is purged then shut it down over night and try in the morning.

With the fuel source higher than the filter air can't leak in.
 
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AceTdi

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May 9, 2017
Location
Manitoba
TDI
Golf ALH
Update: Haven't forgot about your help or suggestions. Haven't been able to connect with VCDS guy.

But we finally got a good freeze last night. Since the glow plugs activate under 7*C, a nice long glow plug heat up and the car fired right up. One would suspect the car should start worse in the cold.

Interestingly enough I also did a sub-zero start another time with a strong glow plug light, she fired right up with minimal smoke. The interesting part is I only let it run a few seconds then turned it off. Then I re-started it, no glow plug light because I suspect engine bay got above 7C from the quick idle. But sure enough, she smoked the place out and ran really rough on the second start.

I have no idea why a glow plug system would be built to not come on for a non-started car. It doesn't make sense. Diesel needs heat to combust. That either comes via synthetic heat of a glow plug, or a fully heated engine.

All diagnostics and experiments I've done point simply to a poorly designed glow plug system. Because when the chamber has heat (either via a fully heated engine, or an activated glow plug below the 7C commonly suggested threshold, she fires up very reasonably). I can't find any other explanation that this unless something else unfolds as temperatures drop.

I'm going to call this tentatively solved, but open for discussion!
 

UhOh

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Dec 24, 2014
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PNW
TDI
2000 & 2003 Golf GLS (2005 Mercedes E320 CDI)
:confused:

Really, there are PLENTY of people that do NOT have cold start issues.

Maybe your compression is bad? That would be from "defective" owners (perhaps someone in the past had a runaway or TB event and bent some rods), not a defective system.

There's a sensor that senses ambient temps. I suppose it's possible that if the engine starts for a bit that it could generate enough heat that would cause that sensor to think it's warmer out than it is, thus resulting in a no-op for the GPs, even though your engine's internals are not really quite ready to start w/o a GP cycle? There is this transition point, the cusp, where GPs aren't commanded to come on yet but ambient temps are low and the engine cold, which causes for a slightly less-smooth start. IF, as I note above, your compression is poor then this will make starting a lot harder. So... more data gathering (if you really want to get to the core of why your engine refuses to do what it should do).
 

Randomhomelesstdibeetlegu

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Joined
May 12, 2022
Location
Stinking onion land
TDI
00 ALH Tdi
N108 circuit off relay 109. Check it. I know this is ancient but for anyone else who comes across this my 109 relay wiring was and is cooked. Isolating each circuit off it with larger wiring and new inline fuses seems key. I have cold start issues on a brand new Bosch rebuilt 11mm with a lift pump. It's all electrical related.
 
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