Engine stalls on cold start.

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
I've been struggling with this for a few months now, and have searched these forums with no success. Maybe I'm searching for the wrong thing.

I have a '98 Jetta, AHU engine, 317,000 miles. No modifications. The problem happens when it's been sitting overnight or all day, in temperatures up to 50 F. It hasn't been warmer than that since I noticed the problem.

I start the engine and it will idle just fine. I can run through the gears without touching the throttle for a half a mile or so and the problem will not happen. I can drive away.

If I get the revs over 1500 (20F or below) or over 2500 (40 or 50F) the engine starts running really rough. If I don't let up on the throttle, it will die. Then it's hard to start. Lots of cranking with lots of nasty, fuelly fog coming out of the exhaust. It will eventually start, and run OK. Once it's been running for a few minutes, everything is fine.

Even if I'm not moving, I can produce the problem just by gently pressing the pedal. It's almost like the engine floods.

I can't see anything unusual on VAG-COM. The intake and coolant temp sensors look normal. The fuel temp comes up in a fashion that looks normal to me. I'm not sure what to look for.

Stuff I've tried:

*Replaced fuel filter and thermostatic tee
*Replaced injection pump with a rebuilt one from Boraparts
(yup, I'm an expert at timing belt changes with VAG-COM, the timing is right in the middle.)
*Replaced nozzles about 120,000 miles ago. I took them apart recently and cleaned them up, along with the injectors.
*Tested the glow plugs (even though the engine starts quick)
*Re-checked the little hose in the ECU (it had a crack in it about 200,000 miles ago)

I'm still suspicious of the injectors, but before dumping $1000 into some rebuilt ones, I'd like to be a little more sure.

I'm hoping this is such a common problem that no one even bothers to ask here.
 

Ski in NC

Top Post Dawg
Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
A diesel can't "flood", although that's what it sounds like from the description. For it to start misfiring and stall, one of two things are going on: 1) air inlet is being restricted and not enough air is present for combustion, 2) fuel is being injected way too late when problem occurs.

Thinking the late injection. For this to occur, either ecu is commanding a certain start of injection (soi) timing, and ip is failing to respond. Or ecu is getting flaky inputs from crank sensor and or #3 injector needle lift sensor, then sends an erronious soi command to ip.

Can you get your vcds laptop set up to monitor both actual and desired soi? Then run engine and force it to where it acts up. If actual and desired match fairly closely, might look into crank position sensor. Also note the duty cycle on (I think) the cold start device..(i think) that's the timing adjusting device in ip and high or low duty cycle means it's swung all the way in one direction or the other. No expert on this system, still learning, but cheap to try.
 

KarlM

Veteran Member
Joined
Jun 20, 2004
Location
Scottsdale, AZ
TDI
1997 Jetta (black) -- 102,000 miles; 2011 Jetta SportWagen (black) -- 22,000 miles
Funky MAF? Might try unplugging it before you start the car cold and see if it affects the issue.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
Thanks

I'll have a look at the injection timing stuff this weekend.

I ran a can of purge through sometime in February (forgot to mention it).

I think I might have tried the MAF sensor, but it's all a blur now. I'll have to try that again.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
Ok, I started it today, but it was almost 60 F outside. I logged requested and actual injection timing. You can see the rpms stumble a bit after about the 20 second mark. The actual timing jumps around a bit, but I'm not sure if it's out of the ordinary.

 

vanagonjon

Well-known member
Joined
Sep 22, 2007
Location
Pelham, MA
TDI
96 Passat Wagon
I have a very similar problem. The car starts hard and when I'm driving for the first few minutes the car has a tendency to run very rough with lots of smoke. It an intermittent thing though, the car putts along fine for a few seconds, then out of no where it starts chugging and poring out white smoke, only to fix itself a minute later. I'm pretty sure the problem stems from an air leak. I intend to pick up a mighty vac and figure out where those damned bubbles are coming from once and for all. I've checked all the obvious places in a previous campaign to fix the problem, I even went as far as to plug the hole in the filter and by-pass the T fitting. Also, I swapped the IP from my spare motor but it had zero effect.

My understanding is that when there is too much air in the lines the pump cant hold pressure and the timing solenoid fails to keep time. Maybe that's what your graph is telling you. Ill let you know when I figure it out
 

Danny W

Member
Joined
Aug 12, 2010
Location
Cincinnati
TDI
Jetta
1998 TDI Jetta Cold Starts and dies

1998 AHU TDI Jetta. I have the exact same problem. Below 30F. Car starts runs 2-3 secs, stalls, then cranks and cranks. Will sputter starting with the start turning the engine. Runs poorly on its' own for 2 seconds and stalls. It can take 5 or 10 minutes of cranking engine until it finally fires up and almost immediately fixes itself (with lots of temporary smoke) Engine warms up for a couple minutes and I'm off with no hesitation. I don't see any air bubbles in the line at the fuel filter. New rebuilt injection pump, injectors, timing belt, new vacuum lines and tubing, all done by a Guru. Guru went through the glow plug system ans says everything is perfect. He thinks its electronic, maybe false readings from ECU. He pin checked ECU and found no issues. I don't know what else to do? I'm going to replace the 109 relay just for kicks. I'm guessing it could be one of the sensors sending false readings, but I have no clue where to start and I don't like just hanging parts. Tomorrow morning I'm going to unplug the new MAF sensor to see if it's an air flow issue. MAF might be defective. Let me know if and how you fixed the problem please. Thanks.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
I haven't made any progress on the problem. I did check the compression with a cold engine, and they were all in the 400-450 psi range. I am going to try an intake air temperature sensor. I'm also thinking of temporarily bypassing the intercooler. I wonder if it's a little bit clogged with oil after sitting for a while, and air rushing through it loosens things up a bit. Just grasping a little bit.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
Replaced the intake air temperature sensor, and there is no change. I also bypassed the intercooler, no change there, either. Could the MAF be reading incorrectly? There is more black smoke than there should be...
 

Ski in NC

Top Post Dawg
Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
Check oil pressure with a mechanical gauge. Get a gauge capable of reading a few hundred psi. Install gauge and watch it while reving the engine cold. If oil pressure goes super high, it can cause the cam follower hydraulic lash adjusters to cock open the valves, losing compression. If one of the regulator valves in the oil system is sticky, pressure will go super high with cold oil. Normal cold oil pressure with moderate rev I think I saw quoted as 175psi, with around 115 normal. Those numbers just what I remember from another post, not really quotable.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
I checked the oil pressure, and it's 150+. Then I mostly forgot about it for the summer. Winter is coming again, so I'm re-focused on the problem. Since last post, I replaced the EGR control solenoid (N18?), and bypassed the intercooler temporarily, with no change.

Check this out.



This is while it was running rough. The requested MAF is bouncing all over the place, and the EGR is leaping around, too. Then after a couple of minutes, it all smooths out. Now all of this might be a symptom of something else. Is it possible that collapsed cam followers are not allowing valves to open when they should, causing pressure fluctuations in the intake, thus confounding the ECU? Then, after the valve(s) start working again, it all smooths out?
 

dmck95

Member
Joined
Mar 19, 2013
Location
England
TDI
VW Bora Sport 130
does your engine block make a ticking sound or rattle for a few seconds when started from cold and then the sounds slowly fade out. Also is engine hard to rev when immediately started from cold? I have similar problem but mine stalls as soon as i get round the corner and after 2 minutes of driving its fine.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
does your engine block make a ticking sound or rattle for a few seconds when started from cold and then the sounds slowly fade out. Also is engine hard to rev when immediately started from cold? I have similar problem but mine stalls as soon as i get round the corner and after 2 minutes of driving its fine.
I haven't noticed the ticking, but it is hard to rev when immediately started from cold. If I keep the revs low for a couple of minutes, everything is fine, but if I rev it too much, too soon, it stalls.

Now that I think about it, Ski in NC might be on to something, and I just kind of blipped over his idea when I looked at my oil pressure. Maybe the problem wasn't happening when I hooked up the gauge to measure oil pressure. It would explain why the problem goes away as it runs a little bit. It also explains why, when after running for a few seconds and dying, waiting for an hour or so (for the pressure in the followers to drop) I can start the engine again.
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
I bought an oil pump, couple of bolts, and an oil pan gasket from idparts, about $130. I figured with over 400,000 mi, I should replace it rather than clean it up. I installed the pump (little over an hour) and the problem is gone. Who would have thought the oil pressure was too high? Ski in NC, that's who. PM me and I'll send pizza money. This has been dogging me for four years.

This is probably what's going on with Danny W, and maybe with dmck95. Check the oil pressure. Mine was 150+, it never occurred to me that too high could be a problem, even with Ski in NC telling me exactly that.

The funky pressure readings in my graph are likely due to air blasting past partially open valves, on both up and down strokes of the pistons.
 

Ski in NC

Top Post Dawg
Joined
Jul 7, 2008
Location
Wilmington, NC USA
TDI
2001 Jetta ALH 5sp stock
Glad it worked out!! Cam followers DO pump up enough to cock valves if oil pressure goes way high. One other guy had his oil filter blow up, that's sort of a hint there!!
 

augie dog

Veteran Member
Joined
Apr 5, 2012
Location
Apex,NC
TDI
1996 Passat
I am going to throw this out here and you can think about it or just say HUH?? I was having the same problem similar to yours. After consulting technical gurus on here we came to a conclusion it was my oil pump causing the stalling problem and evemtually blew out the oil filter when I cold started it below 32 deg. If you look for my post from early November you will see what I was experiencing. I hope this helps!!
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
augie dog, this is exactly what was (note the past tense) wrong with my car. I replaced the oil pump, and the problem went away. I feel like I have a brand new car. Replace your oil pump if you haven't done it yet.

I had the exact same symptoms, including the fast cranking like it had no compression. This was almost certainly a result of cam followers pumped up with excessive oil pressure holding the valves open. During the time I was troubleshooting, my oil cooler gasket disintegrated, spewing oil all over the place. When the engine was first started, it would run a few seconds, then wouldn't start (the no compression thing). Let it sit for an hour, it would start again, but might die again, too, depending on how cold it was. I tried all kinds of crazy crap, and sometimes I was tricked into thinking it was fixed, only to find out it wasn't.

Ski in NC told me exactly what was wrong, but I didn't "hear" him.
 

augie dog

Veteran Member
Joined
Apr 5, 2012
Location
Apex,NC
TDI
1996 Passat
I posted my situation simply as an alternative problem to consider. I agree with you jeffmon!! I am going to change out oil pump over Christmas break. In the mean time I changed oil and installed new filter and she is running good until the temp drops. I do have another vehicle to drive in the mean time.The temps here got up to 75 deg. today so Sweetpea is running GREAT!! ;);)
 

ghitaboamba

Active member
Joined
Dec 13, 2013
Location
Canada
TDI
2003 mk4 golf
I have a 2003 mk 4 with 115000 km on board with the same problem in the mornings. Could it be because of the cold starting mechanism?
Those who delt with this. What symptoms does the car show when this mechanism goes bad?
 

jeffmon

Active member
Joined
Mar 14, 2010
Location
Missouri
TDI
98 Jetta
Symptoms of high oil pressure

I have a 2003 mk 4 with 115000 km on board with the same problem in the mornings. Could it be because of the cold starting mechanism?
Those who delt with this. What symptoms does the car show when this mechanism goes bad?

I don't know about the cold start mechanism failure symptoms. Symptoms of the sticking cam follower problem caused by high oil pressure are as follows:

On a really cold morning (10F), the engine will start and run for a few (fewer than five) seconds, then die abruptly. If you try to start the engine immediately, it will turn over, but with seemingly little or no compression. It won't start. Wait an hour, it will start again, but might die again depending on how cold it is. If you decide not to wait an hour, you can crank for a long time, wear down your battery and your patience and ruin your starter motor, and it may sputter to life as you circulate your oil and beat on the cam followers with your cams.

Once it's running, if you rev the engine too high it will die again. How high that is depends on how cold your oil is. It also might not die, it might just "miss" on one or more cylinders. Once the engine oil is warm, everything is fine.

If it's quite a bit warmer outside (even 80F), the engine will start, but it will still die or sputter if you rev the engine too high before the oil heats up.

A simple way to troubleshoot the problem is to put an oil pressure gauge on your car, even temporarily. 150 psi is too high. I don't know the acceptable upper limit, but it's probably closer to 100, perhaps lower. Maybe someone else knows.
 
Last edited:

Steve Addy

Top Post Dawg
Joined
Aug 7, 2002
Location
Iowa
TDI
97 Mk3
This is all good information. This condition should be in a sticky or somewhere in a FAQ so it doesn't get lost.

This is just another reason to have a real oil pressure gauge in the car.
 

augie dog

Veteran Member
Joined
Apr 5, 2012
Location
Apex,NC
TDI
1996 Passat
jeffmon I ordered my new pump last Friday and it arrived on Monday from Bora parts. Portland,Or to Apex,Nc in three days I am impressed. Anyway we are having 60 -70 deg weather here this weekend and I will attack the oil pump. I want Sweetpea ready for a GTG in Chapin,SC at the end of January. A couple of questions for you did you use any rtv sealer along with your pan gasket and if you have torx head pan bolts what size and length of tool did you use. If you have hex head bolts then disregard my question. I have the torx head bolts. Also torque specs for pump mount bolts and pan bolts??
 

ghitaboamba

Active member
Joined
Dec 13, 2013
Location
Canada
TDI
2003 mk4 golf
My symptoms are the following ones:
we recently had -15 celsius up here in Montreal. In the morning when I try to start my 2003 ALH with 115000 km on board it takes a good 15 sec or even more of kranking before it starts. After it starts it coughs and blows white smoke for another 30 sec to 1min. Strange knocking sounds come from the engine during this time. After that it becomes nice and smooth. It starts very good after (from half a turn) even if the engine is still cold. I did not notice any loss of power.
The millage is ok, the coolant level is good, no bubles in the transparent fuel line, glow plugs are ok, fuel filter is new, air filter is new, oil filter and oil are new, batery is new, starter is newly cleaned (turning ok).
Checked the resistance of the cold start injector and is ok (15 ohms). Checked timing with vag com and it is betwin the middle and top line (a bit advanced) but in specs. Suplied 12 volts directly to glow plugs with no change.
Dont know what else to try. Please help. I am desperate.
 

ghitaboamba

Active member
Joined
Dec 13, 2013
Location
Canada
TDI
2003 mk4 golf
Forgot to mention that oil level is steady(I ve been checking for a wile).
Also cruise control is not working. Could it related to cruise control?
 
Top