Shudder on cold start

[ClausL]

Shudder on cold start .... NOT fixed yet !

Greetings Gentlemen,

I have been reading in this forum for a while and have learned there is quite a few Diesel guru's in here

This is my first post .. so please bear with me.

I have a Skoda Octavia that is equipped with a regular TDI engine (non-PD) 90Hk from 2003. (Engine code is ALH). The car has been running just a little over 61k miles without any major problems.

The last week or so I am experiencing that my engine is shuddering in the morning when it is cold. As I live in Denmark we are facing moderate low temperatures (normally down to 20 degrees F).

The car has no problems starting at all - start first time (in a sec. or two). The car is then running in idle mode just fine for 10-15 sec. or so, then a shudder (rew's. is dropping 100 Rpm or so), then the engine is running fine again for 10-15 sec. ... then a shudder.

This procedure repeats until the car been running 300 feet’s or so. No I can put the car to stop and there is no sight of shedding. The engine is still very cold.

I have tested the car with my VAG-COM ... no errors stored!
I have checked my timing, it says: "Within spec - Dead on"

What to look for

Looking forward to your input's

Brgds
/Claus

 

[jasonTDI]

Check the glow plugs and clean the harness. Could be an issue. Bad, or starting to go bad 109 relay? Have you changed the fuel filter recently?

 

[DeafBug]

Is this just starting or has it happen it the past? All cars will have their RPMs bounce with cold engine starting/running for awhile. But normally it should be the other way around, it will bounce upward like 900-1100 RPMs. (Gassers will have a lot higher RPMs like upwards to 1800RPM.) If your is bouncing downwards, is air restricted? Intake manifold clogged? Fuel filter changed? Does the engine feel like it choking for air or something. Or does it feel that is runs steadily but a tad rough until it gets warmed up in a minute or two?

 

[ClausL]

>jasonTDI< I will check the glow plugs tomorrow and will clean the harness. Starting is no problem ! .. only problems when engine is running idle on a cold morning!. Fuel filter etc. is changed approx. 600 miles ago, as the car was due for maintainance.

>DeafBug< This problem has just started ... Thursday last week or so!
I know the engine will run just a little harder during the warm-up period. As stated to >jasonTDI< the car has just been serviced 600 miles ago, so oil filter, fuel filter, air filter etc. has been re-newed. If you are looking at the engine running in idle mode on a cold morning you can see the whole engine moves when it drops in rpm. If I use the pedal to get more rev's there is absolutely nothing wrong .. nor if I just after a start put the car in gear and starts to drive. Like i said in my first posting, if i drive just 300 feets down the road and stops to check the idle mode... it runs perfectly!
I mean the car has just been started, is still cold and has just been running a few hundred feets ???

...strange !

Brgds
/Claus L

 

[jasonTDI]

They don't jump around at idle when cold. They idle slightly up though. Not for long though. The other things that will cause crappy idle is an air leak after the turbo or a failing injection pump.

 

[ClausL]

Gents,

Today I have checked the glow plugs with a multimeter - All four of them were at 0.5 Ohms. I even took the plugs out for a visual insp. and double checked to see if they actually could glow...no problems here!

Secondly I unplugged the Coolant temp sensor to have max. glow time, so that I easier could check the glow plug harness. Plenty of power through the harness. Finally I cleaned all metal on glow plugs and used an electrical cleaning spray in/ on the GP harness.

Plugged back in the coolant sensor and cleared the failure stored in the car with VAG-COM.

Not that I have any issues in getting the car started, but I decided to do a check on the injection timing. I have read on this forum you shall aim for timing at 70 when your fuels is 110 degrees C. Before I adjusted to day mine was approx. 52 which is dead on. Now I have adjusted it so the timing is in the 69-70 range.

I even replaced the black and the blue gasket in the fuel filter. I don't know what will happen if there is a small air leak in the fuel filter?... I believe it could cause the engine miss firing or should I say "coughing"

So now I will have a wait until tomorrow morning to see if there is any improvement.

>jasonTDI< The idle is not crappy, it is more like a misfire that repeat it selves every 5-10 sec. This issue is just present in the morning when the car has not moved in 8 - 10 hours or so. If I rev. the engine up there is no misfire!.

>jasonTDI< will a failing injection pump only be noticed during idle? Because the car is running perfect! And has a torque like a ferry boat

Brgds

/Claus

 

[weedeater]

What you MAY be sensing is the increase electrical load from the coolant GPs (if you have them) when it is cold. Also, when it is chilly like this, the pump is advancing the timing via a 'cold start' device.

Frankly, if you can increase the RPMs and the motor evens out, then I would not consider this a problem.

 

[dieselvet]

Could this be an injection quantity problem causing shudder? IQ should be around 3.5-4 mg/stroke at idle, I believe.

 

[jasonTDI]

The shudder only occours if you rev it and let off. I've never seen one effect the idle. Possible though. Maybe a good injection cleaning is in order too. Couldn't hurt.

The injection pump would be noisy and have a lack of power elsewhere too. Don't think that's the issue.

 

[ClausL]

Still struggles with this shudder / miss

Hi Again,

Now it is the month of May the temperatures has gone up a lot here in Denmark (10 degrees C in the morning) but I still see the same problem.....

As I earlier described I have this shudder or more like the engine is missing a few times.

- The car always start first time within a sec. or so.
- It runs for 10 -15 sec. or so no problem.
- Then it shudders/miss (chuck-a-chuck) (engine moves violently)
- Then it will dissapear while the car is standing still in idle.

If I start the car in the morning and immediately drive off, I will still be able to feel the shudder if I have to do a stop for a red light or so (in the very first minutes). (chuck-a-chuck) and then it dissapears.

- Fuel filter is brand new (incl. gaskets)
- Air filter was changed 2.000 miles ago
- Oil was changed at the same time as the Air filter
- Glow plugs is tested to be working
- Inj. timing (warm - 68-69)
- Inj. qty (warm) (4.4 - 4.6 mg/R)
- No bubbles in fuel lines
- No extensive smoke when cold / warm
- Good MPG
- No errors can be found with VAG-Com

I have tried to increase and decrease IQ to see if this changed anything.
Still the same result !!

Could it be a sensor somewhere ? or is my engine just total !¤#! ??

If I want to record a log with VAG-Com - what channels of interest to log ?

BTW. If the engine is just the slightest warm ... NO PROBLEM at all!!!


Looking forward to any inputs from you guys.

 

[ClausL]

Anyone ?

Thanks in advance
/Claus

 

[paramedick]

Claus, check the O ring on the shut off solenoid on the top of the injector pump. I just cured essentially the same problem with a new O ring AND sensor. Some folks get by just moving the O ring back up the solenoid.

I doubt the pressure relief valve is the problem. (Saw your other post)

 

[jasonTDI]

That part if you don't know is the big nut with the little wire coming out of it right behind the metal injection lines on the pump. It's in the verticle plane.

 

[ClausL]

Hey there

This makes sense !

I know the shut off solenoid this product: http://www.hovwdiaudi.dk/product/default.asp?mode=showproduct&id=102340

Do any of you guys know the VW no. for the O-ring ?

The solenoid is not expensive at all so it is worth a try

Thanks a bunch
/Claus

 

[ClausL]

Okay so I got a new shut off solenoid and a new O-ring.

I used some of the big metric tools and got the old solenoid out.
It did not look damaged nor did the old O-ring !. In with the new one and
the ready for a test. What I noticed was a new "CLICK" sound from
the new solenoid. The car started as normal - meaning instantly .

Next morning, now ready for the real test !!! - this is where I would see the chuck-a-chuck. The car started and there was no evidence of any misfirering or shudder .

So if the old solenoid was weak and not being able to pull the small piston hard enough, there would not be a free flow of diesel to be injected into the engine!!!.


I really hope the "case is solved" ... next week will show !

Thanks a lot for all the good ideas !

 

[ClausL]

DANG !!! Still having problems !!!

I am getting frustrated now

Still having problems.. and I actually think it is getting worse.

Engine misfiring below 1300 - 1500 Rpm's for the first minute or so.
Then it smoothes out and no problems ...

Could it be my injectors leaking ? Lack of Vaccum ?


I am running out of ideas

Brgds
/Claus

 

[bam_bam_dip]

vw engine? try unplugging the maf connector. If stutering stops........first try dielectric silicon grease in the connector (cage mod). If that doesnt help, then you may have a bad maf sensor. If disconnecting alleviates the stumble, but the dielectric grease does not (when connected), then my suggestion is to try a new maf.

 

[ClausL]

Hi There,

Yes it is a VW engine. (1.9 L TDI with ALH engine code)

I have tried to un-plug the MAF. That did not help! When starting the engine it still stumbles. When driving the car with the MAF unplugged there is no PoweR / torque compared with the MAF plugged in.

Contact cleaner and unplugging / plugging the MAF 10-15 times did not help.

Looking at the balance of the injectors when the engine is warm is well within spec (i believe it is +/- 2.0)
But what I am thinking is ... what if one of the injectors is leaking fuel when the engine is stopped.. ? Could this cause misfiring until the "extra" fuel is used???. As told earlier the misfiring stops if the engine runs above 1500 rpms. and after 2 - 5 mins of normal driving there is no sign of the problem.

....Strange !!

Brgds
/Claus

 

[MattRabbit]

I have the exact same problem, and have been looking all over for a solution. I'm not sure what's going on, but it sure is annoying. I've also noticed that occasionally, I'll get a bit of extra smoke with the shuddering. I'm not sure if that has anything to do with it, but I'd really like to find the problem and kill it.

 

[MattRabbit]

I was also noticing that it feels like its running on 3 cylinders when the idle is going strange. I wonder if there's some gunk built up on one of the injectors?

Does anyone else have any ideas? This has been a problem for me for about 3 months.

 

[ClausL]

Now with video !

Hi again,

2 weeks ago I shot a video of the phenomenon.

The video shows me starting the car and during the session I am unplugging the MAF sensor.

On a normal day the "coughing" is not that bad ! .. The car had not been on the road for 5 days, a lot´s of stops and starts with the engine only running in idle.

http://home21.inet.tele.dk/ludvigsen/TDI_Cough/ALH_TDI.avi

To sum it up:
- The car always start first time within a sec. or so.
- It runs for 10 -15 sec. or so no problem.
- Then it shudders/miss (chuck-a-chuck) (engine moves violently)
- Then it will dissapear while the car is standing still in idle.

If I start the car in the morning and immediately drive off, I will still be able to feel the shudder if I have to do a stop for a red light or so (in the very first minutes). (chuck-a-chuck) and then it dissapears.

- Fuel filter is brand new (incl. gaskets)
- Air filter was changed 2.000 miles ago
- Oil was changed at the same time as the Air filter
- Glow plugs is tested to be working
- Inj. timing (warm - 68-69)
- Inj. qty (warm) (4.4 - 4.6 mg/R)
- No bubbles in fuel lines
- No extensive smoke when cold / warm
- Good MPG
- No errors can be found with VAG-Com

I have tried to increase and decrease IQ to see if this changed anything.
Still the same result !!

Could it be a sensor somewhere ? or is my engine just total !¤#! ??

If I want to record a log with VAG-Com - what channels of interest to log ?

BTW. If the engine is just the slightest warm ... NO PROBLEM at all!!!

Brgds
/Claus

 

[ClausL]

anyone ?

I think i need to call the "stealer" Monday as this is getting on my nerves!.

What about the VP37 pump?. I have heard it has a cold start unit built in.
where is it located in the pump and is this possible to check it??

Brgds
/Claus

 

[eb2143]

calling all TDI pundits!

Comon gurus, help this guy! He's given us a video and more information than you could ask for.
Notice how consistent the shudder's are from each other...spaced exactly

 

[bam_bam_dip]

Comon gurus, help this guy! He's given us a video and more information than you could ask for.
Notice how consistent the shudder's are from each other...spaced exactly

Yes, help him please. He really needs a guru, not just your average joe.

 

[rdkern]

Being an average joe, and no-one else suggesting anything, I'd map the MAF requested and actuals from the get-go some morning. I'd also do the "cage mod" and hope for the best.

Air in the lines would likely give a hard start, and I can't imagine the IP doing anything this strange.

Which brings me to suspect a sensor, and which one's better to blame things on than the MAF.

 

[no-blue-screen]

I would try running a Diesel purge. May not solve the issue, but certainly wouldn't hurt.

 

[ClausL]

Hey Guys !

Thanks for all the advice it's highly appreciated !

Let's take the latest suggestions step by step.

Rdkern:
* I have no air in the lines and no hard start
* IP is std. approx 4.4 (have tried lower and higher values)
* Cage Mod - I will try to buy some dielectrical grease tomorrow and put in on the MAF connector
* MAF - is it active in idle ? ( watch the video - you barely see it but i'm unplugging the MAF connector without any change to the result !). MAF is working as there is a big difference driving with and without MAF plugged in.

no-blue-screen:
* Diesel purge is bought - just need a little time to do a "flush"

Any suggestions is most welcome !
Thanks a bunch
/Claus

 

[ClausL]

Hi Again,

Today I tried the "Cage Mod" and added dielectrical grease inside the connector to the MAF (plenty of grease!)

The car still shutters

I have now the Diesel Purge in house - and will try it out tomorrow.

I was thinking of the Vacuum Pump could cause this shutter, as the engine bay is 50% Diesel engine and 50% vacum vent's and hoses!.

I have a brake pedal that acts a little strange and so far the Master cylinder, brake booster, brakes and brake fluid has been serviced. Even the ABS bleeding has been run - just be on the safe side!.

A mechanic told me the brake-pedal-thing could be caused by a vcuum pump that is still working but not in an optimal way ????

I would be glad for any advice you can give !

Thanks a bunch
/Claus

 

[Kapuhy]

Ok, I am an average joe.
Is the effect exactly the same in winter as now in summer? Just to check if the outside temperature's got some influence or not.
You said glow plugs are fine... I have Passat 1.9 TDI and I can hear the switch "click" in the fuse box when glow plugs go off while the engine gets its first 2500 revs after the start. Can you hear that in your Skoda as well? Glow plugs won't go on if coolant is more than 9 deg. C though.

 

[TXBilll]

I'm in because my 2000 Golf does the same thing. I have been living with it for over a year now. Demontrond VW tried to fix it by adjusting the pump timing but that did not fix it. Mine's an automatic and only does this a) at idle in park, or b)when coming to a stop, the whole car stutters sometimes. It happens sometimes if i am at a dead stop with my foot on the brake in gear, but if i turn up the AC all the way the stutter/shake goes away. Oh, and mine sounds like it's running on 2 cylinders when this happens because it's really even. Also, this happens all day long, whether it's cold, hot, after a long drive or a short hop.