Passat 1.9 TDI (AVF), Imbalance/Vibrations at Idle

Good evening everyone!

As announced in my first post here ( /viewtopic.php?t=29356 ), here is the "main" post:

Since I have, over the past few months – I think – probably read almost everything that has come my way regarding my problem in this and other German and English-speaking forums (e.g., also this one: /viewtopic.php?t=20003, this one: /viewtopic.php?t=8553, or this one: /viewtopic.php?t=3285), I am now quite at a loss, somewhat poorer, and the workshops I have consulted are actually still a little less knowledgeable and imaginative than I am (What doesn't appear in guided troubleshooting is simply not considered...).
Therefore, I am asking for your valued help – almost as a last resort before I set my vehicle on fire or sell it.

In October 2015, the dual-mass flywheel and clutch of my Passat were replaced due to a defective slave cylinder (see below).
After that, the car (which I inherited from my father in 2013) ran more smoothly than ever before, with less vibration and fewer difficulties shifting gears.
Approximately a year later, another improvement came from the necessary replacement of the wiring harness for the pump-nozzle injectors (PDE, see below). I was really surprised by how smoothly the engine ran afterwards.

In early December 2016, after driving approximately 4 km – and having no issues when starting the car/leaving the parking garage at home – while approaching a traffic light and coming to a stop, sudden and strong vibrations or an imbalance occurred, which were transmitted throughout the entire vehicle (steering wheel, gear stick, seat, ISOFIX adapter, pedals, bodywork, etc.). The vibrations were so intense that everything – including the forearms – visibly vibrated, which was quite alarming.

Outside the vehicle, the vibrations – sometimes even at a distance of 4 to 5 meters from the engine – are also noticeable in the ground (in parking garages, on parking lots, or even gravel surfaces), especially underneath the front bumper and next to each wheel. If this had always been the case, as workshops constantly claim, I would have noticed it before. Furthermore, the vehicle makes more of a booming noise both inside and outside than it did previously.After replacing the engine mounts (hydraulic mounts on the left and right, see below), a slight improvement has been observed.

Just so you have an idea:
The noises and vibrations in the ground feel similar to what you'd experience if a washing machine was spinning with an imbalance, or when balancing wheels but the weights are still missing.
The imbalance can also be felt in the steering wheel when the engine speed drops to idle speed during a (slow) gear change while driving.

In 2015, 2016, and 2017, the following repairs were performed on my vehicle, with all work done after December 2016 by workshops investigating the cause of the vibrations/imbalance.

21.10.2015:
Replacement of clutch and dual-mass flywheel (DMF). The clutch disc was worn due to a defect in the slave cylinder.

October 21, 2016:
Replacement wiring harness for pump-injector elements (PIE), with error codes "18074.P1666 Valve for pump/injector, cylinder 1 – N240, electrical fault in circuit" and "16685.P0301 Cylinder 1, misfire detected").

16.12.2016:
Replacement of alternator clutch, inspection of injectors (injectors for cylinders 1, 3, and 4 are okay, injector for cylinder 2 was repaired due to a significantly low idle injection volume).
(no influence on vibrations/imbalance).

December 30, 2016:
Replacement of engine-mounted hydraulic damper (left/right).
(has little influence on vibrations or imbalance; only noticeable to a lesser extent or not at all in the seat and pedals).

January 16, 2017:
Replacement rubber-to-metal transmission mount (left/right).

Air filter housing disassembled.

V-belt removed.

The motor was mounted and put into operation without using motor mounts.

Exhaust system relaxed.

Increased the idle speed from 800 to approximately 870 RPM in an attempt to mask the problem (I have since reduced it back to 819 RPM).
(except for slightly increasing the idle speed, nothing else affects the vibrations/imbalance/rattling/humming).

February 17, 2017:
Replacement of all ribbed V-belts and the tensioner (tensioner is defective).
(no influence on vibrations/imbalance/rumbling/humming).

07.04.2017:
Replacing two vacuum hoses (on the turbocharger and EGR control valve).

Replacement of the pre-injection device (PDE) in cylinder 2 (actually, according to the workshop - and despite the repair on December 16, 2017, which supposedly indicated that all PDEs were fine - it was initially the PDE in cylinder 1 that showed irregularities in idle speed regulation, but then the PDE in cylinder 2 was replaced instead).
Although the diagnostic software (BOSCH) recommended it, a compression test was not performed before replacing the glow plugs, supposedly to avoid damaging them.
Okay: The Bosch diagnostic tester has a limit of +/- 1.6 mg/stroke programmed in – until now, I was only familiar with a limit of +/- 2.8 mg/stroke... Occasionally, cylinder 1 also almost reached the Bosch limit.
(no influence on vibrations/imbalance/rumbling/humming).

April 27, 2017.
The exchange of the particulate filter element (PDE) is now also required for cylinder 1.
(no influence on vibrations/imbalance/rumbling/humming).

"Zwischenzeitlich" oder "In the meantime":

Here are a few options depending on the context:

* **Meanwhile:** (Most common and versatile)
* **In the meantime:** (Similar to "meanwhile")
* **Occasionally:** (If it means "from time to time")
* **Intermittently:** (If it means "stopping and starting again")
* **Periodically:** (If it means "at regular intervals")
* **From time to time:** (Similar to "occasionally")
* **Every now and then:** (Similar to "occasionally")
I've changed the air filter and diesel filter myself a few times in between.
(no influence on vibrations/imbalance/rumbling/humming)

Since it's been consistently warmer lately, I've noticed that the imbalance is less pronounced (e.g., in the steering wheel, but also in the road surface), and that the vibrations in the steering wheel, body, etc., decrease when the vehicle is "thoroughly warmed up" because it has been standing in the sun all day. It's better at 25°C than at 20°C, better at 20°C than at 15°C, and so on. Things are really bad below 10°C.As far as I can tell, the length of time I've been driving (i.e., engine temperature, etc.) doesn't seem to make a difference, except that the running smoothness increases slightly. The imbalance and associated vibrations remain.

Since I saw the possibility of a temperature-dependent problem (and because I've always wanted to have one ), I bought a VCDS. The AutoDia S101 that I had been using previously was also not bad, but it couldn't log data...
In my excitement about the new technology, I immediately started recording various logs (MWBs 1, 3, 10, 13, 18 and many combinations of them) - but without having read the relevant instructions here on the forum beforehand. Therefore, I won't be uploading them. Since I'm currently partially cast in plaster, I unfortunately can't create any new logs right now. If anyone would like to see them, I'd be happy to upload them later.
What other useful (or supposedly useful?) information do I have?

- Despite my clear indications that there might be an issue with the clutch or dual-mass flywheel (DMF), none of the workshops took my concerns seriously. For example, LUK describes loose or lost counterweights in its repair manual for DMFs as a cause of rumbling and vibrations. Some workshops performed the usual "function tests" (moving the vehicle while stationary, listening for rattling sounds when engaging the clutch or accelerating from low speed in a high gear), but these were unsuccessful ("It can't be that - it hasn't been long enough...").
Simply put, I have repeatedly pointed out that an imbalance in the powertrain could potentially cause the PDEs (Pressure Drop Elements) to require readjustment, especially because, according to Bosch's test results, they should actually be working correctly – although without success ("That can't be!"). I just read Mr. Kaufmann's comment in Heiner1's post a little while ago:


dieselschrauber wrote:

Hello Heiner, I suspect the unit for the fuel injection quantity deviations of the PD elements is mg/H. If all individual elements fluctuate almost between +2 and -2 mg/H, this does not indicate problems with the PD elements themselves, but rather that something may be loose in the rotating components of the engine, or that the actual fuel injection quantities are fluctuating significantly due to, for example, air (foam) in the fuel. The latter can be ruled out if the engine reaches its full power output. Too loose: Definitely check the timing belt, water pump, and all idler pulleys, as well as the ribbed belt and driven components. Don't forget to inspect the dual-mass flywheel. Best regards, Rainer



- So far, I have not been able to objectively determine any decrease in performance or changes in consumption (fuel, oil, etc.).

- It doesn't smell (other than diesel) and/or it doesn't smoke.

- Regarding the logs I created, I'll try to summarize what I think I've gathered from them:


The idle speed control system fluctuates frequently when the engine is warm, but individual values exceeding +/- 1 mg/stroke are rarely reached during idling. When the speed - whether at a standstill or while driving - is increased, it takes a few moments for the idle speed control system to stabilize again.

At first glance, the temperature sensors don't seem to be reporting any obviously nonsensical values.

The target and actual values of the exhaust gas recirculation system often do not correspond as specified by the target value (for example, at operating temperature in idle speed (819 rpm), the target value is typically 260-270, while the actual value is around 400).

While idling and at operating temperature, the EGR rate is constantly at 4.8% (I don't know the target value offhand right now).


- Trotz neuer Lager bewegt sich der Motor im Leerlauf manchmal (nicht immer!) ziemlich hin und her, mehr, als es mir vorher jemals aufgefallen ist. Ich hab versucht, die Bewegung des VW-Emblems auf der Motorabdeckung zu filmen - die Verschlusszeiten meiner Kameras bekommen das aber nicht hin. Jedenfalls ist es schwierig, die Bewegung durch Auflegen der Hände auf die Haube zu beruhigen - das ging früher. AEverything that's attached to or near the engine block is shaking violently – but not always; sometimes it doesn't shake at all.

- Direkt nach dem ersten Anlassen am Tag kann man im Innenraum für ein paar Augenblicke (mal mehr, mal weniger lang) ein Geräusch hören, dass sich in etwa anhört wie "brt-brt-brrrrt-brt-brrt". Drehzahlschwankungen sind damit keine verbunden, wohl aber ein leichtes Rucken, dass durch das Fahrzeug geht. Normalerweise verschwinden Rucken und Geräusch, sobald ich die Drehzahl kurz etwas erhöht habe. Bis zum Wiederauftreten dauert es dann eine Zeit. DThe car needs to sit for a while (and cool down?) before it can be "provoked" again.
Yesterday, right at the yard of a helpful friend – after a very quick highway drive – it was very clearly audible shortly after starting the engine to leave, and it hasn't disappeared since. The service master I quickly called over could hear it too (you can hear it well from outside the vehicle, especially near the wheel wells, with the left side being better, or between the rear of the engine block and the firewall), but he wasn't able to identify or locate the source of the noise.Set, engaged, released – gone!

- I can't detect any problems with the clutch or gear shifting.

- Imbalance/vibrations are (curiously) only really noticeable at idle speed, and do not increase when the engine is revved up. (However, it could also just be due to the frequency...)

- Depressing the clutch pedal makes no difference

.

I would really appreciate any suggestions or insights you might have, as I'm starting to run out of ideas about what could be causing this.
In a post on another forum, it turned out that the clutch was defective (springs were broken) at the end, and with similar symptoms. Unfortunately, I can't find that discussion again...

Best regards and thank you in advance.

Marc.

As you describe it (also in the thread with the part numbers for the PD elements), the engine has been completely messed up. I'm sorry, but I have to say it bluntly. I can't distinguish what of this is due to your order placement and what is related to the ability of the workshop you hired (which is not a VW dealership).
It's best to completely replace all the glow plugs with a set specifically designed for the engine, and it's also important to measure the compression. This process might reveal problems with the camshafts or the fuel system as well.
Only then can you see further. In other words, this also means that you bear the risk associated with the PD exchange.
With the results from a (possibly) unqualified workshop, you are technically correct about any errors found (though not yet in court), but you won't have a repaired car.
How are you feeling now that you've recovered? What are your own capabilities like now?
hg
Herbert.

Hello, Herbert,

Well, I wouldn't quite call it a "botched job" yet, even though it has the wrong PDE installed.

Regarding the awarding of contracts, whether it was with VAG or an independent workshop, the process followed this pattern:

Ich habe (auch schriftlich) eine Beschreibung dessen abgeliefert, was mir als "neu" an meinem Fahrzeug aufgefallen ist. Das mache ich immer so, weil ich 1. ein Laie bin (und mehr als etwas beschreiben eigentlich nicht machen kann, es sei denn, ich habe mich vorher mal damit beschäftigt) und 2. die meisten Werkstätten recht empfindlich reagieren, wenn der Kunde schon mit einer Idee angelaufen kommt, andererseits mit "Geräusche aus dem Motorraum" in der Regel noch weniger anfangen können). EActually, when I go to a workshop, I do so with the assumption that the staff there encounter such or similar problems more often than I do.
In my initial post, the information I provided, up to and including the previous repairs, is essentially what I wrote before (and which I also took from the "error descriptions").

Die Werkstätten haben sich anhand der Fehlerbeschreibung/der Beschreibung des von mir beanstandeten Verhaltens die Sache mal angeguckt, eine Fehleranalyse durchgeführt etc. und mir am Ende die identifizierte Fehlerursache benannt und mir einen Vorschlag zur Behebung gemacht (bspw. "Ihre Motorlager laufen aus. Die müssen neu"). Das habe ich z. T. mir selber noch mal zeigen lassen, dann beauftragt und bezahlt. Allerdings hat nichts davon - auch wenn es augenscheinlich trotzdem notwendig war - beim eigentlichen Problem weiter geholfen. Since several things could potentially be related to this issue, I can at least rule them out as the cause now (for example, the engine mounts, unless they were installed under tension).

Since I'm – as I said – slowly running out of ideas, I turned to this forum hoping that someone here might have a solution to my "problem."

Regarding the PDEs (Product Data Elements), I hope that at least four of them (two old ones, two new ones) will be technically compatible. Honestly, I don't really suspect they won't work, because nothing has actually changed, no matter where each one is used. Not even if the wrong one is used.
And based on everything I've read so far, the idle speed regulation seems to be...
It doesn't actually look that bad.
Plausibel erschiene mir noch Kupplung/ZMS, also eher ein mechanische Problem, besonders, weil es ja völlig spontan und ohne irgendeine Art von Vorankündigung aufgetreten ist. Ich bin mir auch nicht sicher, ob außer durch eine größere (Dreh-)Masse Schläge im Untergrund erzeugt werden können, die in ein paar Metern Entfernung noch spürbar sind. "Unsaubere Verbrennung" klingt irgendwie nicht logisch - wäre aber schon Interpretation meinerseits. Dummerweise hab ich halt keinerlei Vergleich (außer mein eigener Passat vorher und jetzt). ZMA sequential/close-ratio gearbox would definitely be a money pit.

I completely agree about the compression measurement. I was very surprised that they submerged the first PDE without having done the necessary preparations beforehand. The technician didn't understand at all why I was speechless.

Going to court would be an absolute last resort. Unfortunately, there's no gentler option beforehand – other than switching workshops and paying for it yourself.

As far as my own capabilities are concerned, they are limited, especially considering the experience I have, and even more so when it comes to the available tools. Currently, with newborn twins, I actually don't really have much time...

Why did you ask?

Regards,

Marc.

Hi Marc,


Is there any news about your tractor?

After reading that, I also immediately thought of a spontaneously failing dual-mass flywheel (DMF). Even a new one can break.

My car, with its 131 horsepower, 6-speed transmission, and all-wheel drive, also rattles. It drives wonderfully, but the rumbling is annoying. The clutch/dual mass flywheel would be a possible solution, as would the injectors and engine mounts, but the car is actually too old for all of that.

Best regards,
Mark.

Hello, Mark!

First of all, I'm sorry for the delay – the notification email ended up in my spam folder...

Actually, there's not much new to report.

Legal proceedings are underway against the workshops that cost me nearly 6,000 euros last year for services that were pointless and useless.

Last week, the car was at another workshop that I had been recommended as "good and reliable." They agreed to finally take a look at the dual-mass flywheel (DMF) and clutch for just under €200.

Unfortunately, the mechanic then – for reasons he didn't tell me and which I don't need to understand – decided to perform a guided troubleshooting process in three days without my prior consent or request. As a result of this, he replaced the mass airflow sensor (MAF) and cleaned the EGR valve – even though, due to my frequent short trips, the EGR valve is always verschandeln and I regularly replace and verschandeln it myself. If he had asked me, I could have told him.Well, I'm slowly running out of workshops in Bonn. But I'm sticking with my diagnosis.

I'm sorry that I can't help you further at the moment.

Regards,

Marc.

Hello.
I'm experiencing the exact same problem. It's a VW Passat 4motion, engine code 1.9 AVF, manufactured in 2002, with 173,000 km on the odometer.
Everything else on my car is old, except the clutch, which the previous owner supposedly replaced, but I doubt it.

I wanted to check the engine mounts because they might be the cheapest possible cause.
The problem only occurs at idle speed, around 800 RPM.
The clutch and dual-mass flywheel seem too complicated and expensive for me right now, especially since there are no issues with the driving experience.

Did the language model produce any useful results?
I'm grateful for any help. Best regards, Alex.
Run-stopping mechanism values absolute IO
Whoever finds spelling mistakes may keep them.

We place great importance on readable text here, and we have a "tool" for that purpose, called the spell checker.
hg
Herbert.

@3BGAVF:

Replacing the mass airflow sensor (MAF) with a new one did not make any difference in the measured values.

However, I wouldn't have been surprised either, because first, the deviation between the actual and target values had already caught my attention a long time ago, and second, the typical "LMM symptoms" were completely absent.

The workshop couldn't figure out where the deviation was coming from, but they left the new MAF sensor installed – and of course, also calculated its values.

Regards,

Marc.

Quote:

The workshop also couldn't figure out where the deviation was coming from, but they left the new MAF sensor installed – and of course, also calculated it...

AGR valve defective or AGR pipes blocked.

Best regards, Rainer.

Hello, Rainer,

The EGR valve itself functions correctly – I test it every time I replace it by comparing it to a freshly cleaned one using the vacuum hand pump.

What do you mean by "AGR pipes sealed"?

It is not closed down (in the sense of being permanently shut).
"Soaked"? - Perhaps...

Just to be clear: We're talking about the brass tube that runs from the exhaust manifold to the intake port, right?

I've never dared to take that part off of a car before. I had a bad experience with an A2...

Regards,

Marc.

Quote:

It is not closed down (in the sense of being decommissioned). "Soaked"? - Perhaps... For clarification: We are talking about the brass pipe that runs from the exhaust manifold to the intake port, right?

That's exactly what I mean. An air mass of 400 mg/hour at idle means "almost too much"; you would expect the engine to require 460-480 mg/hour of air.

Best regards, Rainer.

I'll connect my VCDS later and take a look. It's been quite a while since the last time I checked.

As I recall – and the workshop also confirmed – the actual value wasn't following the target value as one would expect, meaning not just at idle, but also when accelerating.

Regards,

Marc.

Here's another question about that: What would happen if the pipe were leaking?

Background: Since I've owned the car (and my father before me), there has been a kind of "whistling" sound when accelerating, as if something is leaking air. However, it's not coming from the intercooler system.

I have the impression that it was gone for at least a short time (for almost 2 kilometers), after I had kneaded the "metal mesh" that is part of the pipe (basically, a piece of flexible hose).

Regards,

Marc.

Quote:

Another question about this: What would happen if the pipe were leaking?

Nothing, because the EGR valve is located "upstream" of the pipe on that engine.

That means the exhaust pipe doesn't receive any back pressure from the exhaust manifold, right?

Regards,

Marc.

mothe071171 wrote:

Does that mean the exhaust pipe doesn't receive any back pressure from the exhaust manifold? Regards, Marc

.

But it already gets .
A hairline crack can sometimes cause a whistling sound, but it might not be particularly noticeable when comparing the expected and actual values.


What does the vacuum system look like?
If the vacuum pressure is too low, the EGR valve will not open properly either.

Check all the hoses and valves/pressure transducers throughout the entire system.
The vacuum connection fitting in the aluminum housing of the tandem pump often becomes loose -> resulting in leaks.
The rubber sleeve in the injection molding wall leading to the BKV (presumably a specific piece of equipment) is also prone to becoming porous or leaky. This is not a through-hole but rather a connector, into which connecting hoses are inserted from both sides.

Regards,
Mpire