New cause of stuttering!

Hello fellow enthusiasts!

Hab letzte woche meine kupplung gewechselt und dabei unteranderem auch die Tachowelle abgetrennt! Zu meiner großen Freude war das vorher vorhandene ruckeln (zwischen 1250 und 2000 im vierten und fünften) völlig verschwunden. Daraus schloß ich dann, dass das ruckeln mit der kupplung zu tun hatte, aber weit verfehlt. Nach einigen hundert kilometern hab ich mich dann dazu überrungen meine Tachowelle, wieder einzubauen und sofort war auch wieder das ruckeln da. Then today I tried again, and got the same result!

So, the speedometer sensor must be somehow related to the jerking/stuttering issue! I just don't know how. In my opinion, the mechanical speed indicator is a completely independent measurement.

Now, my question to the community: Has anyone had similar experiences? And does anyone have any ideas regarding the connection between tachometer fluctuations and engine jerking/stuttering?

Best regards,
Wolfgang.

P.S.: I drive a Passat 1Z, which has been chipped (for the last 500 km). It has a faulty EGR valve, and the mileage is 177,000 km. There's been a rough idling issue for about 25,000 km at low RPM (1250-2000) when using little gas or driving at a constant speed of 80-100 km/h. Adjusting the idle injection volume using VAG from 2.4 mg/stroke to 4 mg/stroke didn't solve the problem!

Hello Wolfgang,

What is the model year?

Sorry, das hab ich wohl vergessen!! A 1994 [model/year].

Best regards.
wolfgang

Hi,

Dashboard wave?

My Golf had an electronic speedometer, and the jerking stopped when the speed sensor was disconnected. According to Bosch service, this indicates a faulty mass airflow sensor. If the speed signal is not present for the engine computer, the comfort functions (e.g., jerk dampening, "torque cutoff," etc.) are not active.
I now believe that the engine control unit's electronic components and the ESP system (due to wear and tear) are no longer working in harmony, and that this is causing the jerking.

Hello,

This error is often caused by a software issue. We had a similar problem here in the forum some time ago.

Hi!!

@Bertil: Ich weiß, dass die neueren Modelle einen elektronischen Tacho (el. Geber) haben. Bie mir allerdings, gibts keinen el. Geber sondern eine biegsame Welle die den Tacho direkt mit dem Differential verbindet! Daher auch meine Frage: Wenn kein el. Geber vorhanden ist, wird der Motorcomputer auch kein signal bekommen und daraus folgt, dass der Fehler nichts mit dem Motor-STG zu tun hat. The question that still remains is: Why does the shaking stop when the speedometer cable is disconnected?

Best regards,
wolfgang

Hi,
If the vehicle still has a shaft installed, then the speed signal is likely generated in the instrument cluster using a Hall sensor. Therefore, the control unit receives the necessary information.

Best regards, Andy.

Andy wrote:

... If the vehicle still has a shaft installed, then the speed signal is likely generated in the instrument cluster using a Hall sensor. Therefore, the control unit receives the information it needs. ...

Hi,

Thank you for the answer!

It is indeed the case that the hall sensor located near the instrument cluster provides the necessary signals to both the Electronic Data Controller (EDC) and the radio (GALA).

So, it's not a new cause, but rather a well-known phenomenon that we have described several times before.

Got it, same here.
Yesterday, I finally connected the speed sensor , and the jerking stopped. However, it still doesn't run any better...
I browsed through the forum a bit yesterday. But was there really no other solution besides trading?

DocSnydor wrote:

... Eine Lösung ausser Tausch gabs aber nicht, oder?

Hi,

"As far as I know, there's no other (permanent) solution available. And nothing contradictory has been reported here in the forum either."

I've been giving Michael II's statement a lot of thought.

Michael II wrote:

... This error is often caused by a software problem.

Some time ago, we had something similar here in the forum. }

Since the error is occurring frequently with the 1Z component across various applications, that's certainly a possibility.
Why doesn't the error occur in other engines as well?
For example, the AHF has a similar pump (at least the mechanics are the same).
Here's my idea about that:
As mentioned earlier, I suspect the ESP is experiencing problems due to wear and tear. Normally, the electronics should be able to compensate for these tolerances. If it's truly a software error, that suggests the software isn't capable of compensating for those tolerances. However, this raises another question: Why weren't any corrections made in the various software versions? Has this "error" been unknowingly carried over repeatedly?

@bertil

Perhaps. If I understand correctly, the error only occurs after higher mileage. Maybe the problem wasn't recognized at that point in time.
'I also experienced some slight jerking. I cleaned the LMM (mass airflow sensor), and it almost went away, but not completely. It didn't bother me too much. During my experiments with various ECUs (engine control units) regarding VAG-COM, I discovered that an ECU from 1997, intended as a Bosch replacement for the 1Z model, no longer exhibited any jerking when using the default settings. The ECU is constructed very differently from the original; it only has one circuit board and no more plugged-in/soldered EEPROMs. I think that at some point, they recognized this problem and incorporated it into newer versions without modifying the older, established versions, following the motto 'never touch a running system.''

I've been digging around in the forum a bit more. Back then, someone suggested to Bully (who had exactly the same problem) to disconnect the speedometer. However, they always warned him about 'transient jolts' from idle to load. I tried it yesterday, and I didn't experience any jerking . That's also strange... And my 10c still shows no effect. There's probably a lot more broken .

joergs wrote:

Perhaps. If I understand correctly, the error only occurs after higher mileage. Maybe the problem wasn't recognized at that point in time.

That's exactly what I meant!

Quote:

ich habe auch ein leichtes ruckeln gehabt. lmm gesäubert. fast weg. aber nur fast. hat mich nicht weiter gestört. bei meine experimenten mit diversen stg bezüglich vag-com habe ich dann festgestellt, daß ein stg aus bj.1997 für den 1z ( als boschersatzteil ) eben mit den grundeinstellungen das ruckeln nicht mehr hat. das steuergerät ist ganz anders aufgebaut als das originale. es hat nur noch eine leiterplatte und auch keine gesteckten/gelöteten eproms mehr. ich denke mal, daß man das problem irgendwann erkannt hat und in neue versionen hat einfließen lassen ohne dabei einen eingriff an den älteren gewachsenen versionen vogenommen zu haben. getreu dem motto never touch a running system.

... Hmm, that would confirm my theory.

DocSnydor wrote:

Ich hab mal noch ein bisschen im Forum gewühlt. Damals wurde Bully (der hatte haargenau das selbe Problem) geraten, den Geschwindigkeitsmesser abzustecken. Dabei hat ihr ihm immer gewarnt vor "Übergangsrucken" von Standgas auf Last. Ich habs ja gestern mal ausprobiert und bei mir war das Rucken nicht Auch komisch... Und dann zeigt ja auch mein 10c immernoch keinerlei Wirkung. Da ist wahrscheinlich noch viel mehr kaputt...

Those affected have always written the same thing. The "10ct tuning" has little to no effect on the jerky 1Z engine (I experienced this myself - only an Authal box worked!).

Those affected have always written the same thing. The '10ct tuning' has little to no effect on the jerky 1Z engine (I experienced this myself - only an Authal box worked!).


My device always worked perfectly fine, even when there was some stuttering or lag.


Hmm, that would confirm my theory.


You're absolutely right! But what does that tell us? The old devices might have a software bug. Or maybe not. However, there's definitely no point in trying to fix it because the cost and benefit of buying a newer device are completely out of proportion!

Here's a really dumb idea: What happens if you don't send the signal from the hall sensor to the control unit (ECU)? As described, wouldn't that eliminate the jerking? What would be the ultimate consequence of the missing signal?

Hello,

joergs wrote:

welche auswirkung hätte dann das ausbleibende signal in der endkonsequenz ?

I tried it out. Without the shock absorbers, riding in stop-and-go traffic feels like being on a goat, so that's not the solution.
I once considered disabling the tachometer signal from the electronic throttle control (EDC) when...
- Speed < 30 km/h
- no gear engaged.

The problem is the throttle position sensor (TPS). By adjusting the ESP slightly (see Ulf's DIY solution in the error database), I was able to eliminate the unstable idle and jerking at 1200 rpm.

Best regards, Rainer.

Besides, doesn't that mean the turbocharger will shut off? Well, considering the current fuel prices, I don't think that's very good.