Vibration localized to 1Z. What next?

Hello!

I wrote a post a while ago about the jerking issue with the 1Z engine. This was followed by several other posts that described the exact same problem. I followed all the instructions, including disconnecting the throttle position sensor, which finally did work. I was told that a faulty fuel injection pump could be tested (according to Bosch). So I disconnected the throttle position sensor, and lo and behold, the jerking was gone (the speedometer and odometer, of course, were dead). My questions now are: exactly what is wrong with the pump? Do I absolutely need a new pump, or can the damage be fixed with less financial resources? And what happens if I continue driving without the speed sensor (besides the speedometer and odometer failure)? Can it damage the engine?

I would be very grateful for your help.

Tom

Hi

If the pump were seriously broken, it probably couldn't be "repaired" by simply unplugging the (!!) speed sensor connector.

In my case, the pump is definitely started at a reduced idle speed during the initial run-in phase, meaning the engine computer responds to the speed signal.
I suspect there might be some minor issues with the interaction between the engine computer and the fuel pump, so I'd like to try the DIY fuel delivery adjustment.

/viewtopic.php?t=658

Hello,

The problem with the malfunctioning speed sensor is that your comfort functions (e.g., throttle interruption, torque limitation during acceleration...) will no longer function. However, since this also involves safety features, driving without a speed sensor will likely result in further damage later on (e.g., gearbox or crankshaft damage).


@Ulf
The pump then has a "serious" problem: The flow control valve is no longer able to follow the rapid commands from the STG because the control hysteresis is no longer functioning correctly. Subsequently, there may be over- or under-swinging in the pump's operating behavior, which then manifests as jolting.
The speed signal is required in the control unit for regulation (see above).
Nevertheless, I must agree that you should first try all other options before changing the pump!


However, I also believe that the speed sensor could be defective. A few days ago, I had a friend come to me with similar symptoms. In addition, he also had a tachometer that was vibrating (and that was while the tachometer was on!). He then replaced the sender and the shaking and tachometer jittering was gone (the lucky one!!)

Bertil wrote:

The pump then has a "serious" problem: The flow control valve is no longer able to follow the rapid commands from the STG because the control hysteresis is no longer functioning correctly. Subsequently, there may be over- or under-swinging in the pump's operating behavior, which then manifests as jolting. The speed signal is required in the control unit for regulation (see above). Nevertheless, I must agree that you should first try all other options before changing the pump! However, I also believe that the speed sensor could be defective. A few days ago, I had a friend come to me with similar symptoms. In addition, he also had a tachometer that was vibrating (and that was while the tachometer was on!). He then replaced the sender, and the shaking and tachometer jitters were gone (the lucky one!!)

Hi Bertil

only for concept comparison: Hysteresis means to me a somewhat "sluggish" response of the moving system to incoming commands.
Or even a kind of stabilizing Kipp effect, whereby a system from the middle position automatically pulls itself towards the end positions, and which, in order to change state, must first be overcome by an external influence.
(I hope my "free" definition isn't completely wrong or incomprehensible.)

Regarding the adjustment of the pump control, I can say from my experience that the tendency for jerky operation can be clearly influenced by simply adjusting the control.
Reducing the number of elements reduces or eliminates the stuttering, and vice versa.

That the (mechanical) hysteresis of the pump should be changed by simply moving the metering valve on the distributor piston is something I find difficult to imagine.
More likely, I am assuming that there is a miscalibration of the individual control behavior of the electronics and the pump, which, in total, causes the jerking motion due to "incorrect" control adjustment.

If you mean the overall behavior of the system (= electronic AND mechanical) due to incorrect hysteresis, then I agree with you.

A shaky electronic tachometer with a stepper motor clearly indicates problems with the speed measurement (or signal processing), which can certainly also lead to jerky operation through the motor computer. This is definitely not caused by the pump.

Hi Ulf,

... Hysteresis in an Inductive System...
Ola, it's been a long time... now I should probably take a look...

Okay, so: "Also, Hysterese refers to the process of charging an inductor compared to the discharge of the same." This results in a double S-shaped curve that has the same origin and the same endpoint.

In our case, this refers to the upward control mechanism using a magnet and the downward control mechanism using a spring in the signaling system. I mean the hysteresis of the entire system.
By simply moving the quantity setting device, you cannot influence the hysteresis.
However, if the engine is "over-oiled," then shifting is the correct solution.
If the shaking disappears after detaching the speedometer, it is unlikely that there is a problem with "over-oiling."


Ugh, that was a tough delivery. Hopefully, we haven't given poor TOM too much of a headache.

Bertil wrote:

However, if the engine is "over-oiled" and is shaking, then moving the oil is the correct solution. If the shaking disappears when the speedometer is disconnected, it is unlikely that there is a "over-fattening" issue.

Hi Bertil

"These, apparently, seem to be the symptoms."
How else can I explain this (using the hysteresis)?

Hi Ulf,

If the hysteresis doesn't work correctly, you'll get a pulsating oscillation in your pump control, and it will jerk!!
This means the pump regulates, and the control unit notices "too much (or too little)", and this process eventually leads to shaking. The inertia of the quantity control system does not correspond to the target value in the STG, which causes the STG to overshoot the target value during the control process, and then immediately correct itself.

However, such a process could be monitored by software , but this is not provided for in the VAG STG . It would then be possible to log this error via an error code in the STG.

I believe that both of these processes (overweight and false hysterolysis) could be causes of the jerky movement.

However, obesity should be measured using VAG COM (VAG 155*). As far as I remember from the 1Z repair manual, there is a section that specifies the target amount and the actual amount for certain loading operations.

Bertil wrote:

However, obesity should be measured using VAG COM (VAG 155*). As far as I remember from the 1Z repair manual, there is a section that specifies the target amount and the actual amount for certain loading operations.

Hi Bertil,

That may indeed be the case.

However, a too high position setting cannot be determined by 1551 . . . because the electronics do not receive a message about the actual throughput volume. The RWG feedback only includes the displacement of the signaling system.

Now, if the entire signaling system, including The RWG is still reporting, for example, "10 mg" instead of the actual amount of 15 mg, after having shifted the dosing piston so that 5 mg/KH more than intended are always dispensed.
And the 1551... can only output something based on the motor computer "sensing" the RWG signal. Therefore, obesity determined by position in a control room cannot generally be measured by diagnosis.

However, the critical situation arises in the idling range, where the engine computer is programmed with quantities of around 5 mg (?), and then "wonder" why the engine maintains idling speed despite apparently having 0 mg.
The jerky behavior may be due to certain inappropriate control strategies that the engine control unit is implementing in response to such inconsistencies

ulf wrote:

Hi Bertil, That may indeed be the case. However, a too high position setting cannot be determined by 1551 . . . because the electronics do not receive a message about the actual throughput volume. The RWG feedback only includes the displacement of the signaling system. Now, if the entire signaling system, including The RWG is still reporting, for example, "10 mg" instead of the actual amount of 15 mg, after having shifted the dosing piston so that 5 mg/KH more than intended are always dispensed. And the 1551... can only output something based on the motor computer "sensing" the RWG signal. Therefore, obesity determined by position in a control room cannot generally be measured by diagnosis.

Sounds logical... I hadn't considered that!!

Quote:

However, the critical situation arises in the idling range, where the engine computer is programmed with quantities of around 5 mg (?), and then "wonder" why the engine maintains idling speed despite apparently having 0 mg.

That's what I meant by the monitoring function, which seems to be missing in the STG.

Quote:

The jerky behavior may be due to some inappropriate control strategies that the engine computer employs in the face of such implausibilities

That's exactly what I meant with my post about the hysterectomy and the vote on the STG. The control system (STG) expects a specific operating behavior from the pump, but due to a defect (or wear and tear), it is no longer behaving as specified in the control system (STG).
Otherwise, I can't explain the effect when the tachometer signal is disconnected. When the tachometer signal is disconnected, these functions (jerk damping, throttle cut-off...) are disabled by the ECU (according to...) Bosch Service)
I even suspect that the vibration damping (torque damping) is responsible for this particular shaking.

ulf wrote:

However, a too high position setting cannot be determined by 1551 . . . because the electronics do not receive a message about the actual throughput volume. The RWG feedback only includes the indication of the signaling device.

Hello Ulf and Bertil,

IMHO, it should be possible to read a large setting via diagnostics.
To maintain a free-running speed of 900 min-1, a specific flow rate is required.
If the pump now delivers x mg/stroke more than indicated by the control element, the control unit will still attempt to reach 900min-1, i.e., it will reduce the flow rate until the engine is running at 900min-1.
At the same time, the amount of funding reported through the standard procedure decreases.
Therefore, an excessively heavy fuel injection setting should be apparent if the feed rate reported by the control unit is significantly lower than the normal value at idle speed (in my engine, it was approximately 2.2mg/stroke, but please don't rely on this, as I hadn't completely removed the box).
What do you think of my theory?

Hello, Rainer

Rainer K. wrote:

... Therefore, an excessively heavy fuel injection setting should be apparent if the feed rate reported by the control unit is significantly lower than the normal value at idle speed (in my engine, it was approximately 2.2mg/stroke, but please don't rely on this, as I hadn't completely removed the box). What do you think of my theory...?

Hi Rainer,

But Ulf also suspected this a few lines further down. Let's gather the amounts for free-running promotion together. There might then be clues as to whether to "fatten up" or "thin out".

[Translating...]

Hallo,

gute Idee, vielleicht findet man dann einen Zusammenhang zwischen Fördermenge bei Leerlaufdrehzahl (zwecks Vergleichbarkeit Licht + Klima aus, Motor auf Betriebstemperatur) und einer Ruckelneigung.
Werte für mein eigenes Fahrzeug sind aber nicht so einfach zu liefern, da mein Box-Zwischenadapter recht gut und wasserdicht in den Pumpenkabelstrang integriert ist, müßte ich für eine verlässliche Messung zerrupfen.

Bei allen Nicht-Box-Fahrern (also Serie/Chip) mit VAG-Com/1881 wären also die Werte von Meßwertblock 1 des Motorsteuergeräts bei Betriebstemperatur sowie Licht + Klima aus interessant.

Gerade habe ich mir das PDF zur Industriemotorinbetriebnahme angesehen, hier liegen die Sollwerte für die Einspritzmenge im Motorleerlauf bei 3 - 9mg/Hub ?!
Bei meinem AHF messe ich je nach Adaption zwischen 1,x und 3,x mg/Hub... vielleicht sollte ich doch mal ne Messung ohne Box machen.

Grüße, Rainer

Rainer K. wrote:

In my opinion, reading a large engine setting via diagnostics should already be possible. To maintain a free-running speed of 900 min-1, a specific flow rate is required. If the pump now delivers x mg/stroke more than indicated by the control element, the control unit will still attempt to reach 900min-1, i.e., it will reduce the flow rate until the engine is running at 900min-1. At the same time, the amount of funding reported through the standard procedure decreases. Therefore, a too-fat station setting should, in my opinion, be detectable if the throughput amount reported by the control unit is significantly lower than the normal value at idle speed

Hi Rainer

"In principle, you are absolutely right, but in practice, it is likely that things will be (somewhat) different. Even with the same engine, the actual amount of fuel injected to maintain 900 rpm will vary significantly from engine to engine.

As for causes, I'm thinking of factors such as the condition of the engine (wear/compression), the precision of the engine control (worn/stretched timing belt --> misaligned valve timing), the actual quality of the current fuel fill (variations in calorific value), the condition/age of the injectors, and even the condition of the battery (current charging requirements), the type of oil and engine temperature, and so on. And of course, the "final" manufacturing precision of the pump from the factory.

Overall, the range of displayed values is likely to be so large that it is difficult to confidently conclude that a particular positioning is excessive – provided that there are no "enormous" errors, such as a displayed quantity of only 30% of the usual value according to the repair manual.

[Translating...]Hallo erst mal an alle !

Ich habe bis jetzt auf diesen sehr informativen Seiten nur mitgelesen und auch schon sehr viele Tips zur Fehlerbeseitigung finden können.

Jetzt hänge ich genau an diesem leidigen Ruckelhema zwischen 1300 U/min und 2000 U/min beim Passat 66kw Tdi Motor 1Z 185000 km.

Ich poste mal den Messwertblock 1 gemessen mit VAG-COM.

Leerlaufdrehzahl

903 U/min

Einspritzmenge

2,6 mg/H

Spannung Geber Regelschieberweg

1,36 V

Kühlmittel

88,2°C


Ich werde in den nächsten Tagen eine neue Einspritzpumpe verbauen und hoffe dann ist endlich Ruhe.

Gruß Detlef

Hi Detlef,

I'm eagerly awaiting the results, like a coiled spring...

Quote:

Injection volume 2.6 mg/h Voltage Sensor, Actuator Travel, 1.36 V

Hi

Compared to the industrial TDI (AFD) pump, the pump may be too high.
These values at idle are 3 - 9 mg and 1.5 - 1.95 Volts.

A "simple" adjustment of the quantity control system might fix the problem for free --> see the link above in this thread or "DIY-Ruckelabhilfe" in the TDI error database.