Underground 1Z - Acceleration Pits

Hello!
My 1Z produces approximately 81 kW instead of the specified 66 kW. Since the chip tuning, I've been experiencing a wave-like acceleration, similar to Ulf's article.
/viewtopic.php?t=6529
However, within the entire speed range, there are only approximately 2 "acceleration valleys".
The two vibrations occur approximately at 3000 and 4000 RPM.

Unfortunately, I don't have a laptop that I can use to log in while driving.
Therefore, I just completed a diagnostic test and measured the pressure sensor's voltage during the process. (In my old 1Z, it was a separate component)
Sensor supply voltage: 5.1 V
When the engine is at full throttle and there are no vibrations, the voltage is approximately 4.9V.
When the vibrations occur, the voltage rises to a maximum of 5.04V and then immediately drops back down to 3V!!!

(relatively slow digital multimeter; the voltage may also be approaching its limit)
This is definitely noticeable, the amount of fuel injected is also decreasing (measured relative to the position potentiometer of the throttle lever).

Clearly, the boost pressure is very close to the upper limit of the sensor's measurement range. IMHO, this is the reason why different tuners specify the maximum power of the old 1Z engine at 110-112 hp. Around 115-120 hp.

And that is likely also the reason why I am experiencing a slightly stronger amount of smoke, as the air mass for the fuel injection amount is too small.

Unfortunately, the STG only has the "group0" and therefore I cannot read the torque and speed limits.

Do other drivers of older 1Z engines experience this problem?
Or do you have any ideas about what I can do about it?

wolfi_b wrote:

My 1Z produces approximately 81 kW instead of the usual 66 kW. Since the chip tuning, I've been experiencing a wave-like acceleration, similar to Ulf's article. /viewtopic.php?t=6529 However, within the entire speed range, there are only approximately 2 "acceleration valleys". The two vibrations occur approximately at 3000 and 4000 RPM.

I suspect a different cause than in the article, namely a correction of the boost pressure by the EDC, where the increased pressure apparently lies "at the maximum limit".

Your tuner probably failed (or is not capable) of making the rule characteristics more lenient, in order to reduce the corrections so much that the pressure only decreases slightly.

As a possible solution, I could imagine adjusting the wastegate lever towards a previous opening position = reducing the spring tension to shift the control point.

Also, there was also tuning software installed, which also had an acceleration boost. At approximately 3200 RPM.
I also have the old 1Z with an external fuel pressure sensor. Could I not also apply a kind of "10 cent tuning solution" to that in this case? It's also difficult to replace the boost pressure sensor.

Hi faz!
I've been waiting for you
Why did you uninstall the software again??

So, meiner Meinung nach ist das Problem der Ladedrucksensor. Aber 10ct Tuning wird da nichts bringen, weil der Drucksensor schon an der Grenze ist. One possible solution is the use of a different pressure sensor and a customized calibration curve.

ulf wrote:

As a possible solution, I could imagine adjusting the wastegate lever towards a previous opening position = reducing the spring preload to shift the control system's operating point.

I'm not quite following what needs to be changed, given my limited knowledge of control engineering.
But you are certainly right about the cause. I was wrong.

wolfi_b wrote:

Even with my modest knowledge of control engineering, I can't quite understand what needs to be changed.

Mine are also quite small and come almost exclusively from my electronics hobby projects (not from TDIs). . .
In principle, can modify the behavior and "swing tendency" of a control system by adjusting the operating point (or offset), but this is not guaranteed to be successful.

In my Polo, I might currently be experiencing something like this:
Due to overpressure up to ~ 1.6 bar (max. (Normal pressure is 1.3 bar) I had bent the VTG bar quite a bit during my vacation.
On the return journey from vacation on the highway, I was able to admire the LDA loading pressure oscillations of 0.1 bar or even slightly more (frequency ~ 3 Hz), not only at the maximum. Not just under pressure, but also at partial loads, for example at 1 bar or less.

Unfortunately, I don't know if the rule has always been in place, because I don't often observe the LDA and only very rarely drive on long BAB (Autobahn) stretches.
On the trip to vacation with the original VTG setting, nothing seemed out of the ordinary. However, since the vibrations don't occur reliably, this doesn't necessarily mean anything.

On my daily trips on village and country roads, the pedal position and engine speed often change too quickly, making it difficult to detect or even create vibrations.
I will soon make the pole even longer (the overhanging parts haven't become much smaller yet) and see what happens then...

Hi wolfi_b!
is ja krass, dass auf mich schon gewartet wird! If my girlfriend knew...

Regarding the tuning software:
I had the tuning done at around 160,000 km and have been driving it until recently, i.e. 245,000 km.
The main advantage was the earlier and very aggressive torque increase compared to the standard model, around 2100 RPM. Good power output up to 4000 RPM. The top speed didn't change much. I also found the quite pronounced "turbo lag" to be a drawback, which became quite noticeable when using the air conditioning. I simply can't get used to it. At low speeds, the software seems to be right at the limit of the compressor's capacity, and later, the turbocharger pressure sensor probably causes problems. The compressor is also a bit larger than that of the later 1Z model, which is why the torque maximum is also reached later. Also, also vibrations at low speeds and under partial load.
The trigger for me to now use the original system was the problem with accessing the MTSG. I was unable to do so with the VAG1551. I haven't yet tested what the situation is now with the original factory-installed control unit. But there's more to come. I just want to know if everything is okay with the engine.

Due to the pressure sensor: I thought that by making an electronic change, one might be able to enable operation with higher boost pressure, without the control unit noticing anything. Doesn't the boost pressure sensor also have an input for ambient pressure? Couldn't something be done there, perhaps? I think I need to take a closer look at this thing...

Hi faz
Yes, the new timeline is really nice

I also find the Russian accent annoying. But I don't have air conditioning, so it's probably not as hot as it is for you.
But I don't experience any stuttering, and I actually have access to the MSG even with my homemade adapter.

The ambient pressure is measured directly in the STG. The load pressure sensor measures the absolute pressure.
The serial pressure sensor is already at its limit, so it cannot be adjusted further.
As a solution, I was thinking of using a series software, larger nozzles, and a different boost pressure sensor to increase the boost pressure.

@ulf
Thank you for the tip. I'm going to try it out.

Where are you going to get another boost pressure sensor from?? Look, I don't know any vehicle besides the old 1Z that has an external boost sensor.
I'm also considering larger nozzles, but without increasing the boost pressure, as that would likely result in excessive soot formation

My car now has 250,000 km on it. Could the sluggish acceleration at high speeds (3700 RPM - x) be due to a partially clogged catalytic converter? While I can't personally vouch for it, are there any established benchmarks or data points I can refer to?

faz wrote:

Where are you going to get another boost pressure sensor??

For example, a Motorola MPX4250AP. It can operate up to 2.5 bar absolute. Then, only the initial voltage needs to be adjusted - done.

Hi,

Quote:

I mean, I don't know any vehicle besides the old 1Z that has an external boost pressure sensor.

All newer TDI engines (from ALH/ASV) apparently have an external sensor in the intake manifold, combined with the measurement of the intake air temperature. Someone had posted the voltage values before, and there isn't a significant difference compared to the MPX4250AP - perhaps it's even the case for some TDI devices, as Motorola explicitly mentions "automotive applications" in its datasheet.

Best regards,

Jan

That's great!

What about the test phase? When does it start?

I need to finalize my LDA model first, then we can proceed.

I checked the eCat:

The boost pressure sensor from the old B4 TDI was also found in the Audi 100 with 120PS and 115PS. Similarly, in the old 3er and 5er BMW with the 2.4td engine. And in the Peugeot 2.5td.

Why an external sensor, and later internally within the Mtsg? Or, according to Jan6K, the trend is now back to external?
Why, why? Are there any background details?

According to the label, the old 1Z has a Garrett T2 turbocharger.

Does anyone have a signal jammer?
I would like to check what the possible charging pressures actually are, without reaching the pump/stroke limit.

@wolfi_b
We should also check the compressor detection field, and also the airflow meter. It wouldn't be surprising if the LMM also reached its measurement limit. Otherwise, nothing really makes sense.

faz wrote:

The fuel pressure sensor from the old B4 TDI was also found in the Audi 100 with 120PS and 115PS engines.

I think, though, that they had 2.5 liters. Likely, the boost pressure wasn't that high either.
Could you measure the output voltage of your boost sensor when the accelerator pedal is fully depressed? (The middle line of the three-pole connector against ground). I would like a benchmark value with serial software.
I will now check the range of the flow meter.
A compressor detection field would be really interesting - doesn't Garrett have something like that?

They had a 2.5L engine, 5-cylinder. The block was also used in the T4 later. I took a closer look, they had the same boost pressure as the 1Z.

I could certainly measure the initial voltage, no problem. If you can wait until September 11th. I still have to take a few more exams.

There are already several types of compressor detection fields. I've only found turbochargers that are currently available.
http://www.turbocalculator.com/garrett-turbochargers.html
and here is the current Garrett catalog: http://www.turbobygarrett.com/turbobygarrett/images/garrett_inside/Garrett_Cat%207%2017%2013.pdf

I thought that maybe someone in the forum might have the information, as it's possible that the compressor was also used in older TD models. But I think that pressures of 1.2 bar should definitely work.