T5 Performance Issues: Troubleshooting Guide & Tips

teileklaus wrote:

Here is the first attempt after CSV conversion

Hi,

Did you run the conversion in reverse?
When I open this file with Excel, I get the usual block of numbers on the left edge of the spreadsheet...

My own logs, on the other hand, can be opened perfectly well as pristine .csv files (with each value row having its own column) and saved as .xls without any modifications.

You killed the log!

"all", "and", and "." have been converted to ";".

Therefore, all the numbers are wrong because there are only integers, but more than columns.

Please just provide the data in a .csv format, or even better, an .xls file with nice images.

Sure, here is the translation of the text from German to English:

"m" translates to "male" in English.

I managed to salvage what could be saved.

"The turbocharger pressure is making the monkey... maybe there's a leak?"

Hello,

That's right, the LD cannot be properly constructed.
Since the LM is also showing significant fluctuations, something behind the turbocharger seems to be leaking intermittently. On the VTG's turbine wheel, you can see that the turbocharger is clearly trying to build up boost pressure.

At high speeds, the lambda value no longer fits within the acceptable range. Therefore, you enter smoke reduction mode, during which the lean-burn (LD) system reaches its target value.
However, this requires closing almost 40% of the throttle valve (VTG), which is a very large angle at 4000 rpm.


Best regards, Jochen.

Thank you to all three of you.
Could it be that the LL hoses with spring clamps are not able to withstand the pressure because, when one of the hoses initially failed, a screw clamp was installed by a qualified mechanic?
Tomorrow I will check out the available connections/routes.

What makes me uncertain is that the performance has been too low since delivery (at the time, the suggestion was to break it in first - the DPF and all-wheel drive also take away some power, etc.).
(Comparison to another T5 [although with rear-wheel drive])
Difference of 140 (km/h) when driving slower at 10 km/h, and a further decrease due to an additional 30 kg of weight. Maximum speed: 175-180 (km/h).
approximately 190
I'm going to have to solder my charging circuit .

Jochen_145 wrote:

Da die LM ebenfalls deutlich schwangt, scheint irgentetwas hinter dem Turbo, nicht immer dicht zu sein.

Sehe ich etwas anders: beim Abblasen über ein Druckleck steigt gleichzeitig der Volumenstrom durch den LMM, d.h. die Trübung dürfte nicht gleichzeitig mit dem LD einbrechen. DaShe does, though.

Therefore, there is either no pressure leak, or the turbidity is calculated using the LD (instead of the LuMa). Unfortunately, there are now also engines like that, for example, the 1.9L 96kW EU4 engine called BLT.

Quote:

At high speeds, the LM no longer works correctly. Therefore, you enter smoke reduction mode. Wherein the LD reaches its decreasing target value.

Consequently, it seems that the intention is for the engine to reduce emissions "at maximum speed."

I see something differently: when a pressure leak is detected and the system shuts down, the volumetric flow through the mass airflow sensor (MAF) increases simultaneously, meaning that the drop in opacity should not occur at the same time as the shutdown (LD). However, it does.
Hello Ulf,

ok, approved

Therefore, there is either no pressure leak, or the turbidity is calculated using the LD (instead of LuMa). Unfortunately, there are now also engines like that, for example, the 1.9L 96kW EU4 engine called BLT.

It's possible that the same approach was used for the 5-cylinder engine with Euro 4 emissions standards.

@Rainer
We absolutely need the 'download MSG file' function in VAG-Com so that we don't always have to guess.

Therefore, it is likely intended that the cloudiness will decrease 'at the top end' of the engine's performance range.
This would be consistent with the liquid crystal-dependent turbidity.

What do you think about the VTG control?
I find these to be much too tightly sealed, which is why I'm considering the possibility of a leak.
Or does the 5-cylinder engine have such a small turbo that the variable turbine geometry (VTG) needs to be constantly closed to generate enough low-pressure boost?

Then the problem might simply be due to a sluggish turbocharger control or a faulty variable geometry turbine (VTG), although this usually only occurs within certain operating ranges.

Best regards, Jochen.

Jochen_145 wrote:

What do you think about the VTG control? I find these to be much too tightly sealed, which is why I'm considering the possibility of a leak. Or does the 5-cylinder engine have such a small turbo that the VTG (Variable Turbine Geometry) has to be closed so much to even build up sufficient boost pressure?

I find it "not too bad" because the actual boost pressure is somewhat symmetrically around the target value, meaning the TV (Turbine Speed) requirement isn't miles away from the VSt (Wastegate Spring Constant), as would be the case with a large pressure leak.
Even a small, permanent leak is not entirely ruled out. To check this, you would need comparison values from the MWB10 logs of the same, intact engine .

Furthermore, here (unlike most 1.9 TDI engines), a high TV value corresponds to a high load demand, and vice versa. While the theoretical TV requirement should decrease with increasing engine speed, this is often not very pronounced depending on the specific engine code (see, for example, the VSt line of the ALH Ibiza in the thread about load behavior).

Quote:

Then the whole thing might simply be due to a sluggish turbocharger control or a jerky VTG (Variable Turbine Geometry), because actually, this behavior only occurs within the areas of large adjustment ranges...

That's also my idea.

I tried again to create a comparison log for another T5 and made a chart, but unfortunately it's still missing a legend and isn't from the "10er" series.

Hello, after today's emergency stop (due to the LD limit being exceeded), a new LDR valve was installed, and during the test run, it was reported that:
Okay, now he's much calmer again.
I once tried to log something, but I can't seem to set up my chart because it says "array not allowed" or similar.
In my opinion, the somewhat tired impression remains.
"Edit: Am I correct in saying that there is still room for improvement, both in terms of increasing the amount of diesel fuel injected and in optimizing the torque limitation, to further reduce emissions?"
We'll get feedback again tonight regarding the driving performance.

The performance is almost unchanged, possibly with a slightly better response at low RPMs.
In the upload section, I have uploaded files named "3-8-11" and "7-8-11".

"Edit: If the old LDR valve was stiff, it would explain the first problem I encountered when the hose came off (overshoot?)."

The file "LOG_Nef,05.02.08,nachTV-ern..csv" looks fine to me – except for the oscillations up to 21 seconds, but those don't really limit the power output much.

If the N75 valve is okay, then the only other likely culprit is a stuck VTG (Variable Turbine Geometry).

ulf wrote:

If the N75 is okay, then the only other likely cause is a stuck VTG.

Below, regarding the undershoot/overshoot values, yes.
If the maximum power output is limited due to a malfunctioning or missing VTG (Variable Turbine Geometry), wouldn't the boost pressure remain below the target value?
I'm increasingly inclined to believe that the results we see are a deliberately programmed and manipulated outcome.
If the vertical tail group (VTG) fin were adjusted in the correct direction, would that cause even more oscillations?

teileklaus wrote:

If the maximum power output is limited due to a malfunctioning or missing VTG (Variable Turbine Geometry), wouldn't the boost pressure be lower than expected?

That's correct - and the torque would have to be below the rated engine speed.

Quote:

The more I believe in a deliberately programmed, tired performance result,

. I see it that way too. Do you have any comparisons to other vehicles of the same type?

Quote:

If you were to change the angle of the VTG rod in the right direction, would that cause even more oscillations?

If you shorten it, probably yes.
Possibly, a slightly longer dwell time could reduce the tendency to oscillate – but it would likely also make the acceleration less crisp.

@ Ulf

teileklaus wrote:

... it had insufficient performance since delivery (at that time, the suggestion was to break it in first; also, the DPF and all-wheel drive could help...). (Comparison to another T5 [although with rear-wheel drive]) Difference of 140 (km/h) when driving slower at 10 km/h, and a further reduction with an additional 30 kg of weight. Maximum speed: 175-180 (km/h). approximately 190

.

teileklaus wrote:

(Compared to another T5 ( however, with rear-wheel drive), the difference is that it's about 140 km/h slower over 10 km and weighs 30 KG more.) Maximum speed: 175 - 180. loosely 190

. Well, the big unknown in the comparison is with the 4WD... I have no idea how much dynamic performance and top speed it costs on the T5.
A manual could certainly provide some guidance.

Otherwise, I can only refer you to the specialist for performance issues...