Turbocharger Problems: ALH Engine - What to Do?

Hello everyone,

The turbo boost control behavior of my ALH engine (only 50,000 km, manufactured in 2004) is SHOCKING me.

Approximately 330 mBar overpressure, approximately 150 mBar underpressure.

Handling deficiencies = zero; I can't detect either the over- or undershoot, and the air mass remains above the torque limit.

Should I be worried? I don't really want to start a complicated troubleshooting process.
I've found similarly poorly performing ALH (presumably referring to a specific product or system) in other threads.

I don't see any obvious defects in the hose, VTG (valve timing gear), etc. The VTG is easy to operate and doesn't jam anywhere, and there's no play in the linkage. The return spring on the canister is stronger than my thumb. When set to the basic setting of MWB 11, it moves quickly and smoothly...

What should I do? Should I just continue driving normally?

He also drove very aggressively.
'Check out a full-throttle acceleration test, approximately 1000 RPM each time, in both 3rd and 4th gear. Then, evaluate the throttle response (on a straight road, revving up to 2500 RPM).'
If you're not completely submerged in the water during the underswim, then everything is fine.

I don't see any obvious flaws either, but try the test as described above.

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He also drove very aggressively.

Driven dynamically?

Okay, so the image shows a normal view of the highway... accelerating from the on-ramp at approximately 1500 RPM (3rd gear) and then reaching 130 km/h, which is about 2900 RPM.

I'll try setting the speed to 1000 RPM in the 3rd and 4th gears tomorrow, although I'm skeptical about whether it will actually help.

Let's try asking it a different way:

Do you experience a loss of power, excessive soot production, jerking, limp mode, or error messages?


If the car is running normally, I don't see a need to do anything, because: never change a working system.

It's actually important that you start the test 'deep within the smoke suppression zone,' which is why you should use settings like 1000 or 1250. This gives the PID controller time to adjust (especially the I component). It's only for better comparability.
The ideal scenario for this test would be an overpressure of approximately 100-150 mbar, followed by a stable pressure reading from the top, ideally without any undershoot.
It's also important to know how long such a surge lasts.

The chargers are quite forgiving, but I don't currently see any specific problems with yours.

Malte1408 wrote:

The turbocharger boost control behavior of my ALH engine (only 50,000 km, manufactured in 2004) SHOCKS me. What should I do? Should I just continue driving normally? Just swap the two EPWs to see if the N75 is the cause.

It will only take some time, and it will expand the basis for further decisions.

Okay, I'll give it a try.

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This allows the PID controller time to adjust (especially the I component)

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So, actually, I thought that in these lower RPM ranges, the boost pressure is only controlled. That's also why there's the "pre-control map," although it's not really a pre-control in the true sense. It's more like a mode switch; a "control according to map" / regulation system.

I highly doubt that it's programmed in such a simple way that I-components could disappear in areas where it's difficult to achieve stable regulation. I believe that without limiting, reducing, and switching I-components, it would be impossible to regulate such an unstable process.

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Simply swap the two EPWs to see if the N75 valve is the cause.

It only takes a little time, and it expands the basis for further decisions.

Yes, I also skimmed something that said the Christel-ALH } isn't that great either. I might get a new N75 tomorrow (I have the 1J...). } It doesn't cost that much, and I only have to disconnect three hoses. }

'Boost pressure is only controlled in lower load/RPM ranges, which is correct. However, when entering overrun mode, it is regulated.'
In the control system, only the pre-defined characteristic curve is used. In the regulation, 's' is the sum of the pre-defined characteristic curve and the PID parameters. Indeed, the parameters are 'windowed,' as you correctly identified.
Ultimately, this test is quite suitable for evaluating the quality of the rules. That's the main point.

Okay,

I got a new N75 and logged the data again. It doesn't look much different, although the overshoot might be slightly less pronounced.

I also followed DieselWiesel's suggestion and recorded logs starting at 1000 RPM, and for the 3rd and 4th gears.

I think I'll leave it as is. It seems that's just how it's designed to be within the charger's tolerance range.

What type of loader does the ALH actually have? And what are the general differences between the ALH and the ASV with 81 kW?

Does anyone know what cycle time the boost pressure control system operates on? Is it 50ms?

Is this an EDC17? The task execution time should ideally be faster than 50 ms.

Overall, the image isn't quite as nice, but it's as expected. It would be interesting to see other vehicles to have a comparison (I personally can't provide any, as I own an Opel ), but a VL acceleration in 3rd or 4th gear is very comparable.

To better assess the situation, we still need information about the amount of smoke and the smoke containment system, specifically whether the smoke containment system at the lower part of the engine protrudes into the rotating parts. This can often be felt (as a pulsating torque), especially after a certain amount of use, when the mass airflow sensors become dirty and provide inaccurate readings.
Furthermore, this can be used to determine when the smoke limit is exceeded (based on the load and mass airflow sensor readings). A good value would be around 1500 RPM in the 4th gear.

Can you please include the measurement parameters?

At least the VTG isn't moving 'too fast,' as that would also be noticeably negative, due to the significant change in the ejection resistance.

Edith: What looks strange is the dead time in the duty cycle. Normally, the charger should retract immediately when the pedal is pressed, right? Is this really the control signal for the charger, or something else?

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Is this an EDC17

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For goodness sake, EDC15...

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specifically whether the smoke limiter on the lower blade enters the rotating part

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No, it doesn't. I used to log that, but in the current logs for a higher sampling rate, it only shows MWB 11.

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A good value would be around 1500 RPM in the 4th gear.

It's roughly like that. You can also see it in the boost pressure log; when the actual value is above or below the target value, it's definitely out of the smoke reduction range. In fact, it starts to go out a little earlier.

What looks strange is the dead time in the duty cycle.

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Da ist keine Totzeit in der Stellgröße, der Lader IST schon "gezogen", 24% ist maximale Ansteuerung der VTG auf zu also max. Ladedruck. The VTG is always fully engaged when it is not actively being used.

Can you please add the measurement parameters?

I've added 2 more logging trips where MWB 8 is included. However, it's quite a long trip, somewhere. So, if you'd like to pick out the interesting spots yourself,

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Is that an EDC17?

What looks strange is the dead time in the duty cycle.

Da ist keine Totzeit in der Stellgröße, der Lader IST schon 'gezogen', 24% ist maximale Ansteuerung der VTG auf zu also max. Ladedruck.

The VTG is always fully engaged when it is not actively being used.



Okay, I've learned something new. It's displayed in reverse, got it .
At Opel, everything is the right way around .

Based on my assessment, I would now discharge the patient as healthy.

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Well, I've learned something new. It's displayed in reverse, all right

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By the way, with EDC16, it's actually the opposite, just like you thought.
I don't know about EDC17, maybe they reversed it again .

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At Opel, everything is going the right way

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Well, they also have sealing rings for the cross-bore, and they let the VP44 run dry.

For this, there are Bosch VE conversion kits - just one cable is enough .