Demand for wastegate turbochargers and boost pressure control

Hello everyone,

It's been a long time since I've written here again.
I couldn't find any entries for my questions.
I thought a while ago that the problem with the black smoke coming from my car would be resolved. It was, or is, unfortunately, not the case.

I am interested in the following:
I have an A6 C4 with a 140 hp engine. It has a turbocharger with an internal wastegate.
Can you hear a hissing sound if the wastegate is leaking, even just a little?

And then it should be the case that, with an increased injection quantity, the boost pressure also increases due to the higher combustion pressure... so where is the sensor or probe for that located? Or, to put it another way, how is this regulated?
There must be a sensor somewhere for the boost pressure... or does it all just work through the solenoid valve?

I don't use any engine tuning chips or other modifications. But I really want to get rid of this smoke. And maybe this arrangement isn't working properly.
By the way, the AGR is "sealed."
Measurement data block, OK.

Thank you for your efforts, and see you soon.

Regards,
Wool.

Hi,
He definitely has some rules in place. There have also been a few threads about it. The pressure source is located in front of the injection molding machine, under a cover.

I don't hear anything coming from it. From the outside, it should always appear sealed. At higher speeds and loads, the wastegate is always more or less open.
I once had a small hole in the pressure hose between the coolant reservoir and the intake manifold. The smoke was billowing dramatically.

Hi,

I understand that there's a regulation system in place. But how does it determine the current boost pressure in order to adjust it accordingly via the solenoid valve? I'm familiar with solenoid valves. That has already been tested and is okay.
I read an old thread and bought a cheap pressure gauge from Obi. Now I'm going to build an adapter for it and then test the boost pressure. Let's see if this one is correct too...
And then I'm going to disassemble and verschandeln the suction bridge.
I would rule out a hole in one of the tubes, because it sometimes doesn't smoke at all. At least, not in a way that's visible to me as the driver. I will still check it, though.
If there are any more tips available... please share them. I am grateful for any suggestions.
A solid foundation of knowledge is definitely present.

Thank you, and see you around.

Best regards to everyone.
Wool.

Hi Wolle,

As Christians previously reported, there is a sensor used to measure the pressure, which provides the engine control unit with information about the current boost pressure.

Quote:

The pressure source is located in front of the injection wall, under a cover.

The engine control unit (ECU) contains a lookup table that stores the desired boost pressure for each possible engine operating point. The control system compares the desired pressure with the actual pressure (resulting in an error signal) and controls the solenoid valve (and thus the wastegate) accordingly. Factual circumstances.

Quote:

... because he also doesn't smoke from time to time.

That sounds like a stuck or clogged EGR valve that sometimes manages to close properly, but sometimes doesn't.
While I'm not familiar with the 5-cylinder TDI engine, it shouldn't be difficult to locate the valve on the intake manifold. It has a distinctive membrane manifold and still needs to be connected to the exhaust manifold.
Just take everything apart and verschandeln it.

Regards,
Alex.

Hi Alex,

donalexo wrote:

That sounds to me like a difficult-to-operate, clogged EGR valve that occasionally manages to close properly, but sometimes doesn't. While I'm not familiar with the 5-cylinder TDI engine, it shouldn't be difficult to locate the valve on the intake manifold. It has a distinctive membrane manifold and still needs to be connected to the exhaust manifold. Just take everything apart and verschandeln it.

Wool wrote that his AGR is "clogged" .

wolle wrote:

By the way, the AGR is "sealed".

Sissu Alex.... Bertil read it carefully... *especially cheeky grin*
You're right about the AGR... but it's already... well, it's clogged... hehe.

But you're talking about a sensor. Where is it, then? That would be very interesting to me...
I'm currently preparing a pressure gauge to monitor the boost pressure while troubleshooting.
I also need to change the oil soon. Let's see if there's coolant in the oil again. I particularly like the hose that supplies pressure to the solenoid valve.
For your information: In the LLK (likely referring to a cooling system component), I once had so much condensation that it sealed off that hose (the hose is located at the very bottom of the LLK). However, it has now turned out that this has only happened once so far... so far.
Well... let's wait and see.
I'm always grateful for new tips...


Regards,
Wool.

wolle wrote:

But you're talking about a sensor. Where is it, then? That would. I am very interested in...

Hey, then read what has already been answered to you in this thread twice.

Quote:

The pressure source is located in front of the injection wall, under a cover.

If you can't find it, then ask again, clearly and directly.

*GRUMBLE*
Ulf.

Thank you, Ulf .
@wolle: I described this about half a year ago, and I don't want to repeat myself. I'm just a bit lazy.

I'm glad things are going so well here.

@Ulf: What's with all the "grumbling"?


"There must be a sensor somewhere for the boost pressure, or does everything just run through the solenoid valve?" "The quick brown fox jumps over the lazy dog."
Okay, no problem. Just provide the text you want me to translate.

Is the question not clear enough? There is no sensor or anything else under the cover on my injection molding machine! The solenoid valve is also open... if that's what you meant, I just didn't understand it. Things happen... (and I definitely won't apologize for that!!)
DOUBLE RUMBLE

Even though it may seem like it... I'm NOT angry or anything like that. But I also have an opinion.


@christians

"I couldn't find any entries related to my questions." "The quick brown fox jumps over the lazy dog."
(And again... sorry, I'm not familiar with the copy and paste function.)

Hey man... that wasn't an excuse!!!

But I'd still like to explore further.


Of course, I "found" the solenoid valve. I'm familiar with that as well. If that's what you meant... it's not covered by anything in my setup.


Guys!!! I definitely have some basic knowledge, but I'm not a professional. Otherwise, I would be able to solve this problem without having to ask any questions here.


I wouldn't rule out the possibility that I'm being a bit slow right now... I'm only human, after all... but... I'm currently drawing a blank. Sorry.

wolle wrote:

@Ulf: What is all this "GRUMBLING" supposed to be?

How would you react if someone clearly ignored a question after you had already answered it twice? That's how it affected me.

Quote:

Quote: There must be a sensor somewhere for the boost pressure, or does everything just run through the solenoid valve? "The quick brown fox jumps over the lazy dog." (sorry, I don't know how to copy and paste)

Highlight the passage and then click the "Quote" button above.

Quote:

Isn't the question not clear enough? There is no sensor or anything else under the cover on my injection molding machine!!! The solenoid valve is also open... if that's what was meant, I just didn't understand it. It might happen sometimes... (and I definitely won't apologize for that!!)

Ah, and why didn't you write that (so clearly) earlier?

I don't know your engine either, but it should have a pressure sensor somewhere. Most likely not in the same housing as the solenoid valve.

Three cables must connect to the sensor, and a thin tube must lead to it, branching off between the coolant reservoir and the engine.

If the sensor is located in the intake manifold (or at the outlet of the intercooler), then the aforementioned thin hose is not needed. Then only 3 cables run from that point - or 4, if it's a combination sensor for pressure and temperature.

Hi,
I am not personally familiar with the AEL, but it is said to be very similar to the AAT. The AAT houses, among other things, the magnetic valves for EGR and LDR, as well as the aforementioned sensor, all under a cover. However, the AAT in the Audi 100 does not have a thermally conductive enclosure. That could at least lead to a different perspective.

You can also view all the posts of a member. Since I don't write excessively, this is a reasonable approach.

@Ulf

First, think about the explanation with the copy function.

It's certainly quite rude when someone ignores a response. But then, in this case, I wouldn't even need to ask in the first place.
But from that perspective, I can definitely understand your reaction.


I'm planning to remove the intake manifold anyway, for cleaning purposes. Then I'll have some free time and can look for a sensor.

I may get back to you later.


@christians

I've also heard that the AEL is quite similar to the AAT.

"However, the solenoid valve for the EGR system is located on my air intake manifold, near the mass airflow sensor. The solenoid valve for the lambda sensor is located on the fuel injector rail." I'll look for the pressure sensor.
Maybe I'll finally get the boost pressure gauge installed this week. Let's see what I can fit into my schedule.

I'm gradually going through your old posts. Let's see...



Thank you, but that's all for now. I will get back to you if any further questions arise.


Regards,
Wool.

Hi,

wolle wrote:

He has a turbo with an internal wastegate. Can you hear a whistling sound if the wastegate, even just a little bit, is leaking?

Do you hear something? It shouldn't be making any noise. Along with smoke and "condensation," that sounds like a leak in the system. There's no condensation in the refrigerant, at least not enough that you would need to drain it. It's probably coming from outside (rain/splashing water). This black, oily substance is normal, provided the amount is within acceptable limits (blow-by gases mixed with oil mist from the engine that pass through the crankcase ventilation system and into the intake manifold).
Okay, please check the coolant level and the hoses/connections for any leaks.

Best regards, Uli.
[/quote]

Hi Uli,

I don't hear anything. That was just a line of thought.
I thought the wastegate only opens in emergency situations. The boost pressure is supposed to be regulated by the solenoid valve. However, I read in this thread that the wastegate is likely open to some extent at higher RPMs. That wasn't clear to me.

I will thoroughly inspect the hoses as part of the intake manifold cleaning process. And of course, we'll verschandeln up together.

After that, I will monitor the boost pressure for a few days. Maybe I'm looking in the completely wrong place...

Regards,
Wool.

Hi,
While it's not directly related to the topic, I'm curious: What type of air flow or mass measurement system does the AEL use? Is it something like a throttle valve, similar to the AAT, or does it use a hot-wire or hot-film sensor? If there's a valve, it's located on the side of the air filter housing. It's quite heavy, and the spring that keeps it closed is also very strong. So completely different from the surge tanks of the older K(E)-Jetronic systems.

@christians,

I'm not sure, but I think this is another design similar to the one in the AAT. If it doesn't rain tomorrow, I'll work on the car. Intake manifold cleaning, pressure hose cleaning, visual inspection, rear brakes, etc., etc... Then I'll take a look and let you know if it's really the case.

Yesterday and today, it ran absolutely great again.

Regards,
Wool.