Golf 3 TDI: Excessive Smoke & Power Loss?

Good day, everyone!
I have a question. I don't know much about engines at all. I'm a complete beginner.
I drive a Volkswagen Golf 3 TDI with 90 horsepower, manufactured in 1994.
'Some time ago, the problem started where the car began to stutter in the mid-range of the engine speed (around 2,000 RPM). Additionally, there was a slight loss of power at top speed.'
Otherwise, everything is fine. The mass airflow sensor and needle valve lifter are okay. The air and diesel filters are also new.
Now, another problem has arisen: the car is extremely popular with Russians.
I haven't done any chip tuning. So, that's not the reason for it.
In addition, the performance has dropped significantly (it's not possible to achieve scores above 160), and during acceleration...
A loud whistling sound is coming from the engine compartment. It sounds like it's coming from the turbocharger.
The error memory is clear, and VW couldn't directly tell me what the problem might be.
They just suggested that I could replace the turbocharger myself, at my own risk.
However, they are a bit too risky at a price of 450 €.
Würde mich freuen, wenn mir da jemand Tips geben kann, woran es liegen könnte. WI would be happy.
Thank you in advance.
Best regards,
Michi.

Hello Michi!

Please try using the search function with the following terms:

AGR, AGR valve, disable AGR.

By the way, the turbocharger itself could also be a strong contender.

Regards,
Alex.

Ah, that was a really good tip.
I've already found something, and it seems quite plausible to me.
I would much rather have a faulty EGR valve than a broken turbo.
Unfortunately, simply blocking the EGR valve or disconnecting the connector for the EGR control valve is not enough, as I won't pass the emissions test with that modification.
'Still, it's a good way to analyze errors. I'm now looking for someone who can show me where to find this part (as I've already said, I'm a complete beginner) and I'll try connecting it.'
I'll let you know when I have more information.
Thanks in advance, Alex!

Could you please check the charge air cooler for leaks?
CAUTION! Even the smallest cracks can expand significantly at 1 bar of pressure...


CLICK


CU Gremlin.

Also habs gerade mal mit dem agr probiert. Einfach mal Stecker abgezogen und losgefahren. Result: Nothing!
After that, I put the plug back on, disconnected the vacuum hose, and screwed in a bolt. Well... it seems like the performance is better. However, it's still producing a lot of smoke.
'Quick question: Doesn't black soot more likely indicate poor combustion? If the EGR valve doesn't close properly, wouldn't unburned, excess diesel be expelled? This, in turn, would result in white smoke.'
Or am I misunderstanding something?

Next question. If I disconnect the vacuum hose and screw in a screw instead... what guarantees that the EGR valve is closed? It remains in the state it was in when I disconnected the hose, doesn't it?

Sorry for my dumb questions...

Hi Michi!

Quote:

If I disconnect the vacuum hose and screw in a screw.....what guarantees that the EGR valve is closed?

Niemand! Wenn das AGR-Ventil hängt und nicht mehr völlig schließt, dann bringt das Abziehen des Unterdruckschlauches gar nichts! Da hilft nur die "Blechlösung", also das mechanische Verschließen der Verbindung zwischen Abgaskrümmer und Ansaugbrücke. Dann hAre you sure?

Quote:

So, I just tried something with the AGR valve.

I simply unplugged the connector and started the car.

Quote:

The result: Nothing!

Could you please elaborate on that statement?



}Small question: Doesn't black soot rather indicate poor combustion? If the EGR valve doesn't close properly, then unburned, excess diesel is blown out. This, in turn, results in white smoke.
Or am I misunderstanding something?
}

Soot always indicates that there is insufficient oxygen available for complete combustion, meaning a lack of air. There can be several reasons for this. For example, if the EGR valve does not close properly, a bypass is created around the engine, directly from the intake manifold to the exhaust manifold. The air mass is registered by the mass airflow sensor (MAF), but only a portion of it enters the engine, so the injected fuel amount is too low in relation to the actual air mass. The result is black smoke and a loss of power.
A practically identical effect occurs when there is a leak in the charge air cooler system. You should inspect all connections and the charge air cooler itself for oil-soaked areas, as this is an indication of leaks.

The fuel injectors could also be worn out, which would cause poor atomization of the fuel in the combustion chamber. In this case, while the air mass might be correct, the surface area of the fuel droplets would be too small for complete combustion. This can also lead to black smoke and a lack of power.
Could you please tell me the mileage of your car/engine? I believe your engine code is 1Z, right?

Have fun searching!

Regards,
Alex.

Yes, the engine code is 1Z.

The engine now has over 305,000 miles on it. That's quite a lot.

I meant the plug like this:

The vacuum hose runs from the EGR valve to a box with a connector on it, and from there it continues into the air intake manifold.
The technical article about the AGR system states that pulling out this connector has the same effect as blocking the vacuum hose with a screw.
However, this will then write an error code to the error memory.



If I disconnect the vacuum hose and screw in a screw... what guarantees that the EGR valve is closed?


Niemand! Wenn das AGR-Ventil hängt und nicht mehr völlig schließt, dann bringt das Abziehen des Unterdruckschlauches gar nichts! Da hilft nur die 'Blechlösung', also das mechanische Verschließen der Verbindung zwischen Abgaskrümmer und Ansaugbrücke. Dann hAre you sure?


A master mechanic from a specialized workshop told me the same thing. I'm going to sit down with my cousin this week to try out the metal solution. If that doesn't work, I suspect it might be the turbo, the fuel injection system, or the intercooler.

Hello Michi...

I suspect there might be a hole or crack in your charging system... the loud whistling sound would be a sign of that, in my opinion (if you haven't heard it that loud before).
Another thing is that your intake manifold might be blocked... however, in that case, it shouldn't be difficult to start, but rather it would just lack power... I experienced something similar with my Gal.

Did your VW dealer not perform a dyno test? That would be a good way to check the turbo boost pressure!

But I would check your charging system.


Best regards, Mike.

http://www.cheesebuerger.de/smilies/verbluefft/60.gif

Problem gelöst. Nachdem ich bei diversen Werkstätten war, und mir keiner wirklich helfen konnte, hab ich endlich das Problem gefunden. Ein Teil vom Ladeluftschlauch hatte an der Unterseite (also nicht sichtbar) nen ziemlich großen Riss abbekommen. Ca4 cm.
With the engine running, you could immediately feel a draft if you held your hand there. It's unbelievable that VW wasn't able to detect the crack. Well, now my 90hp TDI is running at 190 km/h again and purrs like a kitten.

To be honest, I'm just wondering why I'm even bothering to write anything here right now...

See the 4th post in the thread...

CU Gremlin.