Performance Issues: Why It's Late

Hello.

I had an engine failure in my A4 2.0 TDI BRD with 170 horsepower.
Finally, I found a used engine and installed it.
The engine started immediately. It seems to be running well enough.
Just to clarify, while my "old" engine delivered its full torque at 2100 RPM, this new engine only achieves that at 2400-2500 RPM.

You can tell that the turbo provides good boost even from 2000 RPM, but not at full power.
I once recorded data for MWB 011 006 003 while it was in 3rd gear and running at full load.
Please let me know if you need any more MWB (material waste bins).

I took almost everything from the new/used engine.
Turbo, EGR valve, intake manifold flap, charge air control valve, EGR control valve.

So, I would still have some spare parts .

The intake manifold, EGR valve, exhaust cooler, and pipes, etc., were previously removed and cleaned.
I've also checked the vacuum hoses again. They seem to be in good condition.

Perhaps someone among you has an idea about what might be causing this?

Have you checked if the VTG container seals completely and creates sufficient vacuum?

, I also suspect insufficient vacuum. The actual boost pressure value is significantly lagging behind the target value.

Check if all the vacuum hoses are properly connected and if any plastic connectors have been cracked (and leaking) due to handling. Does this engine have swirl flaps in the cylinder head? If so, check the vacuum actuator for those flaps to see if it's sealed or if the membranes are torn.

PS: In measurement block 8, you can see the quantity limits. I suspect that the limit for air mass is too low, because the engine is building up boost pressure too slowly.

Best regards, Rainer.

Hi.
Thank you for the tips.
I'm going to take a closer look at the vacuum system.
I already have all the vacuum lines and other components doubled. Therefore, I might be able to swap them around if needed.

Nothing will happen before Tuesday. I don't have time before then, or the car isn't here yet.

Yes, there are swirl flaps. They are located in the intake manifold. I cleaned them while cleaning the intake manifold, and they move freely.
I will also check the can on Tuesday.

Have a nice Sunday.
Regards,
Bolzer.

It's also interesting to note the wave on which the flaps are mounted.

Where they come out of the intake manifold, they sometimes leak, causing a loss of boost pressure.

The vacuum sensor for the flaps is easy to test -> just connect a syringe to it.
(Or I think they're taken care of even when idling, so just attach/detach the hose.)

m;

Hi.

I finally had a chance to thoroughly inspect the vacuum system.
The pump generates approximately 0.65-0.7 bar of vacuum pressure.

The vacuum hoses from the turbocharger, the exhaust gas recirculation system, and the swirl flaps are okay. They are holding vacuum.
The lines are also okay.

The throttle valves are briefly closed during startup and then return to their default open position. When the accelerator pedal is pressed, they are briefly activated repeatedly, and when the accelerator pedal is released, they remain closed until the idle speed is reached.

The coil seems to be okay as well. At least, when I spray it with brake cleaner, there's no reaction.

I hope I haven't forgotten to check anything.
Regards,
Bolzer.

Is the turbocharger pressure line itself sealed?

Best regards, Rainer.

Hi.
Based on my initial inspection, I can say that the boost pressure system appears to be leak-free.
I'll try them out tomorrow. Then I can say for sure.
Regards,
Bolzer.