VAG-COM: Troubleshooting "Power Loss" Error Code 1Z

I have read all the threads about this topic in the forum, but I'm still stuck.

I followed Ulf's instructions (Systematic Troubleshooting...), and the mass airflow sensor (MAF) is definitely okay (I already have 3 of them). The wastegate valve (N75) is new and has power. The vacuum hoses are also new, including those in the control unit. The intake manifold is sealed, the exhaust system is fine, the EGR valve is also sealed for testing purposes, the turbocharger boost compensator works perfectly with a hand pump, and the wastegate valve moves freely, but...

My boost pressure is approximately 1/3 lower than it should be. I measured this with a pressure gauge (approximately 0.5 bar), and the diagnostic report from VAG-COM is attached.

All other measurement blocks are within the normal range.

Power loss in the 4th and 5th gears starting around 3000 RPM.

Control unit writes.

Error code 00575.
Intake manifold pressure.
Rule difference.
sporadically

Do I really need a new turbocharger? Or does anyone have any other ideas?

Audi A4, engine code 1Z, year of manufacture 1995, mileage 185,000 km.

Thank you in advance.

Hello, please check the vacuum hose on the engine control unit to see if it has slipped off or shows signs of abrasion.
Best regards, Nobi.k.

I already checked it today, but unfortunately, nothing is missing from the hose.

Hi,

Your boost pressure (less than 1300 mbar absolute) is essentially "non-existent." However, you did measure the boost pressure correctly, right? Meaning you were driving at full throttle and not just measuring it in the garage?

You either have a pretty big leak somewhere between the turbocharger and the engine, or the wastegate on the 1Z isn't closing properly, or the turbocharger is completely broken (oil consumption?).
Or you might have such a small amount of fuel injection that the turbocharger can't build up any boost, for example, due to a faulty mass airflow sensor (MAF).

Quote:

The Westgate flap is easy to operate.

Hopefully, the wastegate isn't too loose.

Best regards, Rainer.

I measured the boost pressure while driving at full throttle in 4th and 5th gear (currently achieving 140 km/h in 5th gear).

There's a slight oil film around the charger, but my Westgate moves without any resistance.

LMM is okay, I also tried it with the diode.

I'm going to try getting a charger tomorrow, hopefully it will solve the problem. Thanks for your help.

Best regards, Heinz.

Hello Heinz,
...my Westgate moves without resistance.
If you haven't disconnected the pressure vessel, I would suspect it might be a 'dead' or non-functional unit.
With a sealed and undamaged can, the wastegate is difficult to adjust without causing discomfort or pain when using bare hands.
Move fingers.

Best regards,
Rudi

hello rudi

'Of course, I disconnected the pressure sensor from the Westgate, as I mentioned earlier, I tested the sensor with a pressure pump, and I manually operated the Westgate valve, but still, thank you.'

I'm not getting a used turbo to test until the end of the week; I hope it solves my problem.