Passat AFN: Slow Performance - Dyno Test Results

Hello everyone,

After my OBD2 tester arrived today, I immediately...
I conducted a test run and obtained a surprising result.
For your reference, my issue was a perceived lack of torque.
in the lower RPM range (below 2,200 RPM), and I was expecting...
Slow boost pressure build-up suspected. Here's the diagram.
(Acceleration in 4th and 5th gear up to approximately 200 km/h according to the speedometer on the highway).

http://www.informatik-consulting.de/kunden/VAG-COM/VAG-COM28-11-02.gif

The pressure build-up is fine and even slightly ahead of the target value, with a small overshoot. However, what surprised me was the pressure behavior above approximately 3300 RPM: it was about 20% above the target value (the external pressure was 1000 mbar), and the duty cycle of the control valve was at its limit. Could my power box (PSI, unregulated) be causing this?

'In any case, I can't explain the feeling of weakness at low RPMs with these measurements. However, the air mass values are also in the lower range of the specified limits (a new mass airflow sensor was installed at the beginning of the year).'

Which other blocks should you, in my opinion, also log, which could cause the same effect? Fuel injection amount, fuel injection timing


hoping for advice,

Hello Jens,
No advice, just merged your double post into a single one.

Best regards, Rudi.

Hello Jens,

Is there anything stored in the error memory?

The boost pressure and air mass readings actually look good.
The duty cycle of the solenoid valve used for turbocharger boost pressure control is actually at its maximum limit.
Since the pressure adjustment is working well and the control unit is not going into emergency mode, I wouldn't adjust the VTG (Variable Turbine Geometry) setting.
A high duty cycle on the boost pressure solenoid valve might be coming from the control unit.

Have you checked the EGR valve for leaks, as well as the entire turbocharger system for leaks?

You can also record the amount of fuel injected versus engine speed during full throttle. This should be approximately the same once sufficient boost pressure has been achieved.
If it is significantly lower in your engine's low RPM range, the cause of the fuel quantity reduction in the engine control unit must be investigated.
Up to what RPM is your "weak" range?

Best regards, Rainer.

Hello Jens,

Is there nothing in the error memory?

... yes, and specifically...

01268 - Quantity Adjuster (N146)
35-10 - - - Intermittent

...but it's clear that this happens when you quickly turn the ignition off and then on. In that case, the power box hasn't yet shut off when the ignition is turned on, and the engine control unit detects the '10-cent trick.'

And then there was also...

00575 - Shareware version. To decode all diagnostic trouble codes (DTCs).
17:00 - Please register/activate.

(according to the error database, intake manifold pressure/control difference), this sometimes happens in cold weather and after a long stretch of full throttle on the track. I now also know why .



Have you checked the EGR valve for leaks, as well as the entire turbocharger pressure system?

... there was a slight oil film on the underside of the hose, where the EGR valve is located. However, I couldn't hear any hissing sounds with the engine running up to 3000 RPM. So, it should be okay, right?

What you can still record is the amount of fuel injected over the engine speed during full throttle. This should be approximately the same once sufficient boost pressure has been built up.
If it is significantly lower in your engine's 'weak' RPM range, the cause of the fuel quantity reduction in the engine control unit must be investigated.

... I will do that tomorrow. Which ad group is it in?
actual injection volume?

Up to what RPM is your 'weak' range?


... up to approximately 2200 RPM.

jenseden wrote:

... there was a slight oil film on the underside of the hose, where the EGR valve is located. However, I couldn't hear any hissing while the engine was running, up to 3000 RPM. So, it should be okay, right?

Hi Jens,

Oil on the charge air pipe usually indicates leaks.
Even at 3000 rpm, almost no boost pressure is built up while the engine is idling, so you can barely hear any whistling sound.

Quote:

Which ad group does this belong to? actual injection amount?

I'll send you a label file from AFN.

Check also the measurement group related to the start of injection. If it's too late, it can also cause the engine to lose power .

Hello,

Okay, here are the diagrams for the injection amount and the start of injection.
It actually looks pretty good, right?

Injection volume:
http://www.informatik-consulting.de/kunden/VAG-COM/Spritzmenge-30-11-02.gif

Injection start:
http://www.informatik-consulting.de/kunden/VAG-COM/Spritzbeginn-30-11-02.gif

Sure, here is the translation of the text from German to English:

'Notes?'

I also changed the air filter today, even though it was supposedly still good according to the friendly service (inspection in the summer). I also removed a stray oak leaf from the airbox. There were several dead flies and bird feathers in the old air filter, so I wonder if the friendly service even opened the airbox.

During the subsequent test drive, the air mass in the lower RPM range was also approximately 80 mg/H higher, and the car pulled slightly better. Look at that.