Qualmender Motor nach Motor/Turbo Tausch | Posts 16+

larrs wrote:

The old, defective turbo is "bone dry" on the exhaust side and, idiomatically speaking, a "deer brown" color.

The turbo gets so hot during operation that everything around it evaporates. Therefore, not entirely surprising.

larrs wrote:

I have added the difference expressions above.

These measurements must be taken under load. The mass flow rate is too low when the system is at rest. Focus on the logarithmic function and accelerate from 1,500 to 4,000 rpm in the highest possible gear.

It's relatively simple: Select the relevant measurement blocks, press "Log" at the bottom. Choose a filename, move the mouse cursor over the "Start" button (but don't click yet). Then, start the process and click "Start" just before the acceleration begins. At the end, click "Stop." (Caution: high speed.) Let the passenger make the inputs.

You would then generate logs of this kind, ranging from 1500 to 4000 entries, from the differential pressure mass flow meter and upload them here. We may ask you to repeat the measurement later with different parameters.

Greetings.
Guste.

I personally recommend replacing the injector for cylinder 3. He's gone.

Fuel injection deviation, cylinder 3: 1.05mg/stroke.

Marco_Gorski wrote:

I personally recommend replacing the injector from cylinder 3. He's gone. Fuel injection quantity deviation, cylinder 3: 1.05mg/stroke

Hello,

Unfortunately, life isn't that simple.
Since the beginning (kilometer 0), cylinder 4 in my BRE has shown an injection quantity deviation of approximately .8 mg/hour. The vehicle now has 320,000 kilometers on the odometer.

Generally, values within the range of +/- 2.0 mg/H can be tolerated, with a deviation of 1.0 mg/H being a common and harmless occurrence.

This finding is not based solely on my own vehicles, but on countless customer vehicles that I have worked on over the years, right here under the laptop.

Quote:

@dieselschrauber: Where can I find the shift time correction deviations? I'm looking for them in the relevant documents. No measurements of anything similar.

I'm pretty sure they're there, but besides going through everything from top to bottom, I can't think of much else to do, because I can't recall the exact name right now.
Possibly, a reader knows what these things are called, because you can enter the search term in the corresponding VCDS window.

Quote:

Fuel high pressure actual value: 175600 hPa Fuel high pressure setpoint: 325700 hPa

Hmm, if such deviations also occur during "rumbling," I would rather suspect a problem with the fuel pressure regulation.

Best regards, Rainer.

Shift time correction: depending on the engine, this is also known as zero-quantity correction or rail pressure calibration point.
The MSG determines the control durations for the main and auxiliary injection phases during operation (thrust), specifically identifying the durations during which the engine does not respond. These values are then used as corrections and incorporated into the actual control of the individual ESDs (Electronic Spray Devices).
An outlier would be an indication of an ESD (Electrostatic Discharge) or compression problem in the respective cylinder.
hg
Herbert.