2.0 TFSI engine misfires intermittently

Quote:

It is a Skoda Octavia RS TSI, manufactured in March 2013, model 1Z5. Address Motor Electronics (CCZ) Label file (not applicable) Part number SW 1Z0 *** 115 AF (original part likely 1Z0 XXX 115 AF). HW 1Z0 907 115F Component 2.0l R4/4V TFSI A020. Currently, I'm experiencing problems with

jerky acceleration.

Sure, here's the translation:

"Previous tips:"

Ich_Can_nix wrote:

Hello gtone, The correct SW number for your control unit is: 1Z0 907 115 AF. I can't help you with the correct label file, but perhaps I can help you solve the problem with your sputtering engine. The CCZA engine is known for being a rough-running engine - WITHOUT ERROR CODE ENTRIES. The engines were equipped with faulty sensor elements in the mass airflow sensor between week 25 of 2012 and week 10 of 2013. Disconnect the mass airflow sensor and drive. Is the jerking gone? Can you replace the mass airflow sensor (MAF sensor)? Is the stuttering still present, or is it not the mass airflow sensor? The error can also be caused by improperly fitted, low-quality, or dirty air filters. After that, the usual suspects for air leaks in the charge air system remain as potential sources of error. Best regards, Michael

Ich_Can_nix wrote:

Good morning, Did you install an OEM replacement part? If it's an accessory, you may have inadvertently made the problem worse. Then, the LMM cannot yet be ruled out as a potential source of error. Just unplug it and drive without it! Furthermore, you can then check if your engine control unit has stored any error codes. If the engine has been cleaned frequently, both the connectors of the ignition coils and the contact surfaces of the spark plugs could be the cause of the problem. It is also possible to create jolting or jerking movements, even without generating an error message in the system's memory, by introducing a small amount of resistance. Best regards, Michael

Misfire? There might be counters for each individual cylinder.

Then, a common problem with tuned TFSI engines is often the fuel pump's fuel delivery capacity. The impeller might be clogged, or the pump piston might be defective.

If the problem is the amount of fuel being delivered, you would see regulation issues (setpoint vs. actual) in the fuel pressure.

In which driving conditions does the vehicle jerk?

Found:
https://www.bar-tek.com/de/tfsi-upgrade-niederdruck-kraftstoffpumpe-v3-bar-tek

The text is interesting because it discusses behavior during cornering.
What kind of engine/power output do you have?

Is the engine noise normal compared to other vehicles with the same engine?

Best regards, Rainer.

If I may, I'll post a log file tomorrow.
Interestingly, it vibrates amusingly in the 3rd and 4th gears at approximately 2,500-3,500 RPM. It doesn't always happen, and it's more likely to occur with slower acceleration.
I also suspect the fuel pump. The idle speed drops to 80% - possibly indicating a problem?
I usually only drive cars with around 250 horsepower.

The high-pressure pump can reach up to 160 bar, but then it is regulated back down.
What's new is that the fuel line vibrates along with the engine speed.

Attached is a file from yesterday, but there was no buffering this time.

Please create a log file containing the following data: fuel pressure (target/actual/duty cycle), engine speed, and air mass.

If possible ("Marker" in VCDS), mark the locations where the jerking occurs.

Have you tried Michael's suggestion of driving with the MAF sensor connector disconnected? I don't see anything; maybe I also missed it...

Best regards, Rainer.

Good morning.

Now I was able to log the error for the first time and multiple times.
What I've noticed is the deviation between the actual and target rail pressure.
But even the open fuel tank vent, should it be fully open at that moment?

I noticed that the AH might have installed the wrong part.
The HD pump was replaced last year.

dieselschrauber wrote:

Create a log file with fuel pressure (setpoint/actual/duty cycle), engine speed, and air mass. If possible ("Marker" in VCDS), mark the locations where the jerking occurs. Have you tried Michael's suggestion of driving with the MAF sensor connector disconnected? I don't see anything; maybe I also missed it... Best regards, Rainer

Good morning.

The more different values that are logged, the lower the sampling rate becomes. Therefore, choose appropriate values and, if the control unit offers a "turbo mode," utilize it.

Fuel vent: For a test drive, simply don't fully tighten the fuel tank cap, allowing you to rule out any issues related to the fuel vent.

How does the car drive with the MAF sensor disconnected?

Best regards, Rainer.

I'll log it again in the next few days.
I tested the tank without making any changes.

Unfortunately, I can't test the LMM right now because the hoist cable has broken.

I was just able to log in again.
I'm not a professional, but based on this data, I suspect there might be a problem with the HDPump.

Hello,

I took a look at the marked sections in the log.
After the markings, the engine speed and air mass decrease; I assume you simply released the accelerator pedal?

At the marked points, it is noticeable that the fuel pressure cannot be regulated and oscillates around the target value (relatively strongly), as shown in the image from KDataScope.

Let me see if I can find anything about fuel pressure regulation; I don't have a motor like that in my possession.

Best regards, Rainer.

There is a

Quote:

Fuel Pressure Regulator Valve N276

.

The number on your engine might be different.

If it's difficult to operate, you'll experience the exact effect with the fuel pressure.

In the pictures online, it's directly attached to the high-pressure pump/piston.

Thank you very much for the analysis.

The waste is likely caused by switching operations or gas leakage, as you correctly suspected.
Could you explain what might be causing this stuttering when I accelerate?

After the problem typically only occurs in the 3rd and 4th... If the problem occurs in a specific aisle, I could re-log the values for that smaller aisle.

Yes, stuttering can be caused by that. Since the valve is relatively inexpensive, I would just replace it.

I'll try it out.
My mechanic friend just asked if it could also be caused by the low-pressure fuel pump.
I don't see any readings labeled "low pressure" in the data, or have I already found the correct one for the high-pressure system by chance?

Hello.

Quote:

My mechanic friend just asked if it could also be caused by the low-pressure fuel pump.

No idea. But if the power is consistently available when you're running at full throttle, then you don't have a problem with insufficient fuel supply.

Quote:

Fuel Metering Valve N290

It could also be a source of evil and probably contains splinters from time to time.

Isn't the low-pressure system simply a pump?
Do you have a suitable SSP (Service Service Program) for my engine type?

Best regards, Rainer.

Exactly, and his concern would be that the (in-tank) pump might lose power, which could potentially prevent the high-pressure pump from receiving enough fuel.

Okay, I think we should start with the valve or the HD pump, as that seems like the most logical place to begin.

Could the clock rate of the (in-tank) pump provide insights? For example, if it were at 100%, would that suggest an insufficient supply to the high-pressure pump?

I don't have a workshop manual, but it would be a good time to get one .

I don't think my Octavia has the N290.

Here's a log with a new HD pump .
It was probably the pump, but I'm not ready to announce it yet.