Power loss, Golf 5 BLX

Hello everyone,

Maybe you have another idea.

Vehicle:
Golf 5 BLX Engine Control Unit (ECU) 06F 906 056 DE.

Error log entry: (See attachment)

Problem: Mostly, when the engine is in the warm-up phase and under heavy load (e.g., driving uphill), there is no throttle response or a lack of power. It then only revs up to 3000 RPM (limp mode) or doesn't respond to the accelerator at all.

Knock sensors have already been checked, but the problem still persists.

- Compression I/O.

- Pressure loss test: OK.

-Fuel injectors sealing properly while stationary (rail pressure increase with the engine off).

The readiness code has been generated and is in order.

-High pressure at full load when the engine is running well: 110 bar. When it shuts off, it drops to approximately 60 bar.

-Low pressure: 5.1 bar (when operating correctly, this value remains consistent even if a complaint is filed).

-The Lambda controller has been running at -7% for an extended period.

-While idling, approximately 3 instances of misfire were detected within 2 minutes. No misfires were detectable during driving.

Sure, here's the translation:

"Parts that have been replaced:"

Low-pressure pump, high-pressure pump, with lifter (camshaft not engaged), low-pressure sensor for fuel pressure, and high-pressure sensor.

The software is up to date.

Hello,

Nice pictures, but where can you see the measurement display, and what does it represent?

Since VCScope is rather useless in this case, why not simply upload the log file? Can you then use KDataScope to view the data, and that will allow you to see what's there?

Best regards, Rainer.

Possibly, there might be damage to the wiring harness. Have you checked that already? Perhaps. Weasel damage?

The decreasing pressure could also be explained by the emergency procedures.

Hello everyone.

The wiring harness has been inspected.
I don't think it's a complete engine failure, because no spark plug replacement is necessary for it to run properly again.

In the log, point 1 states: "The vehicle shook briefly, then the high pressure dropped."
Point 2: Pressure - apply full throttle for 5 seconds, maintaining a constant engine speed of 3000 RPM.

The accelerator pedal was always fully depressed, and the power returns on its own.

Hi Dani,

Does anyone have any ideas? Or experiences? Best regards.

Idea, yes... No experience.

16575 - Fuel pressure sensor (G247)
P0191 - 008 - Implausible signal - Intermittent.

You have already replaced this sensor, but it didn't resolve the issue.

The wiring harness has already been mentioned.

If nothing else works, you would need to check the plausibility of the sensor readings/data during operation (using a pressure gauge) to determine whether the sensor reading or the actual pressure is incorrect.

I'm contacting you again regarding the fuel pressure error message.

I understand that the high pressure is dropping. In the measurement block, I have read the control signal from the fuel pressure regulating valve. This happens when the engine starts to misfire or lacks power.
The control unit significantly reduces the control signals, which is why there is no longer any high pressure.

visible in the images above, recorded with a Vcds scope.
You can also see it in the log file.

Can anyone explain why the engine control unit (ECU) is setting a fault code, "fuel pressure implausible," when it is itself lowering the fuel pressure?

Does anyone happen to have a spare control unit for testing?

Best regards,

At the very end of the log file, at the marked point 1 or 2, you can see how the high pressure drops even though the engine is always running at full throttle, and then automatically returns to normal pressure.
Best regards,

Identical error messages on the 2.0 FSI AXW engine...
Solution: Fuel pump control module (located at the rear of the pump).
Replaced with a new part (1K0 906 093 H) - error resolved.