Poor cold start, misfires, high diesel consumption - Passat

Hello,
My brother is having a problem with his Passat 2.0 TDI 140 hp: it starts very poorly when cold. The engine runs very rough, the average fuel consumption is about 12 liters per 100 km, and it's 2 liters at idle. There are no error codes stored in the system. According to the diagnostic readings, the idle speed is constantly around 825 rpm (despite the significant roughness).
What values should I read out here? (Ideally with target/reference values).

(AGR is controlled according to VCDS specifications, the ZMS has been replaced.)

I urgently need help.

Hi,

Mileage? Engine code letter? 2-valve or 4-valve cylinder head?

Are you familiar with the problem of the PD elements in the 2V cylinder head?

Best regards, Rainer.

Once it's warmed up, does it run smoothly and produce normal power?

Compression okay?

Hello Rainer,

Thank you for the quick response. If I understand correctly, it's the BMM engine. Unfortunately, the vehicle is located 100 km away. I can't say right now whether it's a cylinder head issue (when haven't there been PDE problems ).

"Hey rüdi, it starts much better when it's warm. Is there a way to test the compression other than using a VCDS?"

"If the engine starts correctly and runs well when warm, it might be worth installing check valves in the fuel lines (both supply and return). If the cold start problems then disappear or improve, it's likely that the issue is caused by leaking injectors."

pierre87 wrote:

(When have there ever been no PDE problems

?
I have not experienced any problems with the 4-valve cylinder heads equipped with pressure divider units and solenoid valves.

Quote:

I have not experienced any problems with the 4-valve cylinder heads equipped with PD units and solenoid valves.

Are you referring to the processing method that uses PPDs and results in a much smoother finish on the surface?

Bei der alten Magnetventilausführung sind mir beim 16V einige Fälle bekannt, die Wurfpassungen hatten. (s. VPlease provide the text you would like me to translate from German to English. I need the text to be able to complete your request.

Okay, I understand. Please provide the German text you want me to translate into English. I will only provide the translation.

Quote:

Are you referring to the implementation using PPDs, which are processed much more smoothly from the surface?

No, actually not exactly those ones.
PPDs may sometimes tend to carbonize, but generally, attaching 4-valve PPDs is more effective than attaching 2-valve ones (only on one side).

Best regards, Rainer.