Cold Start Problems AFN: Troubleshooting Guide

Hello.
Unfortunately, the reason for this issue still hasn't been identified. Here's the problem again.
When the outside temperature is above 0°C and the engine is cold, the car starts without any problems after a short preheating period.
The car always starts when the engine is warm.
When the engine is cold and the outside temperature is above 0°C (without preheating), the car only starts after a long cranking period (accompanied by a huge cloud of white smoke).
Okay, so it's the same problem at around 20°C outside temperature with a cold engine.
Engine compression is good (AT block replaced at 20,000 km), fuel injectors are new, the ESP (electronic stability program) is also new, glow plugs are okay. The temperature sensor is also okay. The fuel injection timing is also within the tolerance limits (according to the Audi diagram).
Okay, so, if I disconnect the plug from the temperature sensor (when the engine is cold) and then start the engine (with a little preheating), it will also start.

Does anyone have any ideas about what else I could do?
Yes, the car has a chip tuning from the company ********, but that's been there for a while, and I didn't have these problems before.
LMM knives should also be fine because they can reach their maximum speed on the Autobahn.

Thank you & best regards.
Peter.

Hi.

Check this out:

/viewtopic.php?p=576#576

Otherwise, a new starter motor and/or battery might help: if the engine is rotating too slowly, it could potentially cause starting problems even when the engine is warm.
When the temperature sensor is disconnected, the starting fuel quantity is increased, which is then sufficient even for the lower cranking speed.