It's about a w124 sedan,1990,M102.963,WDB1240211B384210

The car starts very hard.
Once warmed up a bit 40'ish celsius it runs great.
I noticed a red/green wire(with the connector cut off) rigged to a brown wire that belongs to a 2 pin connector,that belongs to a 3 pin sensor on the head.
If i remove the red/green wire the car starts great but it seems to run very bad ,like it runs on 3 cylinders and white smoke comes out the exhaust.

This is the red/green wire i'm talking about.





And the sensor wire that the red/green one is rigged to.



The internet knows nothing about this wire,where it comes from,where it should be and so on