Chosen Solution
My 190 i6 is very hard to start when cold. Were is the sensor located that enriches the fuel mixture? It runs fine after warming up,.
The cold start valve is normally located on the intake manifold or somewhere close to that. It has a fuel line and an electrical connector, and looks alot like a fuel Injector. But they normally only operate below 0° from what I found. And only for 12 seconds. If it has problems running until warm i would also check the coolant temp sensor.
