Hard starting 1991 300CE (M104)

[rgnprof]

I have had ongoing running problems with this car and it is still running rich and getting poor mileage - I have posted before with little success in figuring out the problem.

Lately, the car is now hard to start - sometimes it takes 10 seconds of cranking, 2 or 3 times on first, cold start before it will finally fire up. Hot starts are OK...

It 'feels' like a fuel problem, but the fuel pumps do run when key is turned on. Problem is worse in colder weather, but once it starts, the car runs fine - no stalling, accelerates great - as stated above, still runs rich and I don't think the car is running in closed loop. My O2 sensor is a year old, but checking the voltage here indicates no fluctuation and my duty cycle drops to 3-5% and doesn't fluctuate much at all either.

I don't know if these problems are related or not...right now I'm just trying to figure out the hard starting/long cranking problem.

Any thoughts?

Thanks, ryan