W123 M110 280E Mixture Adjustment?
 

I've got a 79 280E that seems like it's running rich. I was wondering what the proper procedure is to adjust the A/F mixture. Where do you adjust it at? Is there a good way to guestimate A/F mixture without a CO2 meter? Checking the spark plugs?

Thanks for the help!!

Dan,
a good starting point is to richen or lean the engine for the highest vacuum reading & then lean the engine slightly. Then set the parking brake & reset that mixture in gear for a high vacuum reading then lean out just a bit!

OF course on that car the valves must be adjusted properly & timing set before adjusting the mixture!

Thanks, MB Doc!

Where do you adjust the mixture on this CIS system?
What should the timing be set at?

The mixture adjustment is between the fuel distributor & the air flow plate just like the 16V. However you must remove a screw to access the 3MM allen that adjusts the mixture! AS you change the mixture you must cover that access hole with a "finger"(or re-install the screw) to block off a vacuum leak!

Timing for a USA car should be TDC(with vacuum) at idle & at 3500RPM between 32-35deg.

MB Doc is this procedure and timing settings the same for a 1981 280E?