Rough idle for first 4-5 minutes on start up cold and hot - PeachParts Mercedes-Benz Forum

lsmalley · #1 10-07-2023, 01:38 PM

So whatever I did ended up greatly compromising fuel economy.....I'm talking maybe 12 to 13 mpg highway. Needle was at halfway mark when I left home with 146 miles, now it's between the R and the last bar at 182 miles. Blue smoke at idle with engine idle surging up and down between 500 and 1000 rpm

Sugar Bear · #2 10-07-2023, 02:15 PM

Hmm.... probably best to retrace everything you've done so far. Could you split the difference of the adjustment made to the height of the plate?

Do the spark plugs have buildup on one side of the insulator? Rough cold idle, blue smoke and if it's there buildup on one side of the insulator can be valve seals. They're relatively easy to replace, based upon what you've done so far you can reply them.

Dave Kost · #3 10-07-2023, 03:23 PM

Quote:

Originally Posted by lsmalley

So whatever I did ended up greatly compromising fuel economy.....I'm talking maybe 12 to 13 mpg highway. Needle was at halfway mark when I left home with 146 miles, now it's between the R and the last bar at 182 miles. Blue smoke at idle with engine idle surging up and down between 500 and 1000 rpm

After you reset the AFM plate height, how did you recalibrate the mixture? If you unplug the OVP does idle still surge?

I noticed that you have a 3.0 in your 190e. Did you swap out the ECU, AFM, FD too?

I like the way Steve Brotherton sets the initial mixture. With the EHA unplugged , you read the voltage of the signal wire of the O2 sensor @80C. You want to see the voltage oscillating around .45vdc. This is the range that the ECU -EHA can react and achieve lambda. You then of course, plug the EHA back in.