Sorry, been away a few days here. So, Bosch makes an official tool to set those, but I haven't ever been able to find one outside of the dealers, not even a replica on eBay or anything. It really kind of pisses me off, I'd like to have one very much...

Anyhow, what I have done in the past and had work relatively well is to get a really good digital voltmeter with a fast sampling rate. There is a small round plug on the left fender near the EZL with a screw cover on it, open this and plug one lead to pin 9 and one to chassis ground. with the engine at no load idle and at full operating temp, watch your meter reading. It should roam back and forth from about -.070 to +.070 or close to that. You adjust it from the tower that's between the air intake horn and the fuel distributor, it's a 3mm allen way down in there, and it's spring loaded, so you need to press down in order to turn it and be careful letting it go so you don't lose your wrench down the intake. Adjust it just a little at a time, and blip the throttle between adjustments to even it out. Clockwise makes it richer, counter makes it leaner. You should end up with a smooth idle and instant response to revving it out.

Another, lower tech, way is to get a good but very light magnet (a pocket screwdriver works well) and put it on the throttle plate. Adjust until it runs very well and bogs down if you push down on or pull up on the magnet at all.

Both of these have worked for me in the past, though they aren't perfect, you can get the mixture set pretty close.

__________________
Alex
MB Star certified, now independent.
Owner/Operator FDMotorsport Mpls. MN
Mercedes and GM certified transmission rebuilder
We all need a little help sometimes...

1998 E320 4MATIC-- stolen by my sister
1989 300TE-- sold
1999 C230 Kompressor