[pbanders]

OK, guys, some of you have seen my psycho web site with all that info on D-Jetronic. Why did I do it? Because I had the same idle problem that's described here and I wanted to fix it!!!

Note: the stuff below assumes your engine is in good mechanical condition (good compression, intake vacuum, and valves adjusted) and that your ignition is correct (right timing and dwell, plug gap, all parts in good condition and vacuum cells that don't leak, right part numbers, etc.).

On my car (YOURS MAY BE DIFFERENT), the cause of the problem was a rich idle mixture. I had thought (mistakenly, from my days of owning carbs) that you adjusted the idle mixture to attain a maximum rpm for a specific setting of the bleed screw - WRONG. Set the idle to the factory spec of about 2 to 2.5 % CO (that's for my 2.0L, it's different for other engines) when fully warmed up, and adjust the bleed screw with minimal electrical load (no lights, etc.) for 1000 rpm. That's it. Now I can turn on the lights, heater blower, fresh air blower, etc, and I only get about a 150 rpm drop. Not as good as my M3, which has an idle stablizer (damn thing stays stuck at 650 rpm no matter WHAT), but a sight better than dropping below 500 rpm and boggling along.

The way you can tell if you've gone too lean is to park near the top of a gentle, long grade, and start the car when cold. As you go down hill, lift off the throttle completely. If you get any sounds of popping (very easy to hear), you're too lean, go clockwise a click on the ECU knob and try again. BTW, believe it or not, this method is recommended by the Elfrink FI guide and it works.

Don't go randomly changing ANY FI component without having shown it to be faulty. Use my web page to diagnose the parts first before chucking them.

Brad Anders