Paul, the only way you can eliminate that box and have your car run right, is to remove the frequency valve and turn your CIS system back into K-Basic.

That brain, even with the oxygen sensor unplugged, runs the frequency valve at a default setting. Usually 60% If I remember correctly.

Without the frequency valve operating at this default setting, you'd have to adjust the mixture to compensate, and it would throw off the accuracy of the mixture throughout the range. In other words, it may be in spec at idle, but go lean at higher revs for example.

So either convert the whole system back to K-Basic, or leave it alone. BTW, have you verified that it is working? If you unplug the little aluminum ice-cube relay next to the brain, does it run worse? If it runs the same when unplugged, then it isn't operating. That's your original relay BTW. The new replacement relays are black plastic. I bet the date stamp on that relay is '79 ot '80.

I also have an 80 Weissach. I'm in the process of upgrading: turbo tie rods, ball joints ferodo pads, Bilstein Sports. I gotta do it all before the little woman finds out. Eek! Next is the leather interior. Who can replace/replicate the Doric Gray interior? I know it's irreplaceable but gimmee some feedback on this. Let's stay in touch you and I. Shoot me an e-mail to compare notes. I've also wondered about the box. Just ask in this forum and you'll learn more about the subject than you really need to know.................

My car is a euro 83 and I just double checked and I have no relay just the box. Factory harness is still intact and I followed it into the tunnel past the shift coupler. I loose it under the car where it comes out of the tunnel but I see no relays under car. Could it be in the engine compartment? My car no longer has an air pump or lambda sensor.

Every couple months I have to go to John Walkers to get the CO set. When set car runs awsome after a couple months it surges at idle and stalls when cold. Still runs great when warmed up. Just wondering if this could be related? Car has a new WUR and checks out fine when CO is correct. Passed emissions no problem with no smog and GHL headers and dual out muff.

Dude, you put your weed in there!!! (Sorry, old Saturday Night Live episode rerun in my head)....