Subject: 745, 735 e23 Motronic techie question.... Author: johnhstein as johnhstein, 85-M6CSi, 85 745i (moderator) : member since July, 2004 : 693 posts Posted on: 2011-09-22 12:36:46

Been pondering this for some time..

Are the Motronic inputs from a US SPec e23/735 and the Euro spec e23/745 the arranged the same EXCEPT (of course) for the O2 sensor lead on the US Spec?

If so, then why can't you mount the US Spec Motronic on the 745 and add the O2 sensor?

Ok, here is my logic... .. Wnen not on boost, it would run like the normal 735 with the O2 sensor managing the fuel mixture to near stoich, but when you go 'on-boost', it would go lean due to the input from the O2 sensor... So...

You put in an 'over atmospheric' switch to eliminate the O2 input, sending the Motronic into the 'open loop' status and allowing the fuel pressure regulator to bring the fuel mixtures up to the factory preset 'on-boost' levels... Some how it seems like such a simple solution...

(BTW... still making progress on getting the 745 back on the road... had to order a bunch of new parts ....)

Regards

John Stein, ATP, Retired Flight Test Pilot

Gulf Coast Beach Cams

• 745, 735 e23 Motronic techie question.... - johnhstein, 85-M6CSi, 85 745i 2011-09-22 12:36:46 (1111 views)
  • Re: 745, 735 e23 Motronic techie question.... - bodoke 2011-09-27 22:38:02 (1053 views)
  • Re: 745, 735 e23 Motronic techie question.... - demet 2011-09-22 18:37:24 (1058 views)
  • Re: 745, 735 e23 Motronic techie question.... - Hitmanx 2011-09-22 17:55:17 (1087 views)