I found the CIS on VW & Volvoe easy to work on with a good pressure gauge and adapters. How ever I HATE the LJet on the 74 seires Volvos. I had one no one could fix after some "creative repairs" done to it just beofore it was given to a new exwife in a divorceI my fading memory from VWAG days is correct: Bosch D (manifold pressure control analogue electronic) and Bosch K (CIS mass airflow mechanical) are based on Bendix patents - but developed much further by Robert Bosch. K Jetronic IMHO would make a nice system for an airplane, but lack of support these days would be a serious problem due to the aging nature of a/c fleets. When GM (Rochester mechanical injection on '57 and later SBC) introduced FI, it was also on Bendix licensed to GM and a small handful of Chrysler products came to market at same time with actual Bendix electronic injection (IIRC, ONLY time they ever sold into the production automobile injection business). ALL of this stuff is legacy from having the Kraut's do FI right in WWII aircraft and catch-up engineering on this side of the ocean during and post war. So thank DB-601/605 boffins for what we have today. Just odd that they had to license it back from Bendix to move forward! (IF I remember that correctly).