View Single Post
Old 10-13-2012, 08:59 AM   #110
roger 04 rt OP
Beastly Adventurer
roger 04 rt's Avatar
Joined: Nov 2011
Location: Massachusetts
Oddometer: 2,268
Before posting the next few diagrams, I spotted a function that I'd originally left off the Motronic diagram that is relevant to any fueling modifications that disable the Motronic's Closed Loop operation (1150 Motronic MA 2.4). If you look back at the previous two charts, they have a "Limp" function in the final fueling decision box.

The Limp box is the final step in Open Loop fueling, just after Adapt values have been applied. The Limp function as I have measured it (plot below) expands the variation of Open Loop fueling to a 10% variation. That is twice the amount of mixture variation that occurs in Closed Loop. The full post was here, Open Loop fueling variation. Although there is speculation that the Limp-Home function uses is a rich mixture, the measurements say that it runs 5% richer than and 5% leaner than the fuel table cruising target of 14.7:1.

What that means on an 1150 is that if you disconnect the O2 sensor and run a Powercommander, Techlusion, 3.5 Bar pressure regulator or BoosterPlug as an Open Loop fueling enhancement you can count on the Motronic to vary the fueling in a 10% range, like the plot below.

The next post will be a block diagram of the Wideband O2 system.

roger 04 rt is offline   Reply With Quote