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duxthe1 · #3 09-14-2019, 09:30 AM

Been there, done that. I've got MS2-E on my turbo'd wagon and I love it. If you're gonna boost any of these engines, its absolutely the way to go. On my '90 300 CE I've decided to keep it naturally aspirated so the CIS, in theory, is completely capable of meeting its fueling demands. If, big if, I pull this off, it can positively impact the whole of the classic MB community.

This type of hacking, has 3 stages. Stage 1 is finding a better performing module and simply copying its program. This alone has good potential for me since my monitoring has shown that my California version has no WOT enrichment. It stays in closed loop with the full load contact closed all the way to redline. No Bueno. The hard part is actually sourcing better performing ECUs. If you look around online you'll find that old skool Porsce and VW guys with CIS already got this much figured out for their platforms.

Stage 2 is modifying existing programming. This is where I'd like to get to. It is also monumentally difficult for someone not from a programming background. Not impossible, but very, very difficult. The upside to pulling this off is equally rewarding. Aside from altering fueling, the potential exists to change the data communicated with the EZL, turn off things like EGR, and alter the idle speed. Everyone knows these engines tend to overheat, and at hot low idle speed it doesn't matter how much air you move though the radiator, the water pump isn't moving enough coolant to keep the temps down. I'd love to bump the hot engine idle speed target up about 150-200 RPM.

Stage 3 is writing my own new code. Of the approx. 20 kilo bytes in the existing program, at least 1/2 to 3/4 has to be bloat. An early black box ROM dump is only 5KB in size and even that could be whittled down since the CIS only has to do a few things. Control idle speed, control EHA, serial communicate with the EZL. Cold start injector would be nice as well as evap solenoid control but not absolutely necessary. This scratch built code of course would *ahem* be only for off road use. This is likely easier than stage 2 since it really only involves learning how to code for the 80535, and not also deciphering a bunch of code targeted at the 80535. Down side of course is not having the development Bosch / MB put into this module to begin with.