After doing a bit more reading, a Bosch theory book stated the the EHA drops approx. 1 mA per 1000ft in altitude for certain KE systems that have it. Fair enough, how come MB never mentions this in thier factory info?? Also, the test proceedure in the generic Bosch book require the altitude compensation be disconnected in the basic Lambda test. If this guy can mention it, why can't MB?
BTW psfred, the CIS plate senses volume of air, not the density, which is the crux of the problem, the plate DOESN'T sense air in a way that accurately determines how much O2 per a given volume. Density drops roughly 2% per 1000ft, in my case, 12% total, and a corresponding drop in O2. I agree that the Lambda can correct for many situations that would ultimately result in the O2 sensors detecting an increase/decrease in exaust gas ratios. But that is only within a relatively small range. I am guessing that altitude correction was one parameter that could, under some circumstances, fall out of the range that the Lambda is designed to correct for. Why put it in otherwise, unless there was some EPA nerd trying to ensure the emissions reliabilty under just about any circumstances? Comments?