My R129 '93 has no O2 sensors and no Cat and therefore I wonder how the self adaption works. How can the car adapt to air leaks etc over it's life if it cannot measure them - or can it somehow?

No O2 sensors threw me for a while because by using a scanner I can see O2 real time data from the LH module, but I suspect that this figure is mapped - is this correct? Does the LH module 'inject' the signal fooling the LH software into thinking it's got O2 sensors?

Back to self adaption.....if the car cannot sense the actual real air/fuel ratio at the exhaust manifold, how can it learn? Perhaps this signal is also mapped against time?

I'm pondering this as I believe my car is running weak CO = 0.15 (remember no Cat) and she suffers from a little surging when really cold - which can be made worse when I pull a pipe to inject more air.

Any thoughts?

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'93 R129 500SL-32
'89 190E 2.6 - sold in 2002

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