I think the 405's Motronic EFI system is much more dependent on its O2
sensor than
the 505 XN6's Bosch K. K is the Germany abreviation for "continuous
injection" AKA
CIS or continuous injection system. At heart Bosch K is a mechanical fuel
injection system
with an O2 sensor added on to improve emissions and fuel economy. Whereas the
Motronic injection's heart is a computer receiving inputs from a multitude
of sensors
and varying the length of time the injectors are open for.
The PMA manual describes how to disarm the O2 sensor system in the XN6 505s
but I've seen no such info on the 405s. Several members have written to
this list
describing how changing the O2 sensors on their 405s corrected "drivability
problems".
Bob Bruce