lambda system freeking out in a 930
 

hi fellows Pelicans.
lambda system is freaking out in my 86 930. it is a US version - 930/68, with lambda circuit controlling mixture/emission.

car runs great without lambda sensor connected. once it is hooked up, however, AFR goes down to ~10 or even below.

once sensor is disconnected, it goes back to whatever is set using mixture screw.
below two videos showing how it behaves.

https://youtu.be/dVhl5wPgZIg
https://youtu.be/yJJd4x7ESO8

lambda sensor has already been replaced with new unit.

anyone any ideas?

thanks!
Krzysztof

do you mean the O2 sensor was replaced?

check speed relay, perhaps bad solder joint. one side it for the fuel pump the other for the O2 sensor
throttle position switch

hi folks,
thought i'd come back to this thread to report on the solution.
appeared that it was a bad ground. ended up adding addn'l grounding wire to the o2 sensor brain unit and all is back to the order now.

thanks for suggestions!
Krzysztof