Problem with oxygen sensor or other sensor ..?

J-Rdiaz wrote: In oxygen sensor it must be in the admission multiple possibly covered for that you do not find it, remember that the black smoke is only fuel then you drown, if it can be a covered injector or such see you have to regulate the butterfly, it is best to remember that it moved or change to the car to be with those symptoms

I correct you so that it does not miscarriage.
The oxygen or Lambda sensor has the function of controlling the oxygen content in combustion gases in the exhaust, therefore it could never be in the admission.

Francorv51 wrote: I will try everything that they have recommended and I tell you how it went, I still can't locate the oxygen sensor, I get the impression that this model of the vehicle does not use it. Thanks for your answers

In those years, the installation of Lambda probes for manufacturers and some vehicles did not have it as in your case, it was not strictly mandatory.
Look for some air sucking by the admission or very high fuel PRSION because of the defective regulator (pressure running 2.5/2.7 bars) that is surely there the problem.

It is also good for you to check the engine coolant temperature sensor or coolant sensor

It is located in the escape multiple. (Not in the admission)
it usually has a black wire

E. Rocca wrote: It is located in the escape multiple. (Not in the admission)
it usually has a black wire

Correct, the black cable is the output signal.