I need to put an oxygen sensor in my 1985 4000s. It doesn't have one at the moment because a previous owner put in an aftermarket exhaust that does not have a fitting for it. So I need to know where the wire from the sensor connects. Thanks for helping.

 

if its been getting through the emissions why would you need to alter it thing is you probably have the early system and the ECU would need upgrading, I can only speak of the early 1980s in the UK as they didn't have the emissions system fitted so perhaps yours could be an import therefore it would be senseless to upgrade without great wasted expense, old saying is ( if its working ok don't try to fix it ) unless your having problems getting it through emissions??

 

I do not think that this car is an import. It has an OXS light on the dash cluster that is constantly on. Also, right before the catalytic converter the weld for the pipe was busted. This leads me to think that the car has been running rich and the catalytic converter got too hot from a constantly rich fuel mixture, melted and the pressure got too high. I have since replaced the catalytic converter. There are a few wires that are not connected in the engine compartment but none of them seem to be for the oxygen sensor that I can tell. If I had a good idea where the oxygen sensor wire should be I could look around there.