I rescued my 1989 Volvo 240 automatic from previous owners who did not take such good care of it. For the past few months I have been nursing it back to health.
Things I have done so far.
Cleaned the heck out of it. Cleaned oil trap, replaced oil trap o-ring, replaced intake and throttle body gaskets, cleaned throttle body and air control valve, good tune up, replaced rack and pinion and tie rod ends, replaced crank sensor and recently replaced camshaft, timing belt, front seals, aseccories belts and water pump.
With all of this my idle has gotten better but is still kinda rough, kinda high and sometimes stalls at stop lights. So I figured I would replace the O2 sensor. Much to my surprise I have no O2 sensor. I knew that I did not have a catalytic converter (was planning to get one). So I have no O2 sensor anywhere. Not on my exhaust manifold, header pipe, or anything. I think the cheapest route would be to have an O2 bung welded to my header pipe install an O2 sensor and figure out where the end of the O2 wires plug up to. Or I could buy a new header pipe from FCP Groton ($100.) which has a hole for the O2 sensor. I can not believe that my car was running half way decent. Now I need to figure out where are my old o2 sensor wires were so I can plug in a new one.
Any help here would be greatly appreciated.
Thanks
pics below

<img src="http://i169.photobucket.com/albums/u...g?t=1199146458">

<img src="http://i169.photobucket.com/albums/u...g?t=1199146526

 

well, on the 89 740, the O2 sensor is plummed in just before the Cat, actually on the Cat if I remember right.

 

The wires are up almost by the hood hinge on the passenger side.