I purchased my 94 pile minus motor, incidentally, it was missing the whole exhaust system, it runs now, runs pretty smooth, i have all new vacuum lines and sensors, it was a used engine, around 130,000, so after i got it running, i prob changed the oil and filter 2-3 times, (just to be safe/ghetto flush) within a two week period (it hasnt made it out of the garage yet/suspension/brake work ) the problem im having, the check engine light is on,i dont have a scanner, but was wondering if not having a catalytic converter and 1 02 sensor (in the downtube) would be the culprit? How many 02's are there? Also, if im supposed to have 2 02 sensors, where do i find the wiring for it???? Again, its a 1994 xj/ with a 94 engine, not the orig. Thanks in advance

 

The O2 sensor just after the manifold will throw a code but the one in the catalytic converter wont. I dont have one there.
You can the codes with the check engine light on them, I cant remember how but Ive done it a couple of times following the workkshop manual

 

ok, thanks man!

 

Wires come from harness (top of intake by steering pump) & go straight down to one & only o2 sensor. Turn key on,off,on,off,on & engine light will flash code.