Hey guys this is sort of a random thread but figured I’d ask/post anyway.
Just did a 3.4 swap on a 93 T100.
Runs great and all that but still have a bit of modifying to do, and one of those modifications include the exhaust.
Since the 3.4 has a passanger side exhaust drop I decided instead of messing with switching the cross over pipe and all that stuff to make my own crossover pipe that runs along the trans cross member. And since I have a pipe bender this was quite easy. It’s a pretty interesting looking pipe but it works well and this way I could keep the original front O2 sensor location. Might post some pics later on but we’ll see.
So since the 3.4 exhaust was cut off infront of the original 3.4 cat I had the front O2 sensor bung but obviously not the rear one I made a crossover pipe after the original front O2 sensor that crosses over to the driver side and then meets up with the 3.0 exhaust just before it’s original O2 sensor and cat. Now since the 3.0 never had a rear O2 sensor to monitor the cat performance I would have to make up something, but I figured I would try it out how it is right now just to see what happens. And lone behold I don’t get a check engine light or any codes related to cat performance. basically the 3.0 old O2 sensor became my new rear O2 sensor, however there is no cat in between those 2 sensors, only a pretty long piece of pipe. Then after the 2nd o2 sensor I have the cat and the rest of the original exhaust.
How is this possible? why hasn’t it thrown a code yet for cat performance? I ran it for like half an hour and even took it for a drive and never got any codes yet. This would indicate to me that you could remove the cat with no lights on.
On my scanner the readings for the front sensor are at around .2 Volts at idle and the rear sits at like .7V
Maybe someone can shine some light on this…
Im happy there is no check engine light because otherwise I would have to cut out the O2 sensor bung and move it behind the cat. and since the cat on the 3.0 t100 sits behind the tcase I also have to extend the wiring for that too which would suck.
Ill update this thread if the CEL does end up coming on after driving it for a longer period of time but for now it seems to not mind that there is no converter.