Ok so here is my problem. I recently bought a new after market exhaust. Headers back. The new exhaust had the O2 sensor in the down pipe not in the manifold. So Ive just had it disconnected until yesterday. I extended the wires and plugged in the O2 sensor. I reset the ECU, started the car fine backed it out of the garage no problems. Well I took it for a test ride around the block and while driving I lose all power. Seems like it is misfiring. The car idles fine but when driving just about goes no where. So I pull over unplug the O2 sensor drives fine again. Idles fine and has power while driving with the O2 sensor unplugged. Before I changed the exhaust the O2 sensor was plugged in and working fine. Do I have a bad O2 sensor now ? Could I have connected the wires wrong ? When the O2 sensor was plugged in there was no CEL. But of course once I unplugged it the CEL came on. Any ideas would be much appreciated. Thanks in advance.

90 accord 2dr lx
5 spd mt
4 cyl
180k

 

How careful were you with the wires? These are tiny voltages being sent utmost care should be used stripping insulation to not damage any strands of the wire and soldered/heatwrapped.I would think something is wired wrong but unplugging the O2 and assuming that that component is the culprit is not 100 percent surefire the engine goes into closed circuit mode any time any component fuel/air related is unplugged and will revert to a Generic Fuel/air mix that will let the vehicle run though not optimallly it could be coincidence and you could be suffering from clogged EGR ports known issue with 90-93 accord that causes stumbling on acceleration from EGR gasses going down only one cylynder causing misfire.

 

I was careful stripping the wires making sure not to fray any of them. I soldered both connections, heat wrapped the connections then wrapped them in electrical tape. Then I wrapped the whole wiring assembly from o2 sensor to the connection at the front of the motor in electrical tape and wire tied it out of the way of any moving parts. I didnt think of the EGR valve Ill have to check that. Is there anything on this website about cleaning it ? Maybe Ill unplug the EGR valve and plug the o2 sensor in. The only odd thing is it ran fine (well as fine as a car with 180k can run) before the after market exhaust. Thanks for the reply.

 

I found something on the net explaining how to clean them. Do you think its just coincidental that when I re-wired the o2 sensor it started acting up when it wasnt before ?

 

could be just a coincidence, but i think the o2 sensor would throw a CEL if it was wired wrong or something.. right?

 

true. Thanks everyone for the feed back. Ill try the EGR port cleaning maybe this weekend and report back.