Air fuel and o2 sensor problem
 

Hey all,

so my case is a little weird as I have been trying to fix this for the last 2 months.

So to start with, I have a 2005 DE roadster with 75000 km (I live in Morocco).
the day I bought the car, everything was fine. When I parked it overnight, my little chihuahua chew on the downstream o2 sensor cables (green and blue plugs).
of course, the next day ---> Check engine light, performance and mileage went down to the crapper.
I did a lot of research on the forum and discovered that it wasn't a problem if I get it fixed quickly after, otherwise it was going to affect the cats.
I ordered a OEM o2 sensor (the driver side only because the other one was still fine)
while I was waiting for the sensor to come, my dog chew on the other one and damaged it.
when I received the o2 sensor, I went to a guy that had Nissan engines sitting and tried to find a de engine with the same sensor. of course, didn't find one. However he had a Tiida engine with the same sensor green plug, except the head is different: on the DE it's a long nose and on the tiida it is shorter and flatter but it fits on both the plug and the cat's side, I figured they do the same job (the internet thinks the same apparently, if it fits, it sits).
before mounting them, I did a diagnostic and found bank 1 and 2 o2 sensors threw codes which I was prepared to see.
I plugged them and deleted the codes. it was fine until I came back home: turned off the engine and started it again, and of course: check engine light came back on.
Went back to the mechanic and found out the tiida o2 sensor didn't sit properly on the plug's side but still the same connector. so I shaved off a bit on the side like shown on the picture, and the connector went all the way inside the plug, like it is supposed to sit (that's today).
did the diagnostic and all four o2 sensors (upstream and downstream) showed up on the tool. erased them, came back home, turned off the car and back on ---> CEL again.

I don't know what to do next, I am thinking of ordering decats and tweak the ECU so it doesn't show the CEL but I like to keep my cars stock and I already spent to much time money and energy into fixing this and I am sure it's not going to fix the performance and mileage issue, I really want to get to the bottom of this.

thanks in advance.

CEL for what? o2 heater, lean, rich?
Any exhaust leaks? Bad Cat?

If it's a cel for the cat then get an o2 sensor extender(make sure it will fit, they sell them in 90degree options also) and it SHOULD fix it.

Hey, I don't remember the exact code but I remember it displaying all sensors HEATER.
do you think the extension should fix this ?

What I have done in a number of my vehicles is to order the generic or lowest-cost version of the O2 sensor, and then solder the connections to the harness from the original O2 sensor.

So, for example, if you have a 3-wire Bosch O2 sensor - you buy the lowest-cost version of that Bosch 3-wire O2 sensor you can find (in my case, it was usually a version for a Ford). Then I would move the original connector/wires over to the new O2 sensor and run that.

The cost seemed to be more in keeping a different version of connector or cable for a specific application, not so much in the sensor itself. The costs for O2 sensors came down as more options appeared for where to purchase them as the internet matured. Also, I haven't had an O2-sensor code in a long time on any of my vehicles - the sensors either got much better (longer-life), or the ECU SW doesn't seem to care as much.

Heater is either a wiring issue or bad heater element in the sensor. An o2 sensor extender will not fix this issue.

Thanks for your answers. The issue is it throws a code for all sensors in bank 1 and 2, heater related.
can it be only one or is it all of them that got fried?

Up ?

Hello guys,
i have good and bad news.
i checked the fuse box earlier to find that the o2 sensor fuse was blown. So i changed it, reset the ECU and went out for a 30 minutes drive. The CEL didnt come back (good news) but the mileage stayed the same(bad news) even after resetting the gauge. I also see a slight difference in performance but nothing major
is this a sign that everything is good?
i will go do a diagnostic tomorrow to make sure.