Dee_333

My car runs absolutely fine when its cold, and you first start it up. After driving for ten to twenty minutes (anytime in between) it will begin running poorly (almost sounds like slightly missing, or getting too much fuel perhaps..) It will also throw a check engine light.... I jumped it and checked the code, it reads code 1 (oxygen sensor upstream) I'm totally lost now...this damn wiring nightmare has been a pain in my ***, and I'm kinda taxed.....I almost considered paying a guy I know to figure it out and fix it for me, but I've gotten this far on my own....screw that! I went from five codes to one intermittent one now!

I'm not really sure what to do about this last annnooooyying *** code I have. I was told that I could wire a 4 wire o2 sensor right off of my ecu, and I had the pinout diagram, and which wires needed to go where on the ecu wires. I ran the wires through the firewall and to the o2 sensor to make it plug n play....The only thing I can POSSIBLY think of is I mixed up the two wires for the heater circuit, and put them to the wrong places. Would this possibly cause a problem along these lines?....

edit: I almost forgot....So you know I'm not a dipshit and overlook the simpleton nonsense....This is a brand new 4 wire Nippon Denso o2 sensor I am trying to use, Not some piece of garbage bosch turd, or something like that......... and I wouldn't even have used a 4 wire o2 sensor, but my VX one was throwing a code for a bad heater circuit so I bypassed the harness via the ECU..........(Just shoot me in the face already please, and get it over with!!) lol

Former User

What ECU?

If you unplug the O2 sensor, does the problem go away?

Dee_333

I'm running a P28 ECU, I think it may be chipped because I don't know that there is a rev-limiter. I know this to be a good ECU without any issues or codes, because I was running it in my 93 Z6 swapped coupe...

Honestly, I don't think I have actually tried unplugging the o2 sensor while it is throwing the code, but when I turn off the car, and turn it back on the code will go away for some period of time....

Former User

If engine runs better with the O2 sensor unplugged, then replace the O2 sensor.

Dee_333

JEEZ, I just put a brand new one in, when I changed my oil...that was roughly less than 350 miles ago :*(

I'm pretty sure it still runs like **** when its fully warm without it plugged in though,

I even tried moving it to the lower position on my exhaust and plugged the first one. I figured maybe it would get a better reading lower down.....

I also have a crappy header that I'm pretty sure has a slight exhaust leak, could this cause these kinds of problems too? LOL!

Former User

It's pretty easy to unplug the O2 sensor and test whether the car runs better.

Definitely fix the exhaust leak. An exhaust leak will cause the engine to run rich, but it wouldn't throw code 1 or affect performance greatly.

It would help if you described exactly how you wired the O2 sensor. Be sure to mention how you matched wire colors. Did you solder and shrink wrap insulate the wires?

Dee_333

Okay, so I double checked my wiring. I think I may have had one connection not quite fully fastened down. It was running much better today and I didn't get the code my whole way home from work, which is roughly a twenty minute drive... I also reset the cel while I was in there.

Yes I heat shrinked and soldered all four wires, and using a box of those quick connectors that clamp onto an existing wire, so you can run a new wire off of it without damaging it too terribly bad....This is how I ran new wires directly off of the wires from the ecu, so I didn't have to de pin them or any of that...

Oh yeah, I wired the white wire to D14, the blk wire (heater control) to a6 the green wire to D22, and the other blk (sensor voltage) to A25 or B1 I can't remember which for sure, but I'm pretty certain it was A25...

Oh, and I don't think I even actually knew for absolutely certain which of the black wires were which....IE which black wire was for the heater control, and which one was for the voltage. maybe I got those two backwards was what I originally thought might be going on.....