Obx header O2 sensor

[Sonyps307]

On the obx header the o2 spot is moved how can I go about making the wire longer

[907mge]

Don't make the wire longer. Move the sensor up further closer to where it should be. Probably around the area where the two pipes merge to one. I have the pacesetter which is the same except it is made out of mild steel instead of stainless and it will kick the cel on about once a week and give the same code.

http://www.toyota-supra.info/forums/...ce-please.html

[Sonyps307]

So what did u have spot moved up by a shop and I didnt think the wire would reach to there

[907mge]

The wire will still have to be lengthened. But it will be way closer than down it front of the cat. I have not moved mine since I didn't get time last year before it got cold. Its a project for this year. But using heat wrap is a must to keep the heat down unless you get it ceramic coated, which is expensive.

[cre]

You never want to extend the wiring of a narrowband sensor if at all possible. If you do extend it do some research on the wire and crimps available before buying (to avoid significant voltage drop and prevent dielectric spiking) and test the results against a calibrated wideband.

Moving the sensor further downstream isn't a good idea either as it may not stay at the required temp unless you take measures to keep the heat in the exhaust system... and even then it may still be too cool. You could install a heated narrowband like the GTE uses though.

With that all said, I've had good luck on two installs by cutting the wire off of an O2 sensor and then crimping a new, harness side connector bought from my local Toyota dealer.

That header looks like they were references a Cali spec MKIII and only accounted for the secondary sensor.... I'm surprised they've never fixed it, I'm sure they get plenty of comments.

[907mge]

Yeah I was wondering about the effects of just having a longer wire alone since mine is extended by about 4ft. to reach. And then with the sensor being so far down versus the oem location right by the head, I think my mpg s are suffering because of it. Its a project for the spring to move it.
How low can the exhaust temps drop in 3ft.?

[cre]

4 FEET?!
That's WAY too long. The method you used to extend it may have made it worse too... You never want to solder a low voltage/small signal wire. I wouldn't try extending it more than a foot or damn near.

In three feet exhaust can loose a lot of energy. Think about it this way... on a very free flowing exhaust the air coming out of the muffler probably is still under 200?; It leaves the head around 1400?; Average combustion temps are around 1600-1700?.... That's a BIG drop and VERY fast.

Widebands aren't anywhere near as touchy, but I once had to move one because it was overheating in the stock location... we didn't move it more than a foot and it was fine. The first four feet or so are where the exhaust sees the biggest drop in temperature after leaving the cylinder. But, as mentioned, the heat thing isn't the biggest issue just wire in a heated sensor instead.

The nice thing with widebands is that they're full scale and use a much wider voltage range, a minor drop isn't going to affect much; Narrowbands on the other hand use a signal between .3 and .6 volts to declare an optimum mixture... outside of that range the ECU gets no usable information at all.

[Sonyps307]

If I don't extend it longer then a foot of wire and crimp the wires. Then move the o2 sensor closer to the stock position. U think it would work right then. Also maybe I could go to the junk yard and get the 2 plugs for the o2 sensor and make a extension wire so I don't have to cut my o2 sensor and just plug and play.

[cre]

WTF??? Dude... my relatives in Europe speak better English, and the older ones don't speak it. If it's not your native language then I suggest you start using Google Translate, I'm not replying to posts like this anymore.

[Sonyps307]

Here cre do u understand it now