single wire o2 conversion to 3/4 (heated)

[getnpsi]

This was discussed on one of the other boards i frequent. Has anyone added this to their 1980s/1990s obd cars and experienced a smoother running during warmup? I think with the colder weather setting in the faster we can get into closed loop the better. My only question, is if the o2 heater is running off 12v or another voltage i have to find (or make) elsewhere in the car? I know that with a single wire sensor, the sensor housing itself is the ground like a spark plug, and it has it's own signal to carry back to the ecu.

[some_other_dave]

The three-wire O2 sensor will have the signal wire, a power wire, and a ground wire. Hook up those wires to the appropriate things and it should work nicely.

I don't recall if the ground wire is only used to ground the heating element (likely IMHO) or if it also grounds the O2 circuit itself. I think you'd get more variation in the reading with the heating if the ground wire was shared by the sensor and the heater, so I'm guessing that the sensor would still ground through the threads into the exhaust pipe.

I am less sure, but I think a four-wire sensor has heater power, heater ground, signal wire, and sensor ground wire.

-soD

[getnpsi]

After doing a search, i found that on those more modern vehicles, the ecu does the grounding. Im not sure which 4 wire systems have that property and which do not so i think im better off scoring a 3 wire. It's cheaper at the store anyway. I think i have some 3 wires used at home. Im going to install one of those and if my car behaves the same or better then great. if not then at least i have the oem plug installed and can replace with ease.

[Dust]

subscribing

[trebuchet03]

Originally Posted by getnpsi

My only question, is if the o2 heater is running off 12v or another voltage i have to find (or make) elsewhere in the car?

From my previous experimentation and failures.... Yes, it's 12V

[Red]

12v ftw

[metalshark]

I can pretty much guarantee that the more wire running from the o2 sensor the better. looking into wideband o2 sensors I have found that they are used for the ecu or ecm to be able to control the Air to fuel ratio that way efficiency is at its peak.

its all depending on how much your willing to work on it.


never ground to an exhaust pipe unless you want a small fire under the hood the exhaust pipes reach over 600 degrees Fahrenheit.

[getnpsi]

o2 sensor is really stuck in the manifold. i have an o2 sensor socket but its a cheapo brand and really starts to bend when i apply a lot of force. Im not going to remove the radiator just to get my impact in there. It's not THAT important

[Coyote X]

It depends on the ECU if it is going to help anything with warmup smoothness. But if you do engine off coasting the 1 wire sensors cool down quick and take a few minutes to warm back up even if the engine is at full temp while driving easy. I would suggest using a 4 wire sensor and running the ground back to the ecu to get a lot more accurate signal. On an OBD1 Metro as soon as the water is over 110 degrees I think, and the sensor is reading the car then starts using it.

4 Wire Oxygen Sensor–MetroXFi.com

lot more info on switching to a 4 wire sensor there.

[getnpsi]

Yes, for the engine off coasting is why i was addressing the add-on. where i live, we do not get under 40 degrees during the day ever so many of you probably wonder why I even bother with additional "warm-up" techniques, but if i have free parts lying around why not.

[some_other_dave]

Originally Posted by getnpsi

o2 sensor is really stuck in the manifold. i have an o2 sensor socket but its a cheapo brand and really starts to bend when i apply a lot of force.

Spray it with PB Blaster or Aero Kroyl. (WD-40 is not a penetrating oil and is all but useless for loosening stuck bolts IMHO.) Slip the wires through a six-point box-end side of a combo wrench and get that on the sensor body. Get a looooong combo or box-end wrench and hook the box end onto the open end of the first wrench. Push with one hand, use the other to tap the first wrench with a heavy hammer. The sensor will let go...

-soD

[orange4boy]

o2 sensor is really stuck in the manifold.

Also O2 sensor is simpler to remove when hot. Wear some leather gloves and protective sleeves tho.

[getnpsi]

if it were only that easy. On this car, its very difficult to get any leverage with the box end, without taking out the radiator. I have an extra exhaust manifold i could install...but again the PITA factor of radiator removal. The hoses are old LoL. Me and my 700 dollar cars. ill shoot it with pb and let it sit overnight. Last time i only let it sit an hour or two because i work in the late afternoon.

[orange4boy]

Can you get a bigger box wrench on the end of the other to add length? Put the open end through a bigger box and link them together If there's room. Give the base of the o2 a good few whacks with a hammer and chisel or something long and steel. Also try to heat the o2 with a propane torch and get it good and hot then let it cool off. This crushes the rust in the thread.

That's all my tricks.

[getnpsi]

Well ive rounded the outside kinda bad using the stupid kragen autoparts socket. The regular 22 box end wrench holds fine still, but just not enough leverage. Theres really no range of motion to strike it that soundly. I tried the end of the floorjack for both leverage and as a pipe to hit with and things just slip around. I can get it off if the manifold was off the car...cut the o2 wire, hammer the wrong size impact on there and zap zap she's off...bu't cant do that to my daily driver. Dissasembly with care vs junkyard dogging are two different animals.