O2 sensor simulator

Anyone here have experience making an O2 sensor simulator? I need to make one for “off road only” purposes for my car. I see plenty of schematics online, some much more complex than others, and im not quite sure whats better than others.

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Do you mean an o2 sensor signal fooler?
You can do it with a piece of pipe/tubing to move away the bung from the exhaust stream.

Thats what im going to try first, but i dont have a lot of room down there and my original fooler is too long to fit. i got a 90* one, but im not sure it will fit either, ill know if it does tonight, but i have a sneaking suspicion that it wont. A little circuit like this should fit anywhere I can get a small project box and some wires in to, but I want to find out if something that simple is a waste of time or not.

Have you tried extending the sensor wires and relocating the sensor elsewhere?

I haven’t thought about that, but i dont want to go welding all over my fancy new headers, They look so pretty.

I tried, didn’t work. It probably depends on how smart the car is. Some cars you can get away with installing a spacer on the 2nd O2.

You should come up with a better excuse, if you are throwing an emissions code, it’s just a light, it doesn’t cause any problems. It would make no difference in your “off road only” vehicle.

Its an “offroad vehicle” that still needs to be inspected though. Its a fairly dumb system, the car is in '04 and it doesn’t actively test the rear o2 sensors, it just looks for a signal similar to the upstream sensor a little later with a little smaller amplitude.

I’ve successfully used a spark plug defouler for this. You only need it on the secondary (downstream) O2. I used this method on an '04 Acura TSX.

I think I had to use two defoulers, the one the o2 sensor went into had to have the end drilled\cut out, then it fit into the other defouler that was installed into the o2 bung.

That was what i use to have, but i changed my exhaust setup and now theres no room to fit the sensor and the spacer/defouler.

I have seen some similar options that have a 90 elbow, to allow a low profile mount. Not sure if that would work in your situation.

I actually have 2 coming in today, but theres so little room im not sure theyll fit.

What kind of engine management are you using? Is there anyway to disable the secondary o2?

The electronic o2 simulators you are looking for are very hard to find nowadays. A few years ago, you used to be able to order them easily off Summit or Jegs, but the EPA shut that down pretty quick.

Its all factory stuff. no fancy EMS right now. thats what my other fun car is for.

Im real tempted to try this and see what happens.

I have done a similar thing with an older 1998 GMC 5.7L, not sure if it will work on a newer engine management, but it worked. The 02 sensor I had was already toast, so there was no risk for me. I’m not sure what the o2 sensor wires were made of, but they were more difficult to solder than your traditional copper wires.

im a big fan of the uninsulated crimps instead of soldering for automotive applications.

Yeah, solder does very little for a mechanical bond. Crimping is the best way to go in automotive. the capacitor and resistor might be challenging, but possible.

That’s not true at all. Soldering is great for automotive use, better in some cases but it depends on the application.

Crimping is the preferred method for automotive use. Especially when you get into custom applications and high end wiring harnesses built for race cars. You will never see soldering in those applications.

I’ve soldered plenty of automotive connections, but I’ve stopped the practice because crimping is a superior connection.

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Crimping is superior for some applications but not all.

This is 100% false.

The second o2 is the one that’s barely visible under the one that clearly visible?