O2 Simulator - New schematic and pictures
04-22-2009, 10:39 AM
#1
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Join Date: Sep 2008
Location: Florida
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O2 Simulator - New schematic and pictures
Hey guys,
I have talked in a couple of threads before about removing the cats and needing o2 (oxygen) sensor simulators to remove the pesky check engine light (MIL). I finally got around to spending a little time on it and I figured I would share my info.
First off I started with info gathered from:
http://www.mkiv.com/techarticles/oxy...sor_simulator/
I wasn't 100% happy with the way he had drawn the schematic, so I made my own. It (to me atleast) seems to flow more of the way you have to lay it out. While keeping all components in correct order.
So I have built it on a breadboard (2 simulators on the same board) and it looks like this:
I have tested it (not in the car yet) and it puts out 0.1/0.7 (swapping voltage every few secs) when the car is off (12V) and 0.1/0.9 when the car is running (14v+).
Seems like it should work, eh? I also picked up some non-inductive resistors to simulate the heat circuit (not pictured).
Will probably hook up to my car today and see what it does. If all is well I will solder it up on a board.
Hope this info helps someone.
I have talked in a couple of threads before about removing the cats and needing o2 (oxygen) sensor simulators to remove the pesky check engine light (MIL). I finally got around to spending a little time on it and I figured I would share my info.
First off I started with info gathered from:
http://www.mkiv.com/techarticles/oxy...sor_simulator/
I wasn't 100% happy with the way he had drawn the schematic, so I made my own. It (to me atleast) seems to flow more of the way you have to lay it out. While keeping all components in correct order.
So I have built it on a breadboard (2 simulators on the same board) and it looks like this:
I have tested it (not in the car yet) and it puts out 0.1/0.7 (swapping voltage every few secs) when the car is off (12V) and 0.1/0.9 when the car is running (14v+).
Seems like it should work, eh? I also picked up some non-inductive resistors to simulate the heat circuit (not pictured).
Will probably hook up to my car today and see what it does. If all is well I will solder it up on a board.
Hope this info helps someone.
Last edited by MikeInCape; 04-24-2009 at 02:04 PM.
04-24-2009, 02:11 PM
#3
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Join Date: Sep 2008
Location: Florida
Posts: 172
Wohooo! My homemade O2 Simulators Work! 
Got up the energy to go out into the heat, and hook up my breadboard O2 (Oxygen) Sensor Simulator I made. Took a little while just to get to everything, and find the right wires, and take my time. But here are a few pics.
I ran the car for a good long while, and past when the check engine light came on. Went home, checked codes, and only O2 Heat Circuits now!
I will be soldering up my board here soon, and will post pics when done.
(Also for some reason P1260 which is 4x4 trans switch malfunction. I have been getting this code since I got the car. Anyone have any ideas on that? lol)
Now I am ready to put in my O2 Heat Circuit "Simulators". One article I read recommends 10ohm 20watt Non-Inductive Resistors. I could only find 8ohm 20 watters at RadioShack. Wonder if these will work? I've also read somewhere else of using something different. Any suggestions here?
Got up the energy to go out into the heat, and hook up my breadboard O2 (Oxygen) Sensor Simulator I made. Took a little while just to get to everything, and find the right wires, and take my time. But here are a few pics.
I ran the car for a good long while, and past when the check engine light came on. Went home, checked codes, and only O2 Heat Circuits now!
I will be soldering up my board here soon, and will post pics when done.
(Also for some reason P1260 which is 4x4 trans switch malfunction. I have been getting this code since I got the car. Anyone have any ideas on that? lol)
Now I am ready to put in my O2 Heat Circuit "Simulators". One article I read recommends 10ohm 20watt Non-Inductive Resistors. I could only find 8ohm 20 watters at RadioShack. Wonder if these will work? I've also read somewhere else of using something different. Any suggestions here?
Last edited by MikeInCape; 04-24-2009 at 02:25 PM.
04-24-2009, 02:34 PM
#4
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04-24-2009, 02:36 PM
#5
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Join Date: Sep 2008
Location: Florida
Posts: 172
Hmmm... Thinking about this heat circuit, I definitely need more info.
I am going to start my internet search, but if anyone on here knows, I would appreciate some help.
1. What is the best component to use to achieve the correct resistance on the sensor wire for the heater circuit?
2. Is the computer sensor wire a ground, like the sensor itself is? Meaning, do I connect 12V to one end of my resistor and the heat sensor wire to the other?
Thanks in advance guys.
I am going to start my internet search, but if anyone on here knows, I would appreciate some help.
1. What is the best component to use to achieve the correct resistance on the sensor wire for the heater circuit?
2. Is the computer sensor wire a ground, like the sensor itself is? Meaning, do I connect 12V to one end of my resistor and the heat sensor wire to the other?
Thanks in advance guys.
04-24-2009, 02:38 PM
#6
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Join Date: Sep 2008
Location: Florida
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Thanks nerd, but I do not believe this page answers what I need. I have read over it. He is leaving the sensor in and using its heater circuit. I have no sensors, therefore no heater circuit.
He is even using the sensor for the "sensor data" (voltage) then modifying it... Novel idea, but sensors cost $$$ and a resistor is cheap.
Last edited by MikeInCape; 04-24-2009 at 02:45 PM.
04-24-2009, 02:59 PM
#8
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Join Date: Sep 2008
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If you are asking why did I build a board and not use my sensors with the other guys mod. When I got my new O/R x-pipe my sensors wouldn't come out of my old one. So I never bought any back ones.
If you are asking why put the components on a board and not wire them up... It has a timer chip in it... Has to be on a board. Can't really just solder that up like the other guy did the the resistor. I am going to solder on a real pc board soon. Just built in the breadboard to test.
04-24-2009, 07:25 PM
#10
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Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Simulating the heater circuit is not a trivial task. The heaters have a cold resistance of 3.3Ω, which actually falls a bit as they heat. 13.8V across 3.3Ω = 4.2A = 58W which is not an inappreciable amount of power (most small, cheap, soldering irons are 25W).
Some years ago I approached this issue with a newer Miata with 6.0Ω heaters (33W) and we resolved it with a 10Ω 30W resistor. This was an $18 part from Jameco.
If I were to attack it again I'd start with the 10Ω 30W resistors and see if the PCM could deal with it. A word of caution however--these puppies will get HOT (remember that 25W soldering iron I spoke of earlier?). They need to be mechanically mounted to a solid surface--not taped to "something" nearby--preferably where there is some airflow.
Some years ago I approached this issue with a newer Miata with 6.0Ω heaters (33W) and we resolved it with a 10Ω 30W resistor. This was an $18 part from Jameco.
If I were to attack it again I'd start with the 10Ω 30W resistors and see if the PCM could deal with it. A word of caution however--these puppies will get HOT (remember that 25W soldering iron I spoke of earlier?). They need to be mechanically mounted to a solid surface--not taped to "something" nearby--preferably where there is some airflow.