Oxygen Sensor / O2 sensor simulator

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 4:19 pm

Sorry it took so long for a response, just got time today to put everything into action. After suspecting the catalytic converter and hearing everyone's suggestion to check the cat i decided to do away with it. I cut a a small section away on the bottom of the the cat with an angle grinder then chiseled all that junk out and blew it out with a blower then welded it up with a welder. I started the truck and all i can say is OMFG!! my truck actually sounds like a truck, nice rich deep grumble sound, thanks to the flowmaster super 44. After the test drive my truck appears to have better acceleration, torque, and hopefully mpg...but we'll see. Thank you everyone for your suggestions and expertise. Also to prevent the post cat o2 sensor from setting off the CEL I made a o2 sensor bypass with a 555timer and some other resistors and what not from radioshack... took a few hours to solder and figure out the correct wiring on the o2 sensor but sure enough it works. Thanks all!

Post by **HenryJ** » Fri Oct 09, 2009 4:25 pm

blakeboys wrote:... to prevent the post cat o2 sensor from setting off the CEL I made a o2 sensor bypass with a 555timer and some other resistors and what not from radioshack... took a few hours to solder and figure out the correct wiring on the o2 sensor but sure enough it works.

As Reed would say...that sounds an awful lot like FM!

I want to know more! What did you make? Details would be great.
I want one too! Can you make me one?

roadrunner · Post by **roadrunner** » Fri Oct 09, 2009 4:32 pm

I smell a new venture here!

Jongo88 · Post by **Jongo88** » Fri Oct 09, 2009 4:33 pm

X1????

Post by **HenryJ** » Fri Oct 09, 2009 4:34 pm

Of course they can not legally be sold or installed as that and gutting the cat are both illegal, as is anything that disables the emissions system.

Still, I would like to have one just to sit on the shelf and look at

Sort of a curiosity piece

roadrunner · Post by **roadrunner** » Fri Oct 09, 2009 4:38 pm

HenryJ wrote:Of course they can not legally be sold or installed as that and gutting the cat are both illegal, as is anything that disables the emissions system.

Still, I would like to have one just to sit on the shelf and look at Sort of a curiosity piece

Yeah, lots of us want a curio to sit on the mantle for looks.

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 4:53 pm

Haha no problem! i did quite a bit of searching online and finally stumbled across a link and i got a schematic for it

then went to radioshack and bought the parts. Catalog part numbers from Radio Shack stores:
(NOT for their online system)
276-309 X2 5mm wide angle red led 1.7v, 20mA $1.50
276-1723 The 555 programmable timer $1.69
276-1995* The 8 pin socket for timer chip. It makes soldering safer and replacement easier $0.48
276-150A Generic Perf PC board $1.99
64-3052 Pack of blue tap-in connectors $2.19
278-1225 Stranded wires (black, red and green) $7.99
270-1801 Small black plastic project box 3 x 2 x 1 $2.29
272-1024 Capacitor, 4.7uF $1.19
272-1026 Capacitor, 22uF $1.19

64-013 High-Tech Rosin Core Silver-Bearing Solder $5.49

100 K Ohm X2
i used a 45 watt solder iron . Pretty much it send a 0/0.7v-0.9v signal every 3.3 seconds fooling the ecu. If anyone is serious about making one of these then let me know ill go under my truck and tell you all the wires you need to splice so you can avoid the hassle of checking all 4 o2 wires to determine which color is what. Ill can also post picture of my final board results and the project box i placed it into. http://www.homemadehydrogenbooster.com/ ... ator-efie/ thats the link to the directions... and this is details of a VERY similar, if not the same device that i guy is selling..http://axistechsystems.net/oxysim.php. Also im sure glad florida doesnt do any emissions checks....id be SOL! but hell i see vehicles driving around all the time straight headers and the cops do even bother but im sure if EPA wanted to they could do something.

*****forgot about this link. This page has the same instructions and everything, the page just looks better. http://www.mkiv.com/techarticles/oxygen ... simulator/

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 4:57 pm

If you check out the picture i know it might look too simple or too good to be true but ive drove it for about 15 miles or so altogether and shutoff and turned on the vehicle about a dozen times checking my welds and still NO Service Engine Soon light!!!

Post by **HenryJ** » Fri Oct 09, 2009 5:26 pm

blakeboys wrote:...If anyone is serious about making one of these then let me know ill go under my truck and tell you all the wires you need to splice so you can avoid the hassle of checking all 4 o2 wires to determine which color is what. Ill can also post picture of my final board results and the project box i placed it into.

I'd appreciate the information.

Any chance you will be making up a few to recover your costs? Half price of the other guys?

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 5:46 pm

I got few left over capacitors. I just need to buy a perfboard and 555timer but i might make another one or two if you or anyone else is interested just to cure your curiosity of course

and ya in the process make up for cost of everything. It took me about 4-5 hrs to make the last one since i have no prior knowledge using 555timers but if i did it again i could easily do it in an hour or so. The whole project might look difficult by looking at the schematics but i redrew the schematics so instead or R1 and R2 it actually tells me what capacitor goes where. If anyone has a soldering gun and some soldering experience , even if minimal, id try to do it. I've only been soldering for about 2 years on little things here and there like laptops and such since i need them for school. Also HJ ill get that info out to everyone 2morrow or maybe sunday when im off work. That'd be the biggest help to anyone since it took me almost an hour figuring out all the resistance and voltages of the wires, kinda made me nervous cut the ecu side of the wires but all was well. I first wanted to wire this directly into the ecu but after inspecting the ecu I gave up that idea real quick but with this device you leave the o2 sensor in its place since it still has a heater. here are the pics of the o2 sensor bypass after soldering it up and after installing it inside the project box.

Post by **HenryJ** » Fri Oct 09, 2009 6:47 pm

I have no doubt that I could put one together with the information you have provided. If I can help you recoup your expenses it might save us both a buck.

Figure them out and see what you need for one. I don't have a need for one in the near future, but I will probably go the same route as you when the time comes. Mine is all bolt in now so it will be quick and painless.

F9K9 · Post by **F9K9** » Fri Oct 09, 2009 7:41 pm

Man, I tried the soldering scene again a couple of weeks ago. It was really a simple mod to stop LED rear lamps from flashing fast when using turn signals.

I doubt that I will try again!

This is over my head but, I would kick in on a new mantle display.

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 9:08 pm

I drove 35 miles tonight at 55mph and rev'd it up to 4500 rpms and still....no SES light. Sunday I'll try to make another bypass up it'll be something fun to do since have the day off. Using the left over resistors i have i only need to buy a few parts but including shipping it'll all add up to be about $25. I'm gonna be celebrating my 20th bday here in a week or so if a get some extra cash and time ill throw another one together, gives me a nice little hobby.

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 9:18 pm

Here is the schematic that I revised. This is the same as the other one that i've previously posted however instead of R1 and R2 labels i inserted the exact component name. This makes it a hell of a lot easier I promise.

Post by **HenryJ** » Fri Oct 09, 2009 9:33 pm

PM me an address and I'll send you my $25 , I can Paypal if you wish, but you lose a little to their service.
Labeling the wires , or a color code would be nice. Maybe a pictures of yours all hooked up if you get the chance.

Happy early birthday

blakeboys · Post by **blakeboys** » Fri Oct 09, 2009 9:59 pm

When i made mine i designated the power-red, ground-black, signal-green....so i can do the same..... cant get any easier. Tomorrow if I wake up early enough before i work ill check out the wires i spliced that lead to the ECU and snap a couple pictures with my phone.

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 8:35 am

I went under my truck and checked everything out. Here's the color coding for the R-G-B wires of the bypass to the trucks ecu harness of the o2 sensor: red (power) splices into the pink wire, green (signal) connects to the purple and white white leading to the ecu (leave the purple and white wire leading to the o2 sensor disconnected), the black (ground) wire splices in the tan wire, only wire that doesnt get used is the brown wire I believe, and i think thats used for the heater. Here are some more pictures of my whole setup and a picture of my cluster panel while my truck is running...

ya i used way to much wire here but better too much then too little

Post by **HenryJ** » Sat Oct 10, 2009 8:58 am

Do you think that there is enough length in your wiring from the box to route it up into the engine compartment?
I do some deep water crossings and I am afraid I would have that box swamped.
If not , maybe put it in the rear cab corner and route the wires down to the connection.

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 9:07 am

I could run enough wire to allow it to be place in the rear of the cab. I first wanted to place it under the hood directly into the ecu but there were soo many wire I didn't have the patience to test them all but if u or anyone else knows which pins are the power, ground, and signal then we could both put it under the hood

Post by **HenryJ** » Sat Oct 10, 2009 10:21 am

I have the wiring diagram for the PCM, but I don't like that idea. Too easy to cause a problem. Plug-n-play at the sensor connector is a better idea.
Seems like there might be a body plug in the floor board where the wires could be routed.

Horsehammerr · Post by **Horsehammerr** » Sat Oct 10, 2009 1:06 pm

Do you think all three O2 sensors could be fixed this way ?

Post by **HenryJ** » Sat Oct 10, 2009 1:11 pm

You really need the two front sensors to control engine function. The post cat sensor is only there to tattle on a cat that is out of performance specs.
While you could probably substitute the front sensors with one of these, it might not be such a good idea. The PCM really does need to know when it is rich or lean.

Horsehammerr · Post by **Horsehammerr** » Sat Oct 10, 2009 2:45 pm

My SES light has been on for over a year now. I had the code read and it is the left bank O2 sensor. I've done nothing about it and all is well. It just bugs me to have that red light glaring in my face all the time, specialy at night.

F9K9 · Post by **F9K9** » Sat Oct 10, 2009 2:53 pm

Horsehammerr wrote:My SES light has been on for over a year now.......

My worry would be what else is the O2 code hiding. I have a code reader and I would continually keep checking it. Other codes could be hiding behind that light. Then, of course, you know my luck and why I panic at the mere sound of a single quack.

Post by **HenryJ** » Sat Oct 10, 2009 3:09 pm

Horsehammerr wrote:My SES light has been on for over a year now. I had the code read and it is the left bank O2 sensor. I've done nothing about it and all is well.

I would fix it. You can drive on the default values and might do Ok. It will likely be more efficient using data from the O2 sensors though. I don't know which default values it uses, but without readings from the sensor it will not adjust quickly to compensate for changing conditions.
You can drive without the MAFS connected too, as with other sensors. It may not run to its full potential though. I would fix that sensor of yours. That is just me though.

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 5:39 pm

I 2ND THAT! Replacing the sensor would be a good idea if it's dead. Even if you use this bypass you still need the o2 sensor since our o2 sensor has a heater which the ecu can also detect as resistance i believe... But other than that another day has gone by and the short drive to work and back (~10 miles) I still have no SES light.

Post by **HenryJ** » Sat Oct 10, 2009 6:08 pm

Now just a second. This sim still needs a functioning sensor to provide the heater circuit?
That seems a little strange. There must be a way to bypass or simulate that too.
What I envision is this simulator plugging into the harness in place of the stock sensor. I assume that is not the case right now?

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 6:15 pm

Nooo I didn't try disconnecting the o2 sensor completely...I just spliced into the ground, power and cut the o2 sensor signal cable going to the o2 sensor and connected my signal wire into the o2 sensor signal wire leading to the ecu. It might work either way but from what I've read the ecu can still tell if there's resistance from the heater...

From:http://www.mkiv.com/techarticles/oxygen ... simulator/ The original sensor should still be dangling around, or plugged into the downpipe. The reason is that ECU also monitors the resistance of heater circuit inside the sensor. If you want to COMPELTELY disconnect it, you will need to measure the resistance of the heater circuit and install the right resistor between ECU PIN #72 and ECU PIN #31 Anyway, there is no need to do it if you just leave O2 sensor alone and only intercept the oxygen signal wire.

Post by **HenryJ** » Sat Oct 10, 2009 6:36 pm

Ok, then the box does need a resistor. All that is needed is to have the correct resistance to simulate the heater.

This really needs to be "plug and play", it could even be markets as a diagnostic tool if you don't have to cut or disable a working sensor.
My sensor is working just fine and I am not going to want to cut the wires on it.

Any chance you can either find or test the resistance and add a resistor to the box?

It looks like the MIL should illuminate at the first failure. There is no threshold to exceed. It takes 40 ignition cycles to clear the code, but only three successive to shut the light off.

I don't see resistance values listed yet.

Wiring for the HO2S (Bank1 sensor2):
Pin A - TAN/WHT = Low signal
Pin B - PPL/WHT = High signal
Pin C - BRN = Ground
Pin D - PNK = Ignition 1 Voltage (hot in run and start)

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 9:07 pm

HenryJ wrote:...
Wiring for the HO2S (Bank1 sensor2):
Pin A - TAN/WHT = Low signal
Pin B - PPL/WHT = High signal
Pin C - BRN = Ground
Pin D - PNK = Ignition 1 Voltage (hot in run and start)

Huh.... guess i should have asked you before doing this project... so i grounded my bypass's black ground wire to the tan wire only because i tested for continuity and the tan grounded out and the brown did not so I figure the brown had to be a heater wire. This is odd i guess because my bypass is working great I even made a quick video of it working. The video is from my cell phone so its not the best but you can clearly see the stable led indicating power then another dimmer one to the top right flashin about every 3.3 seconds or so.... Wondering if I should switch my ground to the brown wire and measure the resistance between the tan and brown? I also found this device someone made. It contains the very information we may need. The resistor looks legit, using 4 resistors would easily simulate an o2 heater and dissipate the heat. What do you think? http://www.dsmtuners.com/forums/article ... lator.html

Post by **HenryJ** » Sat Oct 10, 2009 9:14 pm

blakeboys wrote:...using 4 resistors would easily simulate an o2 heater and dissipate the heat. What do you think?

Looks like it worked. Sure worth a shot.

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 9:24 pm

yes and after reading everything displayed here http://www.o2simulator.com/doc/o2sim_in ... manual.pdf I'm convinced. This page states that if you want totally remove the o2 sensor then they use a 20ohm/20 watt resistor and give pictures too.... sounds like your problem there is solved! I'd still go with 4 50ohm/10 watt ones though just to be safe because they state that there 20ohm/20 watt resistor heats up very hot and to keep it away from flammable stuff....so ya that's enough to convince me to use the other method. Also the reason my box is working is because the tan wire is a ground for the heater i think.... Im really just going by what i've read on the pdf posted above.

blakeboys · Post by **blakeboys** » Sat Oct 10, 2009 9:30 pm

HenryJ wrote: My sensor is working just fine and I am not going to want to cut the wires on it.

I didn't cut my o2 sensor wire because just in case this device turned out to a total waste i still wanted to have a functional o2 sensor. I simply splice into the ecu side of the o2 wires. Therefore i could easily revert back if I ever had the need. But now with this resistor idea it really doesnt matter. Just have to find the o2 sensor connectors online and we're good to go.

Post by **HenryJ** » Sat Oct 10, 2009 9:37 pm

I have a few old sensors around, so I'll probably use those connectors until I get a chance to look up a source for new ones.

Horsehammerr · Post by **Horsehammerr** » Sun Oct 11, 2009 2:25 am

Which one eliminates or bypasses the O2 sensor completely?

blakeboys · Post by **blakeboys** » Sun Oct 11, 2009 5:52 am

blakeboys wrote:... http://www.dsmtuners.com/forums/article ... lator.html

Well the bypass i made using the schematics a couple posts up will work to bypass the sensor part of the o2 sensor. Then following the link I in my quote above will show you a design for a heater bypass that should work. Put all these things together you could essentially eliminate the o2 sensor completely.

roadrunner · Post by **roadrunner** » Sun Oct 11, 2009 8:09 am

I've been doing quite a bit of study and reading on the O2 sensor/pcm system lately and feel the need to interject a word of warning here. The sim being discussed here will work for the after cat sensor but SHOULD NOT BE USED for the front sensors on our trucks. That third sensor is only to monitor cat efficiency and has no bearing on the pcm other than to turn on the SES light if it is malfunctioning or an out of range condition is detected.
The front two sensors are used for fuel management and replacing/disabling them could result in either engine damage due to over lean or over rich condition or poor fuel economy due to pcm reverting to preset values internally. These two sensors need to remain functional in order to adjust the fuel management for changing loads and conditions.
If anyone wants to change or otherwise adjust the functioning of the front two sensors there are companies on the web selling devices which will do this by adding preset voltage to the signal wire of the sensors. This has the effect of telling the pcm the engine is running richer than it really is and will cause the pcm to lean out the fuel input accordingly depending on the amount of voltage added.
Additional information/reading as well as products can be found here: http://www.fuelsaver-mpg.com/store/ as well as many other sources. Many of them associated with hydrogen generation systems for vehicles. That is where I "sidetracked" onto them.

blakeboys · Post by **blakeboys** » Sun Oct 11, 2009 8:13 am

Well said...

Post by **HenryJ** » Sun Oct 11, 2009 4:15 pm

I just checked and I have three used sensors in the garage.
All were functioning, but I could salvage the connectors as they have no sentimental value

DLP · Post by **DLP** » Wed Oct 14, 2009 5:48 pm

This would be too cool if it stays working. I have a few of the 555 chips. My boy and I use to make Christmas tree light blinkers with them. I will round them up and Hide-N-Watch this thread.

blakeboys · Post by **blakeboys** » Sat Jan 09, 2010 9:15 pm

Still working....

Post by **HenryJ** » Sat Jan 09, 2010 9:21 pm

blakeboys wrote:Still working....

Thanks for the update!
Made any extras yet?

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Oxygen Sensor / O2 sensor simulator

Re: Oxygen Sensor / O2 sensor simulator

Re: Oxygen Sensor / O2 sensor simulator