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Question about o2 simulators

Old 12-23-2018, 03:25 PM
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Originally Posted by SquidBeak View Post
No touchscreen? No WIFI?

What is this crap?

Seriously, this is great. I hope it works.

You probably know this, but if you have a bluetooth OBDII adapter and an app like Torque, you can graph the output of your sims and see what they're doing. That would be cool to see.

Good luck. Keep us posted
I have an iphone and thus the torque app is unavailable to me, although i see something similar on the app store for $10. I do, however, have a laptop with NDS2 - anyone happen to know offhand if NDS2 can monitor secondary O2 sensors?

Heres some technical jargon that you definitely dont need to understand to do this yourself; this device is supposed to output a square wave that fluctuates from 0.1V - 0.4V to 0.6V - 1.2V. What the exact values dont really matter (at least as far as i understand) - what matters is that the ECU is seeing the fluctuation, and that the wave is square, meaning the output voltage is always either below the minimum value (0.4V) or above the max value (0.6V) of the “no go” voltage range. However, if the wave produced was, for example, a sin wave, it would have the same min/max voltages, but would also very briefly cross into the “no go” 0.4V - 0.6V range. If that were to occur, it is my understand that the ECU interprets that signal as signifying the exhaust has too many hydrocarbons and therefore throws a code.

Back to the point - The 555 timer (name of the IC chip this device uses) along with the capacitors, resistors, and diodes simulates that nice square wave we are looking for. As stated the exact values at the top and bottom of the square wave shouldnt matter, as long as they are within the required ranges. With an actual O2 sensor i understand that youd see all sorts of different voltage ranges, but as long as the limits of those ranges never fall between 0.4V and 0.6V the ECU is happy. With the simulator, you will get a fixed range as the input voltage is never changing as it would be with a real sensor. For us this isnt a problem, as the ECU isnt smart enough to look for a random variety of voltage minimum/maximums. However i could definitely see car manufacturers in the future (if they arent already) making ECUs that wont accept a fixed voltage range that a sim produces and requiring a random voltage range that a sensor produces.

Anyways, TLDR / TMI for most of you reading. The prototype i made today follows the schematic (in one of my previous posts) that i found all over the internet that people have had success with. Id bet anything that it is going to work, my only uncertainty is whether or not one sim circuit can satisfy the signals of both sensors. We shall see!

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Old 12-23-2018, 05:27 PM
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Originally Posted by Slamrod View Post


I have an iphone and thus the torque app is unavailable to me, although i see something similar on the app store for $10. I do, however, have a laptop with NDS2 - anyone happen to know offhand if NDS2 can monitor secondary O2 sensors?

Heres some technical jargon that you definitely dont need to understand to do this yourself; this device is supposed to output a square wave that fluctuates from 0.1V - 0.4V to 0.6V - 1.2V. What the exact values dont really matter (at least as far as i understand) - what matters is that the ECU is seeing the fluctuation, and that the wave is square, meaning the output voltage is always either below the minimum value (0.4V) or above the max value (0.6V) of the “no go” voltage range. However, if the wave produced was, for example, a sin wave, it would have the same min/max voltages, but would also very briefly cross into the “no go” 0.4V - 0.6V range. If that were to occur, it is my understand that the ECU interprets that signal as signifying the exhaust has too many hydrocarbons and therefore throws a code.

Back to the point - The 555 timer (name of the IC chip this device uses) along with the capacitors, resistors, and diodes simulates that nice square wave we are looking for. As stated the exact values at the top and bottom of the square wave shouldnt matter, as long as they are within the required ranges. With an actual O2 sensor i understand that youd see all sorts of different voltage ranges, but as long as the limits of those ranges never fall between 0.4V and 0.6V the ECU is happy. With the simulator, you will get a fixed range as the input voltage is never changing as it would be with a real sensor. For us this isnt a problem, as the ECU isnt smart enough to look for a random variety of voltage minimum/maximums. However i could definitely see car manufacturers in the future (if they arent already) making ECUs that wont accept a fixed voltage range that a sim produces and requiring a random voltage range that a sensor produces.

Anyways, TLDR / TMI for most of you reading. The prototype i made today follows the schematic (in one of my previous posts) that i found all over the internet that people have had success with. Id bet anything that it is going to work, my only uncertainty is whether or not one sim circuit can satisfy the signals of both sensors. We shall see!

It can. I still have sims and the only difference between single and dual output is another wire on the pad.
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Old 12-23-2018, 10:23 PM
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Originally Posted by Child_uv_KoRn View Post
It can. I still have sims and the only difference between single and dual output is another wire on the pad.
do you know what IC chip your simulator uses? A long while back i read something that said exactly what you are saying. However tonight i read that for a dual output simulator you need to use a 556 timer rather than a 555 timer, its basically just a IC chip that has two 555’s built into it.

Still gonna test it with just the single 555 chip for both outputs because it cant hurt, but if you can verify your setup uses a single 555 that would definitely bring me a little more ease knowing i dont have to go throw the tedious bs of building another one of these damn things.
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Old 12-24-2018, 04:22 AM
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Originally Posted by Slamrod View Post


do you know what IC chip your simulator uses? A long while back i read something that said exactly what you are saying. However tonight i read that for a dual output simulator you need to use a 556 timer rather than a 555 timer, its basically just a IC chip that has two 555’s built into it.

Still gonna test it with just the single 555 chip for both outputs because it cant hurt, but if you can verify your setup uses a single 555 that would definitely bring me a little more ease knowing i dont have to go throw the tedious bs of building another one of these damn things.
HV615-1 http://www.mouser.com/ds/2/268/41302A-49594.pdf
Pin out doesn't match, though. I think it's programmed to trick most ECUs as it oscillates. I thought it was a dumb one.

Last edited by Child_uv_KoRn; 12-24-2018 at 04:27 AM.
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Old 12-26-2018, 12:17 PM
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too bad they make a simulator that can take the out the from the O2s and modify it a little bit so the ECU isn't completely blind and can compensate when actually needed. (without a whole ****ty *** piggy back ECU)
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Old 12-26-2018, 12:30 PM
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Originally Posted by cdoublejj View Post
too bad they make a simulator that can take the out the from the O2s and modify it a little bit so the ECU isn't completely blind and can compensate when actually needed. (without a whole ****ty *** piggy back ECU)
That's what the area74 sims do. Also, depending on the specific objective (eliminate DTCs or pass emissions tests) the ECU can be flashed to accomplish this. I'm running primaries only, have no CEL but my readiness monitors won't set. I don't have emissions to pass so I can live with that
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Old 12-26-2018, 02:19 PM
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I've been reading up on gutting my pre-cats for a while now, and want to do it soon. My Max has been sitting in the driveway for over a year now because of the fear of pre-cat failure. I was wondering if I were to use an O2 extender/non-fouler, what would be the minimum length to get? I suppose it also depends on available clearance gap too, right?
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Old 12-26-2018, 05:46 PM
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Originally Posted by freezer View Post
That's what the area74 sims do. Also, depending on the specific objective (eliminate DTCs or pass emissions tests) the ECU can be flashed to accomplish this. I'm running primaries only, have no CEL but my readiness monitors won't set. I don't have emissions to pass so I can live with that
ONLY 5.5 gen ECU can be flashed unless you can get binary tuning him self to flash/tune your 5.0 Gen which no one but, me runs. are the area 74 sims discontinued or can i still get them? how many body parts do they cost?
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Old 12-27-2018, 11:38 AM
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Originally Posted by cdoublejj View Post
ONLY 5.5 gen ECU can be flashed unless you can get binary tuning him self to flash/tune your 5.0 Gen which no one but, me runs. are the area 74 sims discontinued or can i still get them? how many body parts do they cost?
their website is still up (someone linked earlier in this thread) so i am assuming they still sell them. However $120 for a sim is absolutely crazy. Also i find their claims to be utter bullsht on a few areas. 555 timer based sims work absolutely fine and are pretty much the standard; the website claims they “might” be unreliable for some newer cars, but fail to give any examples of where a normal sim fails and theirs does not - its a claim with zero supporting evidence that convienently makes it seem that their product is a must. They do acknowledge 555timer based sims work on older cars (and i suspect most cars) which our cars certainly are, so right there is good reason to not buy from these people.

They also claim using a defouler/extender is “difficult to get just right” and “requires routine maintanence”. That is misleading at best. I used defoulers on my previous cars and never had any issues ever. How installing a defouler could be considered “hard” is beyond me.The only reason not to use a defouler is if you are removing your secondary o2s entirely. It appears they also claim their device modifies the o2 signal rather than replacing it entirely - if you have to keep the sensor than whats the point of simulating it in the first place? Itd be easier and a hundred times cheaper to simpley run a refouler in that case. Finally they show a graph that has little to no context that vaguely states it is data collected from a “chrystler product”. It compares a working sensor to their simulator. Thats nice, but after all these claims how their sim works and others dont, where is the graph comparing their sims and others? Again no evidence.

Idk about you guys but that website reeks of bs. The fact they lie and claim you must buy a seperate simulator for each sensor just ices the cake. Im extremely interested to see what is underneath that housing.
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Old 12-27-2018, 12:58 PM
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Originally Posted by Jagalag View Post
I've been reading up on gutting my pre-cats for a while now, and want to do it soon. My Max has been sitting in the driveway for over a year now because of the fear of pre-cat failure. I was wondering if I were to use an O2 extender/non-fouler, what would be the minimum length to get? I suppose it also depends on available clearance gap too, right?
I cannot find the link for what I bought but these look identical.
Amazon Amazon
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Old 12-27-2018, 01:43 PM
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Originally Posted by Slamrod View Post


their website is still up (someone linked earlier in this thread) so i am assuming they still sell them. However $120 for a sim is absolutely crazy. Also i find their claims to be utter bullsht on a few areas. 555 timer based sims work absolutely fine and are pretty much the standard; the website claims they “might” be unreliable for some newer cars, but fail to give any examples of where a normal sim fails and theirs does not - its a claim with zero supporting evidence that convienently makes it seem that their product is a must. They do acknowledge 555timer based sims work on older cars (and i suspect most cars) which our cars certainly are, so right there is good reason to not buy from these people.

They also claim using a defouler/extender is “difficult to get just right” and “requires routine maintanence”. That is misleading at best. I used defoulers on my previous cars and never had any issues ever. How installing a defouler could be considered “hard” is beyond me.The only reason not to use a defouler is if you are removing your secondary o2s entirely. It appears they also claim their device modifies the o2 signal rather than replacing it entirely - if you have to keep the sensor than whats the point of simulating it in the first place? Itd be easier and a hundred times cheaper to simpley run a refouler in that case. Finally they show a graph that has little to no context that vaguely states it is data collected from a “chrystler product”. It compares a working sensor to their simulator. Thats nice, but after all these claims how their sim works and others dont, where is the graph comparing their sims and others? Again no evidence.

Idk about you guys but that website reeks of bs. The fact they lie and claim you must buy a seperate simulator for each sensor just ices the cake. Im extremely interested to see what is underneath that housing.

Here have a read this guy isn't wrong.

https://motoiq.com/piggyback-ecus-ar...r-your-health/

it also echos the sentiment of older N/A cars not being as big of a deal. a reprogram of thE ECU is right and proper vs lieing to it till you get what you want. i'd quite possibly keep CEL light on vs emulate/simulate the o2 signal together, now one that modifies
that signal so it's not compeltley lieing the ECU would be a nice stop gap until the real deal ECU tune.
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Old 12-27-2018, 05:18 PM
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Originally Posted by Slamrod View Post

...Im extremely interested to see what is underneath that housing...
Inside the housing, the circuit board is covered in epoxy, but I can't remember if it's clear or black. If it's clear and the components are visible, I'll take a pic and post it.
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Old 12-27-2018, 09:30 PM
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Originally Posted by cdoublejj View Post
Here have a read this guy isn't wrong.

https://motoiq.com/piggyback-ecus-ar...r-your-health/

it also echos the sentiment of older N/A cars not being as big of a deal. a reprogram of thE ECU is right and proper vs lieing to it till you get what you want. i'd quite possibly keep CEL light on vs emulate/simulate the o2 signal together, now one that modifies
that signal so it's not compeltley lieing the ECU would be a nice stop gap until the real deal ECU tune.
Great article! Thanks for posting that. Very concise and informative. That's just the kind of read that gets my gears turning.
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Old 12-28-2018, 03:51 AM
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Originally Posted by TallTom View Post
I cannot find the link for what I bought but these look identical. https://www.amazon.com/Universal-Ada...YEYWEC0PPQDJFY
so just to confirm, 46mm length would be ok to use? I can see it fitting in the front, but I don't know about the rear yet. I was thinking an angled or 90 degree spacer might make more sense there...no?
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Old 12-28-2018, 06:43 AM
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jagalag, go for the spacer, let us know ! if not worst case you can get a sim if the extender / spacers dont do the trick.

and so this board you made its a sim? crazy ! nice work.
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Old 01-01-2019, 09:13 PM
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Decided to slim down the board design. With lots of tedious effort of laying solder tracks and carefully rearranging components, i managed to shrink the layout down to nearly half the footprint of my previous layout. I think this is basically small as humanly possible to make this thing without using smd components.






As you can see its a very tight fit. Unless you are **** as i am about making it small (discrete) as possible, i wouldnt go through the trouble. The solder tracks on the back were very difficult because i did not have a mini vice to hold the board still, nor a soldering iron with accurate temperature control. One thing that is driving me MAD is that i did not account for the second signal wire in this design. Of course, im just going to link the second signal wire to the first one rather than solder it to the board itself, but considering how clean i made this damn thing its frustrating to have to resort to some ghetto rigged crap like that to make it happen. I suppose its a moot point since im going to stick it inside a housing and epoxy the whole thing shut so none of that is visible, but still irks me lol.

thoughts and comments appreciated. If anyone is looking for some guidance on how to go about this themselves and whats involved, dont be afraid to ask.
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Old 01-01-2019, 11:29 PM
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Originally Posted by Slamrod View Post
Decided to slim down the board design. With lots of tedious effort of laying solder tracks and carefully rearranging components, i managed to shrink the layout down to nearly half the footprint of my previous layout. I think this is basically small as humanly possible to make this thing without using smd components.






As you can see its a very tight fit. Unless you are **** as i am about making it small (discrete) as possible, i wouldnt go through the trouble. The solder tracks on the back were very difficult because i did not have a mini vice to hold the board still, nor a soldering iron with accurate temperature control. One thing that is driving me MAD is that i did not account for the second signal wire in this design. Of course, im just going to link the second signal wire to the first one rather than solder it to the board itself, but considering how clean i made this damn thing its frustrating to have to resort to some ghetto rigged crap like that to make it happen. I suppose its a moot point since im going to stick it inside a housing and epoxy the whole thing shut so none of that is visible, but still irks me lol.

thoughts and comments appreciated. If anyone is looking for some guidance on how to go about this themselves and whats involved, dont be afraid to ask.
A lot of liquid flux and tiny iron tip will make that soldering easy.
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Old 01-02-2019, 08:11 AM
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That's great work! I've soldered SMD plenty. It's really not that bad. Even the dust-particle sized 0805 resistors. They remind me of those Hershey's chocolate singles but shrunk by Rick Moranis. If you're interested, design your project with Eagle (or similar board design program, there are free ones out there) :

https://www.autodesk.com/products/eagle/overview

Then submit your file to these guys and print it out:

https://oshpark.com/

I've used Oshpark in the past great work and great turnaround.
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Old 01-16-2019, 03:27 PM
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So according to someone who is not in the US or subject to the laws of the EPA, this thing works. No codes. However this person did mention that so far, their catalyst monitor has not completed. Not sure if it still is working on it, or as others suggested, the monitor may never complete - in any case, EPA guidelines allow you to have one incomplete monitor and still pass, so as long as your other systems are working, you WILL pass inspection.

This was using the device shown in my previous posts, as well as two (8 ohm, 25w) resistors, one for each bank/sensor. The device prevents the codes for the o2 sensor while the resistors mimic the o2 heaters, which prevents those codes and allows that monitor to complete.

So long story short, if you want to pass inspection without any secondary o2’s, this setup works!

edit; feel free to ask questions or shoot me a pm if you want more details on the setup, more than happy to help. Once again i do not condone nor take any responsibility for anyone breaking any laws lol
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Old 01-16-2019, 06:25 PM
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How much have you driven since you did the install? It shouldn't take too long for all the readiness tests to complete.

Do the 8 ohm 25 watt resistors get hot? Where did you mount the whole setup?
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Old 01-17-2019, 11:50 AM
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Originally Posted by SquidBeak View Post
How much have you driven since you did the install? It shouldn't take too long for all the readiness tests to complete.

Do the 8 ohm 25 watt resistors get hot? Where did you mount the whole setup?
i suspect the drawback with this setup is that the catalyst monitor will never complete, as all other monitors were ready except that one. In any case, no codes, and having only one incomplete monitor doesnt prevent passing inspection, so good enough.

the resistors are supposed to get hot, although i dont think they get hot enough to ignite anything. Im still able to touch them just fine, again i hear they are known to get hotter but idk, the o2 heater monitor completed so theyre working as intended. You can just wire them up and tuck them loose into the little valley between your front valve cover and the lower intake manifold, nothing down there that can get melted and its out of the way. No need to fasten them down or anything. Same thing for the sim itself, just tuck it out of the way and it should be fine. I would recomend sealing the sim up though as its all exposed electronics, also the LEDs on it are pretty bright and noticable when you pop the hood.

Last edited by Slamrod; 01-17-2019 at 11:52 AM.
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Old 01-17-2019, 11:54 PM
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Originally Posted by SquidBeak View Post
How much have you driven since you did the install? It shouldn't take too long for all the readiness tests to complete.

Do the 8 ohm 25 watt resistors get hot? Where did you mount the whole setup?
If you use the engine cover, then you can just tie up the O2 sensor on top of the valve cover (keep the tip from touching). Assuming you care about visuals...
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Old 01-26-2019, 07:05 PM
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Another quick update on this:



The catalyst monitor finally completed!
So in summary: this cheap, simple, 555 timer based o2 simulator will allow you to eliminate all secondary o2 sensor codes, as well as let ALL monitors complete - as long as you are using resistors to sim the heater elements or keep the sensors as well.
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Old 01-26-2019, 07:32 PM
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I had a feeling it would finally work. If not, I would think you'd get a CEL at some point.

Great news.

I just sent you a PM
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Old 01-26-2019, 07:42 PM
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Bravo!
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