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Discussion Starter · #1 · (Edited)
So here's the deal: No one that makes o2 sims can get the voltages to match what the computer wants to see, ive tried the one from o2sim.com and get a voltage code on both banks rear o2 sensors, the one that is hooked up to the sim. Now with the bimmerbrakes o2 sim the code also comes back several days later after I replace the old one with the bimmerbrakes one and clear it.

Im going to go find out what voltages the rear o2 sensor should be seing on a stock car and maybe Ill have one made that works properly without a check engine light. :thumbup:

What do you guys think?


My install for reference:
Cut the two yellow wires in the ecu box under the hood and installed the o2 sim directly to the ecu harness.
Using stock o2 sensor for the heating circuit.
Trial 1: o2sim.com generic dual output -> cel after 2 days, goes on and off. Voltage bounces between .7 and .4
Trial 2: bimmerbrakes.com dual output -> cel after 4-5 days comes and goes. Voltage read between .7 and .1. Not sure if that was correct so I got a replacement from [email protected]
 

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Are you sure that you're doing it right? There is nothing special about an M3. All post-cat O2s do the same job, so there shouldn't need to be much or any variance in the simulator.
 

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In order to help, we'll need more info on how you installed what you have installed.

So provide details on the parts (links) and instructions you followed, with any variations.
 

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Discussion Starter · #4 ·
In order to help, we'll need more info on how you installed what you have installed.

So provide details on the parts (links) and instructions you followed, with any variations.
I added some info. They are installed correctly, I am getting voltage readings from my laptop when scanning the car.
 

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Personally , ive never seen (in person) an o2 simulator working as it should.

People either:

A. Invest in a handheld code reader like a peake tool to clear the codes every other other other day.

or,

B. Invest in shark, ESS, or someother tune that disables/removes the o2 readiness/coding from the ECU/DME.
 

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Discussion Starter · #6 ·
^^ i know man, it sucks. im getting a tune but i want them to leave the post o2 active to pass an obd inspection we have in nj
 

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can you clear codes right up to the point they inspect it?

leave the code on til the morning or the day of, and clear it right before you arrive:p?
 

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Discussion Starter · #8 ·
can you clear codes right up to the point they inspect it?

leave the code on til the morning or the day of, and clear it right before you arrive:p?
speaking of: my boy just did that yesterday and they failed him because the rear sensors were "not ready" and they told him to come back in 2 weeks and also told him to not clear the codes :banghead:
 

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Discussion Starter · #9 ·
Bump for info

Anyone know of anyone who can make a custom voltage simulator?
 

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If it is a track car then don't worry about the light. If it is a street car well then..... You are violating a few federal laws :)
 

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Discussion Starter · #11 ·
If it is a track car then don't worry about the light. If it is a street car well then..... You are violating a few federal laws :)
Thanks for the helpful insight :rolleyes:
 

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Discussion Starter · #13 ·
So theoretically speaking if I were to have hi flow cats that are not in BMW spec but conform to USA EPA regulations how would you get the values within spec? :)
 

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So theoretically speaking if I were to have hi flow cats that are not in BMW spec but conform to USA EPA regulations how would you get the values within spec? :)
Do you actually have hi-flow cats? Flashing your DME to european specs and then actually using O2 sensors might work (btw technically if the cats aren't stock, they don't conform to US regulation... I'm sure you know that, but just saying...)
 

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Discussion Starter · #15 · (Edited)
There are aftermarket cats that get the exhaust within government specs, making them legal according to pollution requirements

Also the euro flash won't help, people with oem euro section 1 cats don't have a cel and have passed Cali smog tests with us software.
 

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There are aftermarket cats that get the exhaust within government specs, making them legal according to pollution requirements

Also the euro flash won't help, people with oem euro section 1 cats don't have a cel and have passed Cali smog tests with us software.
Sorry i was on Vacation last week. i will do some digging when i get caught back up and see what I can do
 

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There are aftermarket cats that get the exhaust within government specs, making them legal according to pollution requirements

Also the euro flash won't help, people with oem euro section 1 cats don't have a cel and have passed Cali smog tests with us software.
It might get it to within the guidelines the government sets for manufacturers, but as consumers, I'm fairly sure only factory cats (and equivalent replacements) are legal. I need to pull up the actual regulations again. Unlikely anyone would say anything as long as the emissions are within specs though.

And euro flash probably would help. The tolerances are likely to be looser than what the US DME has (US DME is designed with 400 cell cats in mind, while euro DME is designed with 200 cells in mind. The euro flash's "lower limit" is probably set lower). Since you've got all the software to flash your DME, you may as well try
 
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