OBD readiness - oxygen sensors incomplete

370z_stillen

Hi everybody,

I am having some problems with completing OBD readiness. In The Netherlands we are obliged to have a complete OBD readiness or else we are not allowed on the roads. My car is incomplete on 1 section, which is the 'o2 sensor monitor'.

I just have Ecutek installed on my car and I think there might be the problem. If I dig deeper in the OBD oxygen sensor, I see:

- bank 1 sensor 1: not complete
- bank 1 sensor 2: complete/passed
- bank 2 sensor 1: not complete
- bank 2 sensor 2: complete/passed

So the problem seems to be in both sensor 1's. My tuner says the oxygen sensor are working and is currently checking at Ecutek, but do others know this problem as well? I have empty cats by the way but that shouldn't be the issue as far as I know.

SonicVQ

When the catalytic converts are removed (or emptied) tuners often turn off certain
OBD monitors and/or disable codes. This prevents a check engine light.

However, that same action prevents the OBD monitor from running, so it will NEVER be "completed"

If the tuner turns everything back on, it is likely the O2 monitor will run and complete, but the catalyst monitor will fail. Maybe "O2 defoulers" would help, but the 2012+ OBD systems seems to be able to detect them.

I may be wrong, but unless you "know a guy" I don't see how you could pass an emissions test without a cat and a factory tune.

370z_stillen

Thank you for your respons. I hope I can overwrite with a temp tune to activate the monitors again and we will see what happens. But… the car has no catalyst sensor right? Atleast not in the obd. So I assume this wont be an issue and is not part of OBD readiness. Correct me if I am wrong.

Does anybody know for sure what sensor 1 is and what is sensor 2? I thought sensor 1 was just an AFR sensor. Cant seem to find the right answer anywhere.

SonicVQ

Sensor 1 is the wide band, air/fuel sensor before the cat, aka pre-cat sensor.
Sensor 2 is the narrow band O2 sensor that is after the cat, aka post-cat.

The catalyst test for efficiency compares the air/fuel values to the O2 sensor values.
A healthy cat has the ability to store oxygen, so the sensor 2 lean to rich or rich to lean switching time is slower than the sensor 1 change from lean to rich or rich to lean.

In your case, the rich/lean and lean/rich signals of sensor 1 will be similar that of sensor 2. This means the catalyst is not operating at the required level and a P0420/P0430 is triggered.

I am not aware of any tune that can get a monitor to run and pass. As far as I know, the only way to get the monitor to run is to do the required "drive cycle"... and then it will only "complete" or pass if the test criteria is met.

I can't see that happening without a cat.

What did you do other years to pass emissions?

370z_stillen

Thanks again for your detailed reply. Hope not but I think you are right. I only have the car 1 year now. When I bought it, it got clearance but my guess is they took another route. There is an alternative (atleast in the Netherlands) to get clearance if OBD readiness is not an option, and that is an exhaust test. But in my case, too many adjustments, new tune, more hp and the result is a too high number. So not an option. I will check but I think you are right and I need new cats…

2011 Nismo#91

O2 Simulator Mini Cat Cel Fix stainless steel Rear O2 sensor simulator.

Its a mini cat on the o2 sensor. I use them and it worked for me.

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370z_stillen

Will definitely look into that. Thanks!

Jhill

Like posters said before your tuner likely turned it off because of the cats. I’m a little confused by this though as the rear 02 ran and passed and those are the ones that would/should likely fail without cats. The rear o2’s with a good cat should have slow low amplitude switching voltage and hover around 1/2 a volt, without the cats it should be switching rapidly between about .1-.9 volts. You can make sure the fronts and enabled and then runs the extend j bend bungs for the rear o2’s if you don’t have to pass a visual. This will give you full functionality of the fronts and dilute the exhaust that the rear 02’s see.

370z_stillen

Thanks for your reply. The rear o2 sensors give a 'good reading' because the front are disabled, so the rears are the first to receive the readings. If the tuner enables the front as well, the reading at the front will be the same as the rear and then the rear o2 will likely fail. I am thinking about adding the mini cats of go back to HFCs instead of empty cats, some more research to do first!

370z_stillen

Sorry guys still a bit confused. We are currently checking with Ecutek what might be the problem, but my tuner stated that sensor 1 IS enabled, or else he would not be able to read AFRs through OBD. So somehow, sensor 1 seems activated, there might be something in the Ecutek tune preventing from going to complete OBD readiness. Anyone a clue?

SouthArk370Z

If you have empty cats (I'm assuming that means no catalyst in the can), the car will not go to the ready state if everything else is in stock condition.

Most (if not all) modifications (eg, O2 sensor extenders) will fail a visual check.

The only sure solution I know of is to use an OEM-spec cat for a while, until the system shows ready, and you get the inspection. What you do after you pass inspection is up to you.

Edit: You may also need to tweak your tune to get the emissions numbers right.

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