The Computer, Emissions and Tunes.

[SixtySix]

Has anyone encountered issues with getting their cars emission tested with the rear O2's shut off?

Here in AZ, 96 + vehicles only get an ODBII test that looks for errors. There's no visual test. Just the OBDII and a gas cap pressure test. So theoretically I could run catless and as long the OBDII system checks out ok, I'd be golden.

I have a few years to worry about this, as I'm not due for an emissions test until 2011, but it's something that's been niggling at the back of my mind for awhile.

Does disabling the rear O2's show up in a OBDII scan? If so how would one get around it? Mil Eliminators?

Any theories?

 

[PenguinGT]

subscribing to see the feedback on this.

I'm in the Nazi-state (NJ), so I have a vested interested as well...

 

[jbailer]

You do not get codes having the rear O2 sensors disabled. -Joe

 

[SixtySix]

Need to convince me a little more... I realize it doesn't throw codes, BUT on my other 96+ vehicle, the printout I get makes me think the scan looks for 2 sets of O2 sensors.

 

[tmcolegr]

Here is what I read in another tuning forum on this issue.

Some emissions scans look for both sets of O2 sensors to be ready/enabled. Even with the rear O2 sensors turned off in the tune, depending what type of scanner is used, the error message will come up saying rear O2 sensors not ready and it will fail the emissions test even though there is no CEL or DTCs.

 

[SVTsupremecy]

Ya, i used to do state inspections and i help manage a carwash here in texas...if you dont have a check engine light your good. Although they are probably supposed to look under the car, 90% of State inspectors dont. Also even if you did have a check engine light on, if the State inspector is smart enough, he can run it on a ASM dyno(96 and older cars) and it should pass. Ive seen a brand new c6 z06 with full exhaust and hi flow cats pass on the ASM. Go to a nice respectable State inspection place and ask them to run a Test inspection...they can run a inspection in training mode and see if you would pass before you pay $$, if a customer asks at my work ill do it for them.

 

[SVTsupremecy]

Here is what I read in another tuning forum on this issue.

Some emissions scans look for both sets of O2 sensors to be ready/enabled. Even with the rear O2 sensors turned off in the tune, depending what type of scanner is used, the error message will come up saying rear O2 sensors not ready and it will fail the emissions test even though there is no CEL or DTCs.

Here in texas...even if it fails in 02 sensor or Catalytic converter categories, it will still pass. If you have 2 or more categories fail in Emissions portion, it will fail. Either way, take it and find a place that will run it in training mode for free to see if you will pass, tip the inspector tho, they usually get paid by the car and are doing you a favor.

 

[SixtySix]

Would MIL eliminators solve the problem? I'd sure hate to have to resort to installing the stock exhaust system... not an easy feat when you have longtubes!

 

[tmcolegr]

Would MIL eliminators solve the problem? I'd sure hate to have to resort to installing the stock exhaust system... not an easy feat when you have longtubes!

Not really sure.

My tune has the rear O2 sensors turned off but I still have the rear O2 sensors installed in the X-Pipe and hooked up to the harness. I did this so that in the event emissions testing comes to Florida, my tuner could make me an "emissions test only tune" with the rear O2 sensors enabled and I could pass.

 

[Bingo]

There's no visual test.

Do you have inspections in AZ? If so, they will probably look under the car...

 

[SixtySix]

Do you have inspections in AZ? If so, they will probably look under the car...

No, we do not have inspections like other states do. In fact our emissions testing is run by the state at official inspection stations, Not at private garages/repair facilities like other states.

On 96 and newer cars they absolutely 100% don't do anything but plug in the OBDII and pressure test the gas cap. They don't do a mirror inspection, or open the hood at any time.

I think that's what is so frustrating about this, is that every state is different!

 

[SixtySix]

Not really sure.

My tune has the rear O2 sensors turned off but I still have the rear O2 sensors installed in the X-Pipe and hooked up to the harness. I did this so that in the event emissions testing comes to Florida, my tuner could make me an "emissions test only tune" with the rear O2 sensors enabled and I could pass.

I may have to resort to doing something like that. It's a little tougher with longtubes though. The cats (I do have cats right now) are so far back, that it will be a pretty long extension to hook them up, not to mention the tuning required to compensate for the slow lightoff.

 

[Hawgman]

Here in texas...

"Here in Texas" is a VERY vague statement. It depends on what county you are in as to how "in depth" the inspection is and what all they will look for. Something as simple as a "Not Ready" code will cause a vehicle to fail in some places.

 

[Bingo]

No, we do not have inspections like other states do. In fact our emissions testing is run by the state at official inspection stations, Not at private garages/repair facilities like other states.

On 96 and newer cars they absolutely 100% don't do anything but plug in the OBDII and pressure test the gas cap. They don't do a mirror inspection, or open the hood at any time.

I think that's what is so frustrating about this, is that every state is different!

Hell, like Hawg said, regulations can vary within the state...I know that certain counties in PA don't even perform emissions tests. It's whacky, and it's most definitely a case-by-case situation.

 

[jbailer]

I had MIL Eliminators in my lat car and they worked great. The way they work is they take whatever voltage level they receive and convert it to a signal that is in the "good" range to the PCM. That way the O2 sensors are still enbled but the PCM doesn't know if the levels are out of range. You don't need to worry about this effecting how the car runs either. The rear O2 sensor's job is to simply measure catalyst efficiency. It will tell you if the emissions are too rich but is not at all involved in the feedback loop like the front A/F sensors are in closed loop mode. I haven't tried using these on this car yet. -Joe

 

[94tbird]

NYS i passed with KB's stock tune and no Rear O2 sensors. Not only were they turned off, they werent on the car haha

 

[ZmanM3]

I wanted to keep my rear O2 sensors so I just went with mIL eliminators and left them turned on. Works just fine.

 

[SixtySix]

Where did you get the Mil eliminators? I'm finding that they're hard to find for these cars. Or am I just not looking in the right place?

 

[GIG4FUN]

Where did you get the Mil eliminators? I'm finding that they're hard to find for these cars. Or am I just not looking in the right place?

I have a set that i bought from RPM Outlet way back when I bought my first GT. I never have used them (still in original package). They were listed for an '04 Mustang BUT they told me they would fit. (not for sale). I'm curious now if they do... (good question!)

 

[ZmanM3]

Where did you get the Mil eliminators? I'm finding that they're hard to find for these cars. Or am I just not looking in the right place?

I got mine on the Steeda website.