Definitive answer needed on emissions and O/R H pipe

[TexasKyle]

I have read numerous threads on this..

I live in Harris County Tx, (Houston) where they will do an OBDII check of the system during the yearly car inspection. Is there anyway to run an offroad (catless) H or X pipe with LT's so that I do not have to do some swapping and hassling with a Catted setup to pass the O2 sensor test.

Is there a real way to tune around the missing O2's to where the OBD scan will come back clean?

I am gathering parts for my engine swap, and doing a lot of things at once. LT's included provided I can actually do an O/R pipe and still pass emissions.

There are catted pipes for the LT's from various brands, but to get LT's for a reasonable price, O/R is the way to go.

Comments please.

 

[remainvayne]

As long as your tune has the check engine light turned off you should pass. I live in WI and have to go through emissions testing every 2 years and both times I've gone to get tested I've had my O/R H on with stock mufflers to keep the sound down.

 

[Natural1]

Mine always passes, it's tunable.. I used to pass with MILs but it's in my tune now. As a matter of fact, my rear O2 sensors aren't even on the car.

 

[bullittrevor]

I can't pass. I live in Fort Bend county. My sticker has been expired for 8 months or so now. My check engine light won't stay off for more than half a day even when the shop messed with the tune. I've had enough of all the bs trying to pass and I don't feel like having to find a shop every year I can bribe to pass me. Im switching to a catted h-pipe.

 

[bigray327]

Y'all are wrong about the tune. The state computer scanner machine will know your O2s and EVAP are not reading ready, and will fail you out. If you want to keep one pipe on all the time, the only solution is to use spark plug non-foulers on the rear O2s to pull the sensor out of the exhaust stream enough to make them think there are cats. You'll still get the EVAP showing not ready, but you can pass with one NOT READY flag.

Good how-to here: link. I believe our O2 sensors use 18mm threads.

Doug (KemahGT here) did the non-fouler thing and claims to have passed. He double stacked two on each rear O2, which involves drilling out one. Of course, you also need to find a clueless inspection shop that either won't visually inspect under your car, or won't know what a catalytic converter (or lack thereof) looks like. I swap pipes with a catted midpipe, but I think I'll try this next time around.

Also Kyle, utilize the free rental OBD scanners at Auto Zone. You can drive around with the scanner connected and see whether your various emissions components (O2s, catalyst, evap, etc) are reading READY. Very helpful, when you're driving the cycle and such.

 

[rojizostang]

you should pm texasblownv8. i think he can help you. probably not a good idea to give up all the "secrets" publicly though.

 

[Fullboogie]

Bigray is correct - there is NO WAY to "tune" the computer to ignore the rear O2's and report "ready" during the inspection.

 

[TexasBlownV8]

This applies to those of us who have no choice but to be able to pass OBDII emissions testing with not more that 1 or 2 "Not Readys". In certain areas of Texas now, we are allowed only 1 not ready on the S197's (based on year models, and all S197s fall into that).

Unless a tuner has found a way to make the catalyst tests "not available" or "fix it" in the tune, you have no choice but to either use some catted setup or provide some simulated signals for the rear O2 sensors. From the PCM perspective, there's not too much expected from rear O2 signals, but the signals are expected to be somewhat close to sync in relation to the varying front O2 signals. Using foulers and/or a special circuit, you should be able to simulate the needed signal w/o actually having cats, as long as the rear sensors are still in the system downstream somewhere. In a gutted cat is a nice place for one, since it 'passes' any kind of quick visual, which may or may not be done.

Just to reiterate a basic point, when you get a performance tune, it's very common for a tuner to turn off the rear O2 sensors, unless you tell them otherwise. This in itself will cause you to fail with up to 3 Not Readys. ANY CEL is an automatic failure as well.

If you aren't sure if your rear sensors are on or off, simply attempt to datalog the rear sensors (sensor #2 in banks 1 and 2). If you get signals, they are on. If there is no PID or no signal, they are off.


In a few months I will be doing more "testing" on a cat-less solution, after I pass inspection myself . I'm currently using high-flow cats and have rear sensors that do come up as ready (enabled in the tune of course).


Tanner, I'd like to know more about your tune; are you in one of the OBDII counties? Reply off-line if you'd like.

 

[TexasKyle]

Thanks for all the replies. Majority seems to say what I thought, that you can't turn the O2s off, AND make the PCM see a false input for them or give a false "ready".

Tanner, I would like to hear more from you on this, either here or PM.

Thanks y'all

 

[bmaxwell]

I just go to a town where they don't do emmissions testing lol the smaller Texas towns don't do emmissions. I have friends in small towns I'll just go hang out with, it kinda gives me an excuse to go visit but I understand it's a PITA that way! Although I did pass with an offroad x in Houston when I used to live there because I had a friend who owned a shop and had a mustang like ours and I think he somehow used his car to pass mine. He got me my sticker and told me not to worry about it haha WIN

 

[BadHabit2Break]

Can you use some rear 02 sims?

I ran these on my Camaro Z28 with LT's. Seemed to work fine for me with my tune. I also had the O/R Y-pipe with the options of adding high flow cats.

And there is a little more involved than just making the CEL light off. They do hook it up to a computer.

 

[remainvayne]

Can you use some rear 02 sims?

I ran these on my Camaro Z28 with LT's. Seemed to work fine for me with my tune. I also had the O/R Y-pipe with the options of adding high flow cats.

And there is a little more involved than just making the CEL light off. They do hook it up to a computer.

If I remember correctly, I think the government or someone made MIL eliminators illegal so you technically shouldn't be able to purchase them anymore.

 

[james05gt]

Just hope they don't do a visual! When I got my car inspected one of the guys doing the inspection had a pole with a freaking mirror! and was checking underneath the car, at the time I had my stock h with cats so I passed. But now I got an o/r h so 2yrs of fun fun. I might fab something that resembles a cat or switch to the stock one the next inspection.

 

[05bluestang]

You can still get the MIL's
http://www.americanmuscle.com/stmilel.html?gclid=CLC0m_KdkqcCFQFM5QoddjqycQ

 

[bigray327]

You can still get the MIL's
http://www.americanmuscle.com/stmilel.html?gclid=CLC0m_KdkqcCFQFM5QoddjqycQ

Those won't eliminate the NOT READY flags you get, though.

 

[BadHabit2Break]

sounds like someone should come up with an O/R pipe that you can put s cats on for inspection and then go home and remove them and put a staright pipe in its place.

 

[remainvayne]

I run a BAMA tune from 2006 and have used that tune twice for inspections. I didn't ask him to do anything different from my tune because I have to pass emissions and I'm almost positive my rear O2's are switched off. The last time I went for emissions testing, April of 2010, I didn't get a single 'not ready' flag.

I know exactly what you're talking about Bigray, my dad's 4Runner got a 'not ready' flag because his gas cap was leaking. However, I'm not saying everyone will experience the luck that I have concerning emissions...

 

[bigray327]

sounds like someone should come up with an O/R pipe that you can put s cats on for inspection and then go home and remove them and put a staright pipe in its place.

It's pretty easy to flange in some cats, but I chose to just buy a catted midpipe that I swap in every year. It takes about 15 minutes, mainly because the damn driveshaft loop needs to be removed. Drive the "cycle," get inspected, throw the awesome midpipe back on for 364 more days.

I am gonna try the non-fouler thing, though, just for kicks.

 

[Fullboogie]

Bassani already has a catted X pipe with removable cats, and a section of pipe that replaces the cats for "off road" use.

http://www.lightningforceperformanc...es_w/Cats_2005-10_Mustang_GT_-_Stainless.html

Ray, you are correct again with the codes. You will not only get a code for each rear O2 being non-responsive, you will also get a code for the O2 heater circuit being not ready - for a total of 3. I've been through this three years in a row with multiple hacked-up tunes that claim to be able to pass emissions, and they never work. I have to put my car on my buddy's lift and swap the damn H pipe out every year for testing.

I too am very interested in how Tanner is passing emissions with no cats and an emissions computer hooked up to the OBDII port...

 

[king_ahmet]

I built my own...

sorry one is sideways...