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Emissions Issues: O2 Sensor and O2 Sensor Heater Monitor Will Not Ready Up

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Hey folks,
2013 Mustang GT here. I've been fighting passing emissions for the last year or so. I'm in Arizona, so emissions regulations are relaxed here, but only 1 system in the monitor readiness check is allowed to be "not ready" by Arizona law. My car has an issue getting O2 sensor and O2 heater sensor monitors (2 seperate monitors) to ready up. The catalyst monitor does ready up eventually although it takes about 5-10 drive cycles after resetting the readiness monitors every time. Here's what I've concluded:

I have Kooks longtube headers, Kooks catted H-pipe midpipe, and a Lund tune. With no O2 spacers / defouler trick on the O2 sensors, the car pulls a CEL for too much emissions from the high flow cats (I believe P0420 and P0430) BUT both the O2 sensor and O2 heater sensor monitors read as "ready". With O2 spacers / defouler trick on O2 sensors, no CELs appear but the O2 sensor and O2 heater sensor monitors stay in the "not ready" position. I imagine this is due to them not getting hot enough being that the O2 sensors are too far away from the midpipe to get hot enough from exhaust. This also tells me the issue is not tune related as both monitors read "ready" when there are no O2 spacers installed.

I'm at a dead end here not knowing what to do. I'm not able to install the stock exhaust as I do not have it and a stock midpipe does not fit on Kooks LTHs. I could purchase Kooks Green catted midpipe (has extra restrictive cats) but I would really rather not spend $2500 on an exhaust pipe just to pass emissions. I would ideally like to find a fix for this issue that works, including not triggering a CEL and having all monitors as ready. Does anyone have any ideas for me? Open to anything.

Thanks everyone!
 
I haven't gotten my car inspected since I put long tubes on, but before that I had a hell of time getting those two monitors to run. I had a flowmaster cat back exhaust on the car at the time and I tried everything to no avail. I switched out the exhaust for a quieter setup and the monitors ran before I was off my block on the test drive. I hated the flowmaster noise anyway :)

Would your exhaust setup let you put the stock mufflers back on? SOmething to add backpressure/restriction? You are obviously on the right track with your idea.

DaveW
 
My exhaust combo is smog legal and I still have to put the stock midpipe back on to get those sensors to ready up.
Just a Magnaflow X-pipe and Ford Racing axle back. I drove around for a long time before swapping back. The sensors were ready after only one or two drives.
 
I haven't gotten my car inspected since I put long tubes on, but before that I had a hell of time getting those two monitors to run. I had a flowmaster cat back exhaust on the car at the time and I tried everything to no avail. I switched out the exhaust for a quieter setup and the monitors ran before I was off my block on the test drive. I hated the flowmaster noise anyway :)

Would your exhaust setup let you put the stock mufflers back on? SOmething to add backpressure/restriction? You are obviously on the right track with your idea.

DaveW
Unfortunately, my current exhaust system won't let me swap anything out to solve this problem other than Kooks $2,500 green cats midpipe (which I have not purchased... yet). Unless there is another green cats midpipe available from a different company that I do not currently know about that would fit on Kooks LTHs, which I'd love to hear about!
 
My exhaust combo is smog legal and I still have to put the stock midpipe back on to get those sensors to ready up.
Just a Magnaflow X-pipe and Ford Racing axle back. I drove around for a long time before swapping back. The sensors were ready after only one or two drives.
I really wish I had the ability to throw the stock midpipe back on without swapping the headers on the car.
 

Dave_W

Cones - not just for ice cream
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From the anecdotes above, it sounds like increasing the exhaust backpressure could help "ready" the sensors. For a low-buck hack, you might try using some coarse steel wool or metal potscrubbers over the ends of the tailpipes and drive around a bit. Use some baling wire or similar to keep it from falling off. You don't want to clog the exhaust too much, just make it a bit less free-flowing.
 

ArizonaBOSS

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A bit roundabout, but do you know anyone in Tucson or Yavapai County up North that would let you register in their non-emissions county?
 
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You can do what I did, I registered it with Haggarty as a custom car with their insurance and was able to bypass all the emissions tests since the car is now exempt in Arizona and registered as a classic/show car.
 
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How about getting a couple universal fit cats from Summit or Amazon and have a custom exhaust shop weld up temporary mid-pipes or maybe an x-pipe with the cats to pass emissions?
 
From the anecdotes above, it sounds like increasing the exhaust backpressure could help "ready" the sensors. For a low-buck hack, you might try using some coarse steel wool or metal potscrubbers over the ends of the tailpipes and drive around a bit. Use some baling wire or similar to keep it from falling off. You don't want to clog the exhaust too much, just make it a bit less free-flowing.
Not a bad idea. I'll think about this a bit more, I wonder if loading all the way at the end of the mufflers would get to the O2 sensors... or if I would have to load it just after the O2 sensors. I saw on another forum one of the S197 guys welded on a circular plate right after the O2 sensors to heat them up more, but I don't have the access to a flange right after the O2 sensors. My next exhaust connection flange is at the end of the H-pipe I believe.
 
A bit roundabout, but do you know anyone in Tucson or Yavapai County up North that would let you register in their non-emissions county?
This is a fantastic idea and I reached around to a few friends but unfortunately no such luck. It was something I was thinking about early on since it's such an easy route. I'm also wondering why / how every 11-14 S197 owner with LTHs is not having this issue... do some LTH brands not have this issue or find a way to work around it...
 
You can do what I did, I registered it with Haggarty as a custom car with their insurance and was able to bypass all the emissions tests since the car is now exempt in Arizona and registered as a classic/show car.
I did end up doing this. Unfortunately, I'm paying an astronomical amount for insurance between the Mustang and my daily driver so if a solution for this issue presents itself to pass emissions with all readiness monitors, I'd be over the moon still.
 
How about getting a couple universal fit cats from Summit or Amazon and have a custom exhaust shop weld up temporary mid-pipes or maybe an x-pipe with the cats to pass emissions?
The O2 sensors on this midpipe are directly after the midpipe cats so there isn't any room to install another cats before the rear O2 sensors on this setup unfortunately. Great idea though, had me thinking!
 
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The O2 sensors on this midpipe are directly after the midpipe cats so there isn't any room to install another cats before the rear O2 sensors on this setup unfortunately. Great idea though, had me thinking!
I'm talking about temporarily removing your Kooks mid-pipe with its hi-flow cats (and their excessive emissions), and temporarily replacing it with a custom mid-pipe or pipes that has/have standard, restrictive, low emission cats welded in so you can pass emissions.
 
I'm talking about temporarily removing your Kooks mid-pipe with its hi-flow cats (and their excessive emissions), and temporarily replacing it with a custom mid-pipe or pipes that has/have standard, restrictive, low emission cats welded in so you can pass emissions.
That's not a bad idea. It would likely cost me significantly less than the $2500 midpipe that Kooks want for their "Green" catted midpipe. I'll look into a setup like this. Thanks!
 
What about wrapping the h including the cat so everything holds more heat. Maybe even add something under the wrap just past the rear O2 for thermal mass - couple small sections of exhaust pipe split and clamshelled - anything with good contact. I'd be curious what the temps are from the headers through the end of the h pipe. Might give you a baseline. Borrow a IR thermometer?
 
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Denver, NC
I have the same problem as the OP. Kooks headers and green cats and the damn sensors won't ready up. I've driven over 100 miles with no joy.

My tuner claims he can't alter anything on emissions, so I am stuck with inspection due within 9 days.

02 sensor, Catalyst, 02 heater sensor.

Help!
 
I have the same problem as the OP. Kooks headers and green cats and the damn sensors won't ready up. I've driven over 100 miles with no joy.

My tuner claims he can't alter anything on emissions, so I am stuck with inspection due within 9 days.

02 sensor, Catalyst, 02 heater sensor.

Help!
It might be one side giving you greif. Are you running extensions on the O2s? I kept throwing codes until I removed the extension that I found on my car. Had to reach way back behind the engine and release the loom . Tied a string to the passenger side connector, pushed the passenger side connection up over the gear box to the driver's side wrapped really good with heat resistant tape, pulled it back over the gear box and had just enough to connect the O2.

I'm only running fronts and am able to exempt emissions by keeping it below 5000 miles per year. Wonder if there's a loophole in your area.
 

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