02 sensor - tune question?

Superhawk2002

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I have a fault showing up as a driver side rear 02 sensor. It actually came on right after the header install. I thought that maybe the car didn't like the headers without a tune. After the tune went in, it obviously did not go away.

Is there an issue with just having the tune with 02 sensors deleted? I plan on just leaving them in for good looks. I want to keep the catted H-pipe in as well.

Hoping this is also why the car surges fairly hard around mid throttle...
 
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Are you using O2 Extensions? If so you need to remove them and pull the wiring harness down so there is nothing but original O2 sensor to the bung in the collector.

These cars do not like aftermarket catalytic converters. You should seriously consider deleting the catalytic converters and getting a tune.
 

masonh

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Is there an issue with just having the tune with 02 sensors deleted?

In Nashville, you can't just turn the rear O2 sensors off in a tune. The testing center will get "not ready" codes back and you can't pass. If that is indeed what you are asking. So it depends on where you live whether they can just turn them off or not.
 

TORQJNKY

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Are you using O2 Extensions? If so you need to remove them and pull the wiring harness down so there is nothing but original O2 sensor to the bung in the collector.

These cars do not like aftermarket catalytic converters. You should seriously consider deleting the catalytic converters and getting a tune.

Van, do you know if swapping the aftermarket cats with the stock cats is worth it? I really don't like running without cats. Too loud for my taste and the exhaust smell is terrible.
 

Superhawk2002

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I was only getting 1 code, but now 4 came up.

P0050, P0059, P0000, P0155

I am guessing from reading online that they all have to do with the 02 sensors.

There are no emission testing here, but I was hoping to keep the cats. If the easy (and possibly safer) solution is to put an offroad H-pipe in with a modified tune, then so be it. I too don't care for the exhaust sound without cats, but will do what I gotta do.
 

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Van, do you know if swapping the aftermarket cats with the stock cats is worth it? I really don't like running without cats. Too loud for my taste and the exhaust smell is terrible.

Keep the OEM. After market cats are just for emissions testing. None of them have been CARB certified to my knowledge.
 

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I had the same problem with my car, shop used O2 extensions and the car threw a fit. Got under the car and attached the 02 sensors abck to the OEM harness w/o extensions (it is a bitch and all you have to do disconnect the harness at the plastic clips to allow wiggle room). Car ran great after that and no CEL issues. Also some surging is to be expected, I assume you have a CAI and tune. Also like Van said, really recommend getting an O/R pipe, as any type of Catalytic Converter could and will eventually clog with the power these cars make, also the car wont be any louder than stock while are you cruising at any speed.
 

Willie2

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Jeff, I don't have an answer for you but it sounds like you got it figured out. Good luck!
 

Willie2

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Cool, I'm having LT's installed tomorrow. I'll have them leave out the cats that came with x-pipe and cut out the OEM cats and weld them in. Thanks.

Interested to see how this turns out. Pics in a new thread please :beer:
 

Superhawk2002

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Cool, I'm having LT's installed tomorrow. I'll have them leave out the cats that came with x-pipe and cut out the OEM cats and weld them in. Thanks.


I too am interested in how it turns out.


This weekend I am going to pull the exhaust off (sans headers) and just bore all the innards of the catalytic converter out. That will cure failed converters. I need to email Lund/Lethal to see who can shut off the rear 02 sensors for me. Hopefully that fixes the codes. Maybe they can do something about the surging as well.

I am not going to spend 500 more bux for an offroad H-pipe. If boring out the converters is a no-no for some reason, I will just cut and weld in straight pipes at home.
 

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Cool, I'm having LT's installed tomorrow. I'll have them leave out the cats that came with x-pipe and cut out the OEM cats and weld them in. Thanks.

Crap. I just saw this.

That wasn't what I meant. The OEM Cats are designed to remain in the OEM location. Even if you leave COT on they are further downstream in the exhaust system. Frankly this has never been done and I don't know what to expect or tell you.

I was trying to say that I would only run the cats for visual inspection.
 

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Myfast70

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Torqjnky, they make transition cones to go from one size tubing to another. So long as the cat material doesn't extend into the coned portion you may be able to get away with cutting that angle and welding the cone onto it.

Here's a link. This isn't the size you need but they make them in various sizes (you may have to do a bit of leg work finding them) but I know they're available.

stainless transition cone | eBay
 

TORQJNKY

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Torqjnky, they make transition cones to go from one size tubing to another. So long as the cat material doesn't extend into the coned portion you may be able to get away with cutting that angle and welding the cone onto it.

Here's a link. This isn't the size you need but they make them in various sizes (you may have to do a bit of leg work finding them) but I know they're available.

stainless transition cone | eBay

Thanks Fast70. It sounds like, from what Van says, that the OEM cats can't be relocated. Not really sure why that is because when you install long tubes with aftermarket cats, the aftermarket cats are relocated further downstream as well. I'm not done with this yet. I will run the aftermarket cats for a while until I figure out a suitable OEM replacement. I don't want to run punched out cats or no cats. Sounds terrible to me and I don't want to deal with the exhaust smell.
 

Myfast70

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Thanks Fast70. It sounds like, from what Van says, that the OEM cats can't be relocated. Not really sure why that is because when you install long tubes with aftermarket cats, the aftermarket cats are relocated further downstream as well. I'm not done with this yet. I will run the aftermarket cats for a while until I figure out a suitable OEM replacement. I don't want to run punched out cats or no cats. Sounds terrible to me and I don't want to deal with the exhaust smell.

Factory cats are placed in specific locations in order to work properly. They are typically closer to the manifolds so they heat up properly to be able to control the exhaust emissions. The further away you place them the less effective they become. If you were to relocate the stock ones I would literally butt them up to the header flanges.

The next issue that you may run into is that the o2 sensor wires may not be long enough. It seems that extensions are a big no no. I would think that if you were to properly extend the o2 sensor wires by cutting them and then soldering a minimal extension on that you'd be ok. I would be certain to use the exact same size wire and solder and heat shrink (use an OEM type heat shrink that is wax filled to keep water and moisture out) every connection. You can find the connectors for o2 sensors online so I would probably buy new ones to minimize the amount of solder joints. Be sure to use a good OE grade TXL wire and not the normal "primary wire" that you find at auto parts stores.

I've built lots of complete wiring harnesses for FAST XFI and FAST Classic systems and the parts are available but you have to do some searching. Shoot me a pm if you need a source for wire or connectors.
 

Snakebite13

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When I put my American racing long tubes on about two weeks of driving, bank 2 went lean. All I did was called for and asked for a new front o2 sensor. everything was fine after I replaced it.
 

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