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Discussion Starter #1
Id like to get rid of the catalytic convertors on my 95 4.6 and run true duals. Since we have no emission laws here in Montana , I was thinking that I might get away with cutting the cats off and replacing them with straight pipe then using a set of 02 simulators to keep the computer happy.
I have already gutted the 3rd cat and put straight pipe in place of the resonator years ago and now suspecting the cats are clogging and the stock 02's are deffinately in need of replacement so if this will work out I will save myself a few hundred dollars.

Will this work on these cars and if so where can I find the correct 02 sims?
 

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MIL Eliminators go on the rear..Not the front O2 Sensor Plugs..

Anyways your plan sounds doable..

Here's a link to buy the MIL Eliminators-->>MIL Eliminators

Here's another link if you decide to just make your own-->>DIY MIL Eliminators

:)



Rayo..
 

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front 02 sensors i would recommend changing but the computer uses them for fuel trims, as rayo pointed out, the eliminators go on the rear o2 sensors. still need the front ones. however, i have a 95 lx with a catless true dual exhaust and i've never got a CEL from it. I don't have a tune either.

case in point, go get them true duals, cel or not you'll love them! make certain though you or your exhaust shop remembers an H/X pipe or dual in/dual out resonator in the center or it will sound terrible. when I set up my true duals I completely forget that very important part of the puzzle and it took me until i did an oil change to figure out why my exhaust sounded so terrible. This is also why I no longer drink beer while I'm welding up an exhaust :)
Travis
 

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Discussion Starter #4 (Edited)
So these MIL Eliminators just keep the CEL light from tripping after removing the rear 02 sensors? And going catless but replacing the front 02's will be okay with the computer?
 

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So these MIL Eliminators just keep the CEL light from tripping after removing the rear 02 sensors? And going catless but replacing the front 02's will be okay with the computer?
That's the way it's supposed to work.. :rolleyes:

The MIL Eliminators make the computer think you still have cats..Definitely keep the front O2 sensors..Those are important..



Rayo..
 

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Discussion Starter #6
So I can remove all the cats, put a pair of new 02's up front, remove the rear 02's without any MIL Eliminators then finish with any exhaust setup I want and the computer wont be effected by this aside from throwing a CEL light? Or are the MIL's necessary for the car to run properly?
 

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Should be no CEL light, that is what the MIL eliminators are for.

Al
 

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So I can remove all the cats, put a pair of new 02's up front, remove the rear 02's without any MIL Eliminators then finish with any exhaust setup I want and the computer wont be effected by this aside from throwing a CEL light? Or are the MIL's necessary for the car to run properly?
If you get proper MIL's then the light will stay off.

But I think your real question is if you just leave the rear ones unplugged and the CEL light stays on - will it effect anything else.

No, it won't effect the running of the car with the exception of that irritating light and the corresponding code being stored in the ECM (rear catalyst efficiency below threshold).
 

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Discussion Starter #9
If you get proper MIL's then the light will stay off.

But I think you're real question is if you just leave the rear ones unplugged and the CEL light stays on - will it effect anything else.

No, it won't effect the running of the car with the exception of that irritating light and the corresponding code being stored in the ECM (rear catalyst efficiency below threshold).
Netkeym you're correct. I dont even know that the bulb works anyway and I have an obd2 scanner so I can check it periodically. Thanks for the information guys:cool:
 

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Netkeym you're correct. I dont even know that the bulb works anyway and I have an obd2 scanner so I can check it periodically. Thanks for the information guys:cool:
The Check engine light will turn on when you put your key into the Run position and turn off after you start it. But yeah .. removing your cats and leaving the rear o2's MAY set a check engine light .. depends on your driving style, conditions to run the catalyst efficiency monitor. The MIL eliminators will work - what the computer is looking for is a lower profile signal than what it recieves from the front o2's ( you need these for fuel trim ) on the rear o2's, Fords have a pretty high threshold for what they consider a "bad catalyst", thats why it has not set on certain vehicles. I have also heard about usng a spark plug non-fouler between the o2 sensor and the bung hole. :tongue: Pulling the sensor slightly away from the exhaust flow will reduce a voltage change and create a similar waveform to a normal cat equipped vehicle.

If you think your cats are clogged .. you can put a pressure gauge in the front o2 sensor location and see how much back pressure you are running at - typical is very low, 1-2 psi .. any more than that and I would consider an exhaust restriction of some type. Although they usually dont go bad unless you had something that may cause damage to the catalyst such as over-fueling - bad PCM for example. What makes you suspect bad cats anyways ?
 

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I have also heard about usng a spark plug non-fouler between the o2 sensor and the bung hole. :tongue: Pulling the sensor slightly away from the exhaust flow will reduce a voltage change and create a similar waveform to a normal cat equipped vehicle.

If you think your cats are clogged .. you can put a pressure gauge in the front o2 sensor location and see how much back pressure you are running at - typical is very low, 1-2 psi .. any more than that and I would consider an exhaust restriction of some type. Although they usually dont go bad unless you had something that may cause damage to the catalyst such as over-fueling - bad PCM for example. What makes you suspect bad cats anyways ?
The 18mm non fouler trick works great! I agree most people think they have clogged cats because they think they don't have the power they used to. Pressure test is the best way to make sure. On my 94, I had no cats and didn't even bother installing the rear o2s. I didn't even install bungs for them, lol. The chip took care of the mil
For me. Removing cats can make a cars exhaust look more smokey and smell more raw.
 

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Hereabouts emissions now fails cars with the rear O2s shut off in the tune. There's not much choice now but to run cats or trick the PCM.

I noticed the same smokey/smelly effects Rob. My hair and clothes smell like exhaust for the day whenever I pull into the garage and exit the car immediately, I usually wait a minute after I shut off the engine to avoid it. The DOHC swap will be getting cats in the process because of it.
 

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The 18mm non fouler trick works great! I agree most people think they have clogged cats because they think they don't have the power they used to. Pressure test is the best way to make sure. On my 94, I had no cats and didn't even bother installing the rear o2s. I didn't even install bungs for them, lol. The chip took care of the mil
For me. Removing cats can make a cars exhaust look more smokey and smell more raw.
I may use the non fouler on a 1996 Chevy Tahoe I picked up, has a P0430 code and it will pass emissions on the sniffer test, but the code still comes up. Hopefully it does the trick. :D
 
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