ARH Long Tube Headers w/o Cats...

[Ludville1]

I have stainless steel American Racing Headers w/ stainless steel y pipe w/o cats. I get codes PO 420 and PO 430 (catalyst system below efficiency bank 1 & 2). I can reset the codes through the tuner, but after a short time, they come back on. Would changing the 02 sensors cure this problem, or is there another cure...seeing are there are no cats?

 

[Tim Garceau]

Could try spacers or "defoulers" but you might need to double them up.

Depending on your tuning device, a custom tune will just eliminate secondary O2 activity.

 

[Fast69Mopar]

Could try spacers or "defoulers" but you might need to double them up.

Depending on your tuning device, a custom tune will just eliminate secondary O2 activity.

Without the catalytic converters in place the PCM is looking at the Downstream oxygen sensors and seeing a rich condition. The PCM uses the Downstream oxygen sensors to monitor catalytic converter performance and to adjust the long term fuel trim.

Like the other post said you can try a spark plug non-fouler. You will probably have to drill the holes in the non-fouler for the tip of the oxygen sensors to fit inside it.

If you want to not have to worry about it ever again, get one of the custom tuners to eliminate them from the tune.

The non-fouler route will only cost you about $10.00 from the local auto parts store and a few minutes with a drill.

If you can use your tuner to monitor the Downstream oxygen sensors, record the voltage before and after the installation of the non-foulers to see they will bring the sensor voltage down enough to stop the PCM from setting a DTC and pass the OBD monitor.

 

[Pull Ya]

If you have a Hemifever tune, call Sean and ask him what steps you need to take. He may be able to adjust your custom tune.
Jay

 

[Dan98]

I have heard about o2 sensor with a small amount of cat material in the No Fowler.

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[Wild one]

I have heard about o2 sensor with a small amount of cat material in the No Fowler.

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Stainless steel wool in the non foulers is the common trick.I've even seen guys stack 2 non-foulers ,but I've never tried either trick myself,always just turned the back 02's off in the tune

 

[jvbuttex]

He may be able to adjust your custom tune.
Jay

 

[Dan98]

Tune is the best way. I tried two non foulers it doesn't really work well because of the temperature reading. If o2 sensor isn't close to the stream and fluctuating constantly changing it goes to closed loop and that is 100 times ****tier than converters.

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[James OBrien]

Yep, what he said ^^^^. It'll mess with your fuel maps/closed loop and won't run as effectively/efficiently.