I have an LC-1 wideband (that is capable of emulating narrow band signal, but isn't quite as precise if I understand correctly...)

I have headers & then a downpipe without a cat.

Do I leave my factory O2 sensor in the front bung & install the wideband in the rear bung? (if I go this route, is there a way to disable the rear O2 sensor in the PCM, or do I just remove the error reporting codes / service engine code from the 2nd sensor)

The other option, would be welding another bung in place for the wideband & leaving the rear factory O2 sensor in place. There would still be the issue of the 2nd O2 sensor not having a cat in front of it.

Any recommendations???

 

As far as the O2 sensor after the CAT issue. There is an item out called an O2 Emulator. ZZP sells them. I have 2 that I'm going to sell. Look below for a description of the item. might solve your problem with that issue... They want $50 for theirs Selling mine for $30 shipped, new in package still. Bought from them ZZP a few months back.

Click on link: Easy Performance - O2 Emulator #EP-O2SM-GM01

OBDII cars have two oxygen sensors to measure the amount of oxygen contained in the exhaust gas. The first sensor is located on the manifold or header and measures O2 content of the exhaust as it escapes from the cylinders. This sensor is used by the PCM to calculate fuel trims and look for combustion problems.

The second oxygen sensor is located after the catalytic converter and is used only to detect the performance of the converter. The PCM does NOT use any data from the secondary O2 sensor for engine management. The PCM will set an SES (service engine soon) light (for P0140, P0141 and/or P0420) if the catalytic converter is removed, the sensor is removed, or the sensor goes bad.

The Easy Performance O2 emulator is a plug-in replacement for the secondary O2 sensor that will provide the PCM with a signal that emulates a healthy cat. An extremely compact circuit board is molded into the end of the connector to provide the most compact and water resistant simulator on the market.

Installs in less than 10 minutes and does not require any tools. The EP O2 emulator is standalone and as such does not need to be located anywhere near the exhaust system.

 

I run a ZZP Downpipe with no catalytic convertor and the O2 bung deleted completely. Downpipe connects to a Pacesetter exhaust with no resonator.

I use the Easy Performance O2 Emulator on the second O2 Sensor connection. I don't throw any codes. I swear by these little things. One thing though, I have had them fail after about 2 yrs. (I've ran them on my other GM vehicles). Not bad to replace though for the price they ask, especially what Zippy wants for them.

 

Wideband goes in the first o2 sensor area. That sensor has signals to read air/fuel ratio and talk to the PCM, and that is what you want.

 

From other message boards, most were saying to install in the front bung; (however the reason for this is that you must be in front of the Cat converter) Being I don't have a cat, I would think the second bung which is probably 20" further down the exhaust would work for my wideband. People that replaced the front O2 sensor generally had to program a narrow band signal to the PCM / ECM to keep it happy & be able to control fuel.

If I leave my front where it is, the PCM should be happy & I have heard the OEM O2 does a slightly better job at narrow band.

Thank you Zippy02 for That is precisely what I needed to know. My wideband can be independent of the PCM and I'll just remove the codes with my HP Tuner. Thanks guys!

 

In 2005 the 2nd o2 sensor read more parameters than just the cat.

 

Here are the Engine error codes that I have modified, unchecked SES enable and set to no error reported:

P036 HO2S Heater Control Circuit Bank 1 Sensor 2
P0137 HO2S Circuit Low Voltage Bank 1 Sensor 2
P0138 HO2S Circuit High Voltage Bank 1 Sensor 2
P0139 HO2S Slow Response Bank 1 Sensor 2 (was already disabled / no error reported)
P0140 HO2S Circuit Insufficient Activity Bank 1 Sensor 2
P0141 HO2S Heater Performance Bank 1 Sensor 2
P0420 Catalyst System Low Efficiency
P0430 Catalyst System Low Efficiency Bank 2 (was already disabled)
P2A01 O2 Sensor Circuit Range/Performance Bank 1 Sensor 2


hopefully that will do the trick...

 

Which other things, (besides the cat) does the 2nd O2 provide info for???

 

I reinstalled the rear O2 & temporarily removed my wideband. I also re-enabled the rear o2 codes.

Initially my LongTerm Fuel trims (LTFT) were averaging over 14 with out the rear O2. now they have settled down to where they belong & I think fuel economy has went backup again

I guess it's time to weld the supplied bung in for my wideband...

 

I would place the wide band in the rear bung, depending on the header collector and placement of the front bung there may be some discrepancies in exhaust flow causing misreads. The front is used for engine fueling to the PCM so don't remove/replace that one with the wideband. Otherwise you will have to remap the entire PCM file to accommodate the voltage change from your new wideband. Install it in the rear bung, and use an O2 emulator as mentioned before then run your wideband into a stand alone gauge.