Replace factory O2 with wideband

s300 and SManager software questions & answers
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boostedgsr2.0
Posts: 4
Joined: Sat May 09, 2020 9:48 am

Replace factory O2 with wideband

Post by boostedgsr2.0 »

I have a obd1 B18C with S300

I wanted to get rid of my factory o2 and only use a wideband. My understanding is that I can remove the factory o2 and replace it with a plx wideband since it has both a narrow and wideband signal.

Can someone please confirm they have done this?

If so is this the correct part to get? Wasn’t sure if the sensor module would be required.

https://www.plxdevices.com/Wideband-O2- ... 002726.htm
DaX
Posts: 654
Joined: Tue Mar 18, 2003 3:48 pm

Re: Replace factory O2 with wideband

Post by DaX »

Yes, that is the wideband I'm using, but I got the package that came with the gauge as well. You will need the sensor and module that comes from PLX.

Since you're running an S300, you won't use the narrowband output - that would only be used if you were using a stock ECU. With the S300, you should disable your ELD in SManager, cut R136 and R138, and put the wideband input into D10. You can then continue to run the car in closed loop and the S300 will use the wideband signal for control.
boostedgsr2.0
Posts: 4
Joined: Sat May 09, 2020 9:48 am

Re: Replace factory O2 with wideband

Post by boostedgsr2.0 »

I was under the assumption narrowband is also needed to run closed loop.

Also what are the R136/138 wires?
DaX
Posts: 654
Joined: Tue Mar 18, 2003 3:48 pm

Re: Replace factory O2 with wideband

Post by DaX »

I was under that assumption too when I installed mine, but the S300 can handle closed loop control with a wideband input. I initially had the PLX narrowband output wired into D14 (O2) and the wideband output going into AN1 on the S300. It wasn't running right and Spunkster told me how to hook it up correctly.

R136 and R138 are resistors in the ECU. If you use D10 (ELD) for your wideband input, you need to cut these resistors out of the ECU to get the full 0-5V range of the input.
boostedgsr2.0
Posts: 4
Joined: Sat May 09, 2020 9:48 am

Re: Replace factory O2 with wideband

Post by boostedgsr2.0 »

Thanks for the info. I found this old post that mentioned narrowband is required to run in closed loop. It’s an old post so not sure if this is still the case.

viewtopic.php?t=8423
DaX
Posts: 654
Joined: Tue Mar 18, 2003 3:48 pm

Re: Replace factory O2 with wideband

Post by DaX »

Could be that I misunderstand too, as I am not running closed loop. Here is the thread where I was talking to Spunkster about it last year:

viewtopic.php?f=19&t=22358
spAdam
Posts: 57
Joined: Sat May 03, 2014 5:34 pm

Re: Replace factory O2 with wideband

Post by spAdam »

The
boostedgsr2.0 wrote: Sun May 10, 2020 3:27 pm I was under the assumption narrowband is also needed to run closed loop.

Also what are the R136/138 wires?
The S300 actually does closed loop quite well with the wideband, but you'll need to do some tuning on the control to get it really dialed in. Best part is that you're not married to a single lambda target that way, you can have different target for different conditions (load based, warmup, etc)
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