PLX SM-AFR Wiring + Questions

Hello, I hope I’m not going to be shunned, but I would like to wire the device up to an oem, not chipped, P74/P75 OBD1 ECU. I have a single O2 bung.

I was hoping to wire this wideband sensor. Then using the narrowband emulation back to my ECU. (D14 I believe) Additionally, I believe that I need to bypass the O2 Heater sensor. Does anyone have recommendations or a diagram for this setup?

I tried to search and apologize if I missed something. Also, this was a handed down setup from a friend which is why I’m implementing it. Thanks for any help!

Just to clarify, you want to replace the stock narrow band with the wideband and have the stock ecu get readings from the wideband instead of the narrowband? Youre trying to do it this way since you only have one o2 bung on your exhaust?

That’s correct. I believe the control box for the Plx has an emulator to output these readings. Single bung with Bosch to control box to ecu is what I gather. I’ll go wideband to a Hondata unit in a few months, but it’s a race car only with no forced induction and the Plx unit was free to me.

Thanks!

i ran this set up before. u just run the 1 wire from the plx box to the correct pin on the ecu and bam it works. no more stock o2 sensor needed in car, and u have that added benefit of your wideband, plus if you run a hondata, then u get the ability to log your AFR as well…

You rock. Thank you so much. Are there extra wires for the O2 heater, just a little confused on that one. Or do I live with a cel?

i am not sure, i think in my hondata i had a way to just turn it off… this was almost 2 years ago that i had this set up. and it will probably be another year till i do it again.

I used to have a PLX, and a chipped ecu on crome. I cut the end off the stock 02 and wired the heater circuit, and narrowband circuit back into the connector and just plugged it back in. Then ran the wideband output back to my gauge.

Now with S300 I have an AEM UEGO, and run the same setup, except now I replaced the narrowband wire with the wideband directly to the ecu.