Wideband O2 on Renix?

[cruiser54]

https://www.cherokeeforum.com/f24/renix-wideband-oxygen-sensor-272305/

[ghetdjc320]

3 hours ago, cruiser54 said:

https://www.cherokeeforum.com/f24/renix-wideband-oxygen-sensor-272305/

Says I have to have a login to view the conversation. Mind posting up the info?

[Htchevyii]

I can't see it either and I was logged in. There is some info on Nick's own page.

 

https://nickintimedesign.com/rem-wideband-converter/

 

[cruiser54]

How to convert an '87-90 Jeep Renix 4.0 to run on wideband oxygen sensor

This is possible thanks to the NickInTimeDesign REM. I'm using the dash/clock version. Very nice.

This is the latest wiring recommended by Nick as of 3/25/24. This applies to any wideband controller with a 0-5v signal output. I'm using an Innovate LC-2 with a Bosch LSU 4.9 oxygen sensor.

Process

Innovate's instructions say DO NOT wire the controller power to any shared power source, so I wired a 4p relay w/ a fuse off the battery to provide 12v to the controller.
The relay can be triggered by any 12v ignition power source.

Relay mounted near the battery.


Find a safe place to mount the controller and route the wiring through the firewall.


Connect the 0-5v signal output from the wideband controller to port 1 of the REM serial adapter for dash/clock versions. (purple wire in pic)


While you're there, grab your o2 heater relay and either replace it with a 4p relay or remove the center lug with a small pair of pliers.
*Yellow X in pic, but not all relays are in the same order. Make sure it's the one with 2 orange/black striped wires going to the center pin.
Doing this prevents 12v from getting sent down our new o2 signal line, but still allows full power to be sent to the fuel pump during WOT.
To return to factory simply replace this relay and install a factory o2 sensor.


Remove your old o2 sensor & install your new wideband o2 sensor into the factory o2 bung. Be sure to calibrate the new sensor before installing it into the exhaust, and periodically per the instructions. This may not apply to other brands.
Make sure everything is connected and tuck the excess cable in a safe location away from heat etc. I ran mine under the booster and into the corner.


Grab your old o2 sensor, chop the plug off, and connect the two outer wires together. Now plug it back into the factory harness like the original o2 sensor.
This sends the new o2 signal provided by the REM back to the factory ECU.


Pop the cover off the back of your REM and locate the SIG/HTR dial. Turn it to SIG.


Install the REM and navigate to More -> Settings -> Wideband -> and set Wideband Pin to Port 1, then select the AFR range compatible with your controller's output.
I had to reprogram the output on my controller to match one of the ranges available on the REM.
Nick has since released an update to support Innovate's 7.35-22.39 AFR range: https://drive.google.com/file/d/1-AW...ew?usp=sharing

Results
My XJ now stays in closed loop and has better acceleration and fuel economy than ever before. The fun part with this, besides throwing an Innovate sticker on the side of your Jeep, is being able to adjust the target A/F ratio.
This is essentially piggybacking 101: intercept a signal, modify it, and send the modified signal back to the ECU to get the desired effect/response. The default setting is 14.7:1 which is the ideal ratio for the cleanest burn. Lower is richer, higher is leaner.
This has been the single biggest improvement to my Jeep's performance and acceleration. I've done all of the Cruiser54 tips, new power cables & good grounds on everything, fat plug wires, new cap/rotor, indexed dizzy, proper TPS adjustment, full exhaust etc etc. None of those "mods" did anything close to what the wideband has done. If you haven't done all the typical Renix tune-up stuff then you may not reap the benefits of the wideband until you do. Always perform mods on a healthy motor or you're wasting your time and money.

Renix Wideband Target Tuning

 

Gas Mileage
I ran a few tanks of gas at different target settings and different octanes to see what's actually happening:
14.5 A/F on 87 octane for 172 miles: 15.4 MPG
14.7 A/F on 87 octane for 166 miles: 15.7 MPG
14.5 A/F on 91 octane for 146 miles with A/C running: 16.9 MPG
14.5 A/F on 91 octane for 208 miles, some A/C: 18.2 MPG
14.7 A/F on 91 octane for 209 miles: 19.2 MPG!!

Renix engines have a knock sensor, '91+ does not. We like our knock sensors. This means the engine will advance timing as much as possible until knock is detected (to maximize power). This also means Renix engines will adjust to higher octane fuels because there's less knock. You can also set the REM target to a richer setting and watch the knock disappear. This allows the engine to advance timing more than it would on lower octane fuel which results in more power, requiring less foot to get up to speed, and better fuel economy.

Here's a pic from a recent trip to Lake Tahoe (the last two trips from above). A mix of traffic, 80mph straights, hill climbs, and twisties.
14.5 target AFR was great for hills. If you have a power/comfort trans switch leave it on power and forget it.

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Last edited by 4pointHo; Today at 10:26 AM. Reason: relay order

     

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