p72 s300 v3 NA b16a innovative MTX-AL wideband sensor

[sh1ntaox]

I have read up on as much of this topic as i can find and have seen that it varies with setup choice to some extent. i haven't seen any info on this specific setup and am confused which way to go. 1989 civic si ED7 running a first generation b16A naturally aspirated on a p72 with s300 v3. the wiring harness is Rywire obd0 to obd1 as well the bSeries harness. it is running on a basemap for the break in period and is showing no check engine light running the stock o2 sensor. i have another bung welded on and was aiming to hook up the innovative wideband and run as well. based on what i have read from multiple different sources i am pretty confused which pins should be tapped to make this function. innovative MTX-AL is the sensor kit its the BOSCH LSU49 sensor. initially i was looking to just run the wideband sensor in place of the stock o2 sensor and just keep a single bung but wasn't into the idea of trimming resistors to get the full voltage out of pins. this is why i was trying to have both running. is it possible and safe to run both the stock o2 sensor and the wideband sensor on a separate bung simultaneously ? with this specific setup what are the best pin choices to tap?

[Spunkster]

Yes you can do this, but you can run just one sensor and run closed loop with the wideband. ELD (D10) in put is best. You only have to cut one leg of the resistor and can always solder it back down if you want.

[sh1ntaox]

please correct me if im wrong. running open loop will default to stock air fuel ratio settings of the stock O2 sensor. running closed loop will allow the wideband sensor to be auto tuned by the ecu to achieve optimal air fuel ratio over critical moments. they can not run together so its either open loop or closed loop. its fine to have the stock O2 sensor running for open loop to achieve no error codes but you are limited to the default air fuel ratio which means you really can’t tune it in open loop. regardless to adjust air fuel ratio via the wideband sensor voltage i need the clean 5V. D10 is the pin to tap? which resistor has to be clipped to achieve clean 5V signal on D10?

[Spunkster]

Open loop doe not use any oxygen sensor, it uses only the fuel tables. You do not need a narrowband sensor at all for this.

Details can be found in the help file: http://www.hondata.com/help/smanager/wi ... b=wideband

[DaX]

You can run both sensors, but it is cleaner and simpler to just run the wideband.

As Spunkster recommended, run the wideband sensor signal into D10 and cut out resistors R136 and R138 from the ECU. It's very simple to do.

I think you're a little confused about how open loop and closed loop work. The car switches between open and closed loop even on the stock ECU. As Spunkster said, running full time open loop the ECU will only look at the fuel tables and not make any corrections based off air fuel ratio that the ECU sees, whether that is coming from the wideband or the stock narrow band. Running closed loop (again, regardless of whether the ECU is using the stock narrow band sensor or aftermarket wideband sensor) the ECU will look at the fuel tables but will also make adjustments based on input from the narrow band or wideband, and will make these adjustments when the conditions are met which you can set on the "Closed Loop" tab in SManager.

If you look at the stock P28 calibration, the car will enter open loop if it sees any MAP pressure above 9.3 in-Hg, any engine speed over 4,812 RPM, and it starts in open loop and stays there for the first 30 seconds the ECU is powered up.