do i need an o2 sensor

[gexgexgexgex]

i just bought my megasquirt and spark extra from ra motorsports and do i really need to hook up an o2 sensor, i dont care about gas milage so do i need it or is it just like tha o2 sensor on the 280zx where it does nothing

[mobythevan]

If you had a wideband it would probably make more sense to hook up and use target AFR tables. I don't use the NB sensor. I set EGO settings to not use the NB sensor until I'm above 6500rpm, thereby disabling it.

[gexgexgexgex]

thanks for the info on it, i plan on using the wide band to tune so i should be ok

[Guest bastaad525]

but does MS need feedback from the O2 to run properly? I know my stock Nissan doesn't god my EFI is so screwy right now....

[mobythevan]

From what I have seen, people who have problems running with the O2 sensor connected have exhaust leaks upstream of the sensor. MS in theory will run in closed loop mode using the O2 sensor, but I haven't tried it because I tuned my cruising AFRs to about 15.3:1 so the ECU would try to go back to 14.7:1 if I turned it on to use the NB sensor.

[Tony D]

unless you had a WBO2 box with a configurable switching output to the MS...

 

Then you could set your EGO correction to any number you wanted.

This is how the WBO2 worked in the original Electromotive TEC2 using target AFR. You set your cruise bins to the target and the O2 sensor did a correction offset to the programmed table.

 

Actually, with that setup, it was pretty easy to rough in a table, turn on datalogging, and simple record the offset lambda number the ECU was giving to reach the desired AFR, and then go make that adjustment to the hard-programmed table. When you were done, a good table would have "0" correction no matter how you drove it (under most reasonable circumstances).

 

But I digress...

 

My plans for the future is to set up the AFR Switching output from a WBO2 unit and use IT for the EGO correction at cruise. For my long trips, even a few thenth's of a AFR will save gas money... Mind the EGT and all will be well.

 

Another thing to remember is to cap the range where the EGO is active, and to put reasonable correction ranges on the adjustment the O2 will be able to make. But a narrow-band is a real limitation, the real way to go is a WBO2, and just skip the old technology altogether.

[mobythevan]

I need to get my WBO2 hooked to the MSnS_Extra so I can use those target AFR tables, so many things to do. The instructions are written up for using the Tech Edge WBO2 like I have. I am still waiting on my v-band flange for the new turbo.

[jkube]

If I remember correctly for the basic MS you can set the EGO parameters to shut it off completely, allowing for better tuning. I think there is a paragraph about this in the Megamanual

 

Should be the same for MSS

 

I guess you could set the software to shut the EGO off and just not install a sensor.

 

http://www.execulink.com/~jkube/Mainpage_lethalzs.html

[1 fast z]

I DONT run any O2 sensor with my MS setup. I just leave the WB on all of the time and moniter it that way.