PCM Diagnostics & Tuning - Wideband permanent install?

I am about to embark into the tuning "learning pains" for my '98 WS6.

Thanks to Chad's (Green Light Motorsports) help, I ordered an EFI live V2 with and LM-1 wideband.
I went with the LM-1 so I can use it to tune my other cars.

My big question is this: After tuning your car, is it necessary to leave the wideband in? Is it best to leave one in? Is the PCM programmed to adjust AFR by watching the wideband sensor input and disregards the OEM o2 sensors?

Or once it is tuned with a wideband, do we leave it up the PCM to keep the AFR in check through the O2 sensors?

Thanks in advance for any inputs!

Yes you can leave it in the exhaust system.

Some Widebands simulate Narrow bands, so you could let the PCM use the sensor, and read the true WBAFR on the dash. The PCM cant read standard WB signals unless the sensor has a narrow band output.

Its not nessasary to leave the WB sensor in. Just tune the car for WOT runs with the WB sensor and for not WOT conditions the narrow bands will be fine. The Narrow bands are spot on for Stoch (14.6 AFR) the fuel trims will trim it to be pretty good, you may want to log the fuel trims and adjust your VE if its more than 4% out. Search for VE tuning on that.

I usually remove the wideband once im done tuning...especially the lm1 since you have to go through a whole ritual to preheat the sensor & such.

Thanks for the input!

I figured that was the case. We use the wideband to get the VE table where it should be and then leave the OE o2 sensors to trim the mixture after tuning.

I just thought there may have been a "mode" where the wideband would replace the OE o2 narrowband sensors.

Thanks again!

there is but to impliment it with an LM1 would be a pita. LM1 is meant for portability rather than functionality as a narrowband on a daily basis ;)

I've had my LC-1 permanently installed for a LONG time at this point (1.5-2 years)...I just keep it in my header collector since I run full time open loop. It has served me well along with the XD-16 gauge.

Wow, now I am back to being confused , LOL :cry:

Sorry for my ignorance or lack of tuning knowledge, but are you telling me you can leave a wideband in permanently to take in place of the OE narrowband o2 sensors?

So leaving it in open loop will ignore the OE o2 sensors and actually run off the readings from the wideband?

Please let me know.

Thanks!

Open loop means no feedback at all...it doesn't listen to the narrow band O2 sensors OR the wideband. That's why I leave mine in at all times...I don't want the feedback to influence the PCM (personal preference). I leave it in full time to monitor it myself...if I don't like what I'm seeing on the gauge, I go out and mess with the VE table some more (which isn't very often).

Sorry for the confusion...

Wow, now I am back to being confused , LOL :cry:

Sorry for my ignorance or lack of tuning knowledge, but are you telling me you can leave a wideband in permanently to take in place of the OE narrowband o2 sensors?
Yes, so long as the wideband has a 0v-1v output signal. This is all the stock computer needs to switch the fueling around in closed loop.

So leaving it in open loop will ignore the OE o2 sensors and actually run off the readings from the wideband?

Please let me know.

Thanks!
No! You must enable closed loop, but you will need splice into your stock harness or make your own connector plugs that will plug into the stock harness. You will need either two widebands or run the 0v-1v output signal from the wideband to the stock O2 harness plugs found on either side (I wouldn't recommend that).

ok, got it!

Thanks for the helping me undertsand this better, much appreciated :cheers:

Open loop means no feedback at all...it doesn't listen to the narrow band O2 sensors OR the wideband. That's why I leave mine in at all times...I don't want the feedback to influence the PCM (personal preference). I leave it in full time to monitor it myself...if I don't like what I'm seeing on the gauge, I go out and mess with the VE table some more (which isn't very often).

Sorry for the confusion...

Will Nitrous hurt the WB or regular o2 sensors?
What about race gas, 110 octane?

:)

If the Race gas has lead content then that will bugger the O2's.
Leaded fuel is a no no.

I beleive nitrious will be fine though.