PL and WB readings

[larrym]

OK I recently hooked up a powerlogger, at idle and cruise the power logger and the AEM gauge are pretty much bang on. WOT is a different story the gauge reads 10.8-11.0 and the PL is 10.2 my narrow band is .720-.760 which seems to agree with the wide band.

 

[aminga]

Here is a typical response curve around narrow band O2 sensor vs a wideband. Narrowbands are not meant for determining specific air fuel ratios but only as a fueling reference for the ECM. The ECM sees lean drives the fuel rich and then turns around and goes the other way. Trying to keep the air fuel rich and lean of stoich the same amount of time.

Bottom line is for a wideband it's pretty linear, if the voltage changes by 10% your air fuel has changed by 10%

For a narrowband if the voltage changes by 50% the air fule could have changed by 5% or 100% depending on where it is in the response curve. You can't say that .xxxMV = 10.2 A/F

 

[aminga]

Check the Powerlogger console for voltage offsets and other Go to tab 3 setup and look at the actual voltage the sensor is putting out. Key on engine off with your wideband should be close to 5V on the powerlogger

 

[TurboDave]

For sure!!! One should never use a NB value as a reference. For example, when my NB reads 760, I'm at 11.4 on the Wideband. Ignore the narrow band and just let it do its thing to keep the ECM at stoiceometric when it's called for.


Sent from my iPhone 6+ using Tapatalk.[emoji252]

 

[aminga]

Also check to make sure the ECM and Existing wideband gauge are grounded to the same spot.

 

[larrym]

Ah so add ground to the block the where gauge taps into the powerlogger I only have 2 reference wires into it now 1 for the wide band 1 for the map sensor.
Or ground the gauge to the ECM wiring?

 

[aminga]

Ah so add ground to the block the where gauge taps into the powerlogger I only have 2 reference wires into it now 1 for the wide band 1 for the map sensor.
Or ground the gauge to the ECM wiring?

Figure out what ground plane the gauge itself is on. Go from there.

 

[aminga]

If this is the gauge. Make sure the black goes to the engine ground (not chassis ground as stated)

 

[larrym]

Well that could be my problem right there

 

[larrym]

Thanks for the help Al
I did a little research and grounded the gauge to the computer case reads are very close now.