Weird O2 readings

[Sportsguy83]

Originally Posted by welllam

If i use the same ground for the aem gauge and also the same for the output ground, is this the same reference?
@Sportsguy83 i connect my ground of both to the same fuse box bolt that you uses and also poeer from the fuse top of the drl. So connection wise it should be similar. Just dont get it...

Yes, you are using my same configuration.... Definitely weird.

If all else fails, I believe you can change the parameters of the custom map and modify them to follow your actual Gauge readings properly.

[sw20kosh]

Originally Posted by Sportsguy83

Yes, you are using my same configuration.... Definitely weird.

If all else fails, I believe you can change the parameters of the custom map and modify them to follow your actual Gauge readings properly.

I might have missed something. What issue is he having?

[Sportsguy83]

Originally Posted by sw20kosh

I might have missed something. What issue is he having?

He has the Failsafe connected like me (the failsafe has an analog output cable which can be used to log via Ecutek custom map), to the ECU via rear O2 sensor connection and his Logs are showing a different value when compared to the gauge itself readings.

[sw20kosh]

Originally Posted by Sportsguy83

He has the Failsafe connected like me (the failsafe has an analog output cable which can be used to log via Ecutek custom map), to the ECU via rear O2 sensor connection and his Logs are showing a different value when compared to the gauge itself readings.

Oh gotcha.

I am going to follow these instructions then for grounding:

The BLACK wire should be grounded to a solid ground source. The
best possible ground source would be the battery ground (-) post.

[Ross]

When all else fails us the battery negative post. With innovate products I find that to help. Have not had an issue with aem units yet

[stugray]

This is where "grounding" gets a little confusing.

The meter/O2 gauge needs +12V power so it needs a ground (called a 'return' in my business because it intentionally carries the return current to the power source).
This would go to the battery negative.

The part of the system performing the voltage measurements within the O2 sensor needs a ground 'reference'.
This ground does not carry any significant current so it does not experience voltage drop during operation.
That ground 'reference' should go from the Measuring unit (gauge or ECU) all the way to the sensor.
Some older sensors (VDO oil pressure for instance) did not provide a dedicated ground to wire to and depended on the car chassis to provide the path.
Newer sensors typically have dedicated reference 'grounds'.

Theoretically, you could hook the reference wire to car chassis at the sensor end and at the gauge end and in most cases it will work.
Is it accurate? Each installation could be different and give different results.

[gabeg86]

i have also been told the stock sensor reads lean when hot/upper rpms, but my O2 readings are very low 11's to even sub 11's when WOT past 5k rpms on pump gas (91) with the stock sensor. i ended up rescaling my MAF in closed loop since my trims were off a bit. i don't have a wideband so i don't want to rescale open loop myself, but i just thought my logs looked strange... almost identcial to OP's

http://www.datazap.me/u/gabeg86/post...g=0&data=1-5-7

[sw20kosh]

Originally Posted by stugray

This is where "grounding" gets a little confusing.

The meter/O2 gauge needs +12V power so it needs a ground (called a 'return' in my business because it intentionally carries the return current to the power source).
This would go to the battery negative.

The part of the system performing the voltage measurements within the O2 sensor needs a ground 'reference'.
This ground does not carry any significant current so it does not experience voltage drop during operation.
That ground 'reference' should go from the Measuring unit (gauge or ECU) all the way to the sensor.
Some older sensors (VDO oil pressure for instance) did not provide a dedicated ground to wire to and depended on the car chassis to provide the path.
Newer sensors typically have dedicated reference 'grounds'.

Theoretically, you could hook the reference wire to car chassis at the sensor end and at the gauge end and in most cases it will work.
Is it accurate? Each installation could be different and give different results.

That is way over my head. lol

The LC2 wideband has 2 wires that need to be hooked up. One is a Switched on 12V and one is a ground. The instructions say to use the battery ground (-) post.

[stugray]

Originally Posted by sw20kosh

The LC2 wideband has 2 wires that need to be hooked up. One is a Switched on 12V and one is a ground. The instructions say to use the battery ground (-) post.

The two wires you are talking about are power for the controller.
I would call them Power (+12V - RED) and Return(Ground-Black) and can both go straight to the battery (with fuse of course).
Or can hook to a fuse panel (+) and chassis (-)

There are other wires that go from the O2 sensor to the gauge.
These are in the "Sensor cable connection"
As long as you use the cable provided with the unit, you are fine.
It is when people try to extend THOSE signals you can get into trouble.
The old school thinking is you can just hook up the "ground" in that cable to the car chassis and it will work.
It wont.
If your cable is intact from the factory, then you are doing it right.