Lean idle when going to closed loop fueling

[pman92]

Has to be either the WB is reading wrong, or the NB reading wrong.
If the NB are cycling between 0 and 1 volt the WB should be reading 14.7 at that point.

Could it be the scaling of the WB output? Im not sure if your logging WB data or using a seperate gauge, but in 12P there are 2 scalers that set the 0 and 5v values of the WB output (or maybe the 10AFR and 20AFR values, I can't remember, its been a while). Theres also some ECU's / inputs that benenfit if a pullup resistor is removed.

I know this isn't 12P, but could there be something similar going on?

[immortality]

I was tuning a L67 recently (VS) and the wideband is reading wrong almost the same amount as this one is (almost one whole ratio leaner). Unfortunately I also believe it has the faulty VS O2 sensor fault as it has the lazy O2 sensor issue going on.

Generally speaking, more often then not, if both the NB sensors are showing the same with plenty of cross counts then chances are they are correct.

Never got to finish the tune as the car had a woopsie out on the street (other drivers fault) so is awaiting repairs before we get to work on it again.

That car has a Innovative WB fitted. I like the 14point7 ones as they put out 3 different voltages during the start up cycle which should correspond in the tune to ensure the output and tune/definition are correct for an accurate reading.

[Nesr]

Has to be either the WB is reading wrong, or the NB reading wrong.
If the NB are cycling between 0 and 1 volt the WB should be reading 14.7 at that point.

Could it be the scaling of the WB output? Im not sure if your logging WB data or using a seperate gauge, but in 12P there are 2 scalers that set the 0 and 5v values of the WB output (or maybe the 10AFR and 20AFR values, I can't remember, its been a while). Theres also some ECU's / inputs that benenfit if a pullup resistor is removed.

I know this isn't 12P, but could there be something similar going on?

Yeh it’s weird that both NB are doing the same thing. i’m using a separate gauge

[Nesr]

I was tuning a L67 recently (VS) and the wideband is reading wrong almost the same amount as this one is (almost one whole ratio leaner). Unfortunately I also believe it has the faulty VS O2 sensor fault as it has the lazy O2 sensor issue going on.

Generally speaking, more often then not, if both the NB sensors are showing the same with plenty of cross counts then chances are they are correct.

Never got to finish the tune as the car had a woopsie out on the street (other drivers fault) so is awaiting repairs before we get to work on it again.

That car has a Innovative WB fitted. I like the 14point7 ones as they put out 3 different voltages during the start up cycle which should correspond in the tune to ensure the output and tune/definition are correct for an accurate reading.

Yeah I'm not sure. I'm leaning towards faulty NB's because its only reading off when in closed loop idle n driving. As soon as i go into PE or in open loop idle it reads spot on.

[immortality]

But is it?

Unless you are running a stock tune on a stock motor you can't be sure the tune is right.

Somewhere earlier in the thread it was mentioned the injector data looked wrong. When in PE the PCM is calculating the amount of fuel to add based on airflow/rpm using the injector data and various offsets like air temp, engine temp to calculate injector PW. If one data point is off then the calculation is wrong and since you have changed the target AFR's it may just be a co-incidence that they roughly match up.

But change the NB sensors and see what happens, it'll either change or it won't.

[Nesr]

But is it?

Unless you are running a stock tune on a stock motor you can't be sure the tune is right.

Somewhere earlier in the thread it was mentioned the injector data looked wrong. When in PE the PCM is calculating the amount of fuel to add based on airflow/rpm using the injector data and various offsets like air temp, engine temp to calculate injector PW. If one data point is off then the calculation is wrong and since you have changed the target AFR's it may just be a co-incidence that they roughly match up.

But change the NB sensors and see what happens, it'll either change or it won't.

I'll see if I can get a replacement WB n go from there