Proper Placement of O2 Sensor

[RobertISaar]

i tend to tighten them up as much as possible, since it will keep the INT closer to a single point, rather than having to swing everywhere to make the O2 do what the PCM wants.

no idea on what it does to emissions, but it does keep me at a single AFR better.

[PJG1173]

i tend to tighten them up as much as possible, since it will keep the INT closer to a single point, rather than having to swing everywhere to make the O2 do what the PCM wants.

no idea on what it does to emissions, but it does keep me at a single AFR better.

are you talking about the O2 windows?

[RobertISaar]

both, actually. i tighten the windows to within 1 or 2 A/D counts of each other at all times, but i also have the fueling prop settings set pretty mild.

[PJG1173]

while we are on the subject of o2 sensor placement... Lets say someone installed long tube hedders and installed the factory heated O2 sensor in one of the collectors. now the sensor shows the engine is lean and tries to add fuel in closed loop causing it to run real rich. How would someone correct that?

[PJG1173]

both, actually. i tighten the windows to within 1 or 2 A/D counts of each other at all times, but i also have the fueling prop settings set pretty mild.

hmm you lost me at A/D counts. what are A/D counts?

[RobertISaar]

O2 sensor A/D counts. 1 count is ~4.42mV.

so my rich and lean tables are 4.4-8.8 mV away from the mean table in all locations.

[PJG1173]

O2 sensor A/D counts. 1 count is ~4.42mV.

so my rich and lean tables are 4.4-8.8 mV away from the mean table in all locations.

Ok I think I'm following. still not getting what A/D stands for. when you say prop gain are you talking of the setting like this "Proportional Gain if Rich (Stable)"? if so how does this work?

[RobertISaar]

A/D: analog to digital. it's how the PCM interprets sensors. since it has an 8-bit A/D system, there are 256 possible counts. 0 counts for a 5V sensor is 0volts, while 255 counts is 5 volts, with steps of .0196 volts in between each count. with an O2 sensor, the range is significantly smaller, on the range of 0-1127mV.

"Proportional Gain if Rich (Stable)" sounds like the A1 equivalent of "Gain Factor for Positive O2 Error (KPERMOD)", which isn't what i'm reffering to.

i'm reffering to:

Prop Counts when in Prop Duration 1 (KPCNT1)
Prop Counts when in Prop Duration 2 (KPCNT2)
Prop Duration 1 When Idling (KIDLPD1)
Prop Duration 2 When Idling (KIDLPD2)
Prop Counts Gain When Idling (KIDLGF)
Prop Error Gain Factor vs Airflow (F6CLTBLB)
Prop Counts vs Error (PCCNT) (F9CLTBL)
Prop Duration 1 vs Airflow, When not Idling (F12CLTBL)
Prop Duration 2 vs Airflow, When not Idling (F13CLTBL)

not all masks will have the same scalers/tables, and even more likely that their naming will be quite different, but those are the major O2 prop settings for A1/DF and any other MPFI 60V6 mask.

[PJG1173]

Ah I see thanks for the clarification.

[EagleMark]

while we are on the subject of o2 sensor placement... Lets say someone installed long tube hedders and installed the factory heated O2 sensor in one of the collectors. now the sensor shows the engine is lean and tries to add fuel in closed loop causing it to run real rich. How would someone correct that?

Tune the chip!

Make sure you have no exhaust leaks. Somtimes you can hear them when reved up causing pressure others you can't. Exhaust causes pulsations and a vacuum in areas sucking in air. Is it really rich? How do you know? Your nose is a terrible indicater especially without a cat. Looking at spark plug color is way better. WideBand O2 sensor on other side would be a good way!

wow Robert that was some great info!

[PJG1173]

Tune the chip!

Ok figured that...

Make sure you have no exhaust leaks. Somtimes you can hear them when reved up causing pressure others you can't. Exhaust causes pulsations and a vacuum in areas sucking in air. Is it really rich? How do you know? Your nose is a terrible indicater especially without a cat. Looking at spark plug color is way better. WideBand O2 sensor on other side would be a good way!

no exhaust leaks, Sniffing exhaust gasses is bad for your health, soot on plugs, WBo2 on other collector says rich, and the NB band is new.

[EagleMark]

Well you got er figured out! Headers alone made that much difference? Must be maxing out rich BLM... sometimes lowering that point gets you more BLM numbers to work with. I us an AutoProm so I get em in the ballpark live before I start data looging BLM numbers and making finer adjustments.

[RobertISaar]

narrowband shows lean, wideband shows rich, plugs are covered in soot.

sounds like the narrowband isn't working properly, even with it being new.

[JeepsAndGuns]

Would the long tube headers placing the 02 further away from where it was stock, and since the headers shed more heat than cast iron manifolds be causing this problem?
What about wrapping the headers in that insulation, to keep heat out of the engine compartment and in the exhaust?

[EagleMark]

Could be but he would see that in O2 not ready or closed loop. Wrapping headers does keep heat in, also keeps moisture in and rots them...