reading air fuel

[Ruben2]

Just got HP tuners and did my first log today. I've never done tuning before.
I'm trying to figure out if I'm running rich or lean.

This might be dumb, but in the histogram I click on the air/fuel tab and it shows this chart. I'm assuming it's the RPMs going accross and something else going down. all the numbers logged onto the chart are between 63 and 961. I'm just wondering what these numbers are. I guess I thought it would just show me 12.8:1 or 14.6:1 or numbers like that for each RPM.

[pknowles]

It's showing you the voltage of you narrowband O2's. You can't obtain a reliable AFR from the narrowband O2's because their measurement is sensitive to temperature and is only accurate around 14.7 AFR which is about .450 or .500 volts (can't remember which). Don't be alamed by very high and low reading on you narrowband O2's, they are designed to swing back and forth like that. So don't think if you have a value of .062 volts that you are way lean because you might just be in a low part of the O2 occilation. You need a wideband O2 to get an accurate AFR.

[12secSS]

Also the "something else" on those charts are the load on the engine values. The higher the number (going down the chart), the more load is on the engine. You'll see this more apparent when you accelerate hard or are going up a hill.

[Ruben2]

So if the number is like 800. that means it's .800mv? I know they aren't that accurate but I just wanted to get a good enough grasp as to whether or not I'm running extremely lean or not under WOT.

Another question. what are the numbers going down under advance and retard represent?

[horist]

800 = 800 millivolts

The o2 sensors operate on 1 volt, so the values are always mv

before I got a wideband I subscribed to the theory too rich is better than too lean, so I'd try to keep my O2 sensors at 940-950, others go with 920ish

[Hot_Karl]

well I just logged my first scan today and I had some values in the 100mv range. This was just driving around normal. I haven't gotten far enough to want to try to correct them just yet(got my software yesterday), but does that mean I'm running Uber lean? I would think if it was really that bad my motor would have gone by now...

[xonelith]

Since I'm a beginner, I'm pretty much comin' from the same spot. This is what I've learned.

Ignore these readings except at WOT (since we are learning here). They won't help much or tell you much.

At WOT, on an NA motor, 890 - 920 is supposed to be good. I'm at 960 or so, but that apparently is ok for my cam (Plugs look good and AF on Dyno was good). Boosted motors should be higher (960ish).

Someone could probably correct me

[mtcrusan]

What I understand from reading this forum is that you are concerned about your O2 voltages at WOT (Wide Open Throttle). So 100 during normal driving is nothing to be worried about.

Please correct me if I'm wrong and explain why? :huh2:

[Bill@HPTuners]

Since I'm a beginner, I'm pretty much comin' from the same spot. This is what I've learned.

Ignore these readings except at WOT (since we are learning here). They won't help much or tell you much.

At WOT, on an NA motor, 890 - 920 is supposed to be good. I'm at 960 or so, but that apparently is ok for my cam (Plugs look good and AF on Dyno was good). Boosted motors should be higher (960ish).

Someone could probably correct me

ok check out my csv logs http://www.clubgp.com/newforum/fb.as...&m=2521383 to give an exact # as to whats good & what isnt is impossible...as you can see i range from 850-950mv's from 10.7:1-12.1:1 bottom line is theres very little coralation between your narrowbands and what a wideband would read.

[Bill@HPTuners]

What I understand from reading this forum is that you are concerned about your O2 voltages at WOT (Wide Open Throttle). So 100 during normal driving is nothing to be worried about.

Please correct me if I'm wrong and explain why? :huh2:

personally I pay very little attention to stock o2's unless they are lazy or dead or dont go to +800mv once your at wot.

[LITTLEELVISDAN]

On the dyno now and the HPTuner kit is reading milivolts for the A/F ratio. I need real A/F ratios to properly tune. Does anyone have a conversion table?

[Bill@HPTuners]

There is no conversion.

Get a wideband setup.

[LITTLEELVISDAN]

The caddy STS-V comes stock with a wideband 02 sensor. If its sending it why cant the HPTuner not read it?

[LITTLEELVISDAN]

I called Caddy and they confirmed the STS-V has 4 02 sensors. 2 pre and 2 post. one ofthe pre sensors is a wideband. I have also confirmed the EFI Live kit reads the ecm properly and gives A/F ratios. How do I get the HPTuner to read it?

[LITTLEELVISDAN]

I also don't see any VVT setings in your software. Does HPTuner kit really support the STS-V?

[EC_Tune]

Yes HPT does. No there are no VVT settings at this time. And no the STS-V doesn't have wideband o2's. The SRX does.

[LITTLEELVISDAN]

Yes HPT does. No there are no VVT settings at this time. And no the STS-V doesn't have wideband o2's. The SRX does.

Straight from Caddi.. "The pre-cats on the STS-V are Lambda sensors, the post cats are conventional O2 sensors (heated).

Lambda sensors usually read a value of .998 or close. If you are not familiar with them they don't use mV for readings, the ECM tries to keep the Lambda value constant by adjusting current flow to the sensor. The computer then monitors the current flow to adjust fuel trim. The post cats read mV but they are not used for fuel trim, at least not completely. They are mainly catalyst efficiency monitors."

So how is the EFI Live kit reading in A/F ratios and hte HPTuers kit reading in Mv? Mv is a post cat o2 sensor output NOT the Pre Cat Lambda o2 sensor.

[Bill@HPTuners]

Post a csv file of the efilive scan so we can verify, as well as what year STS-V your talking about so I can look up the PN's of the front o2 sensors so I can verify if they are truely wideband sensors. The only GM vehicles I was aware they used widebands on are the 2.0t vehicles.

I have a feeling they might be scanning commanded lambda ratio but impossible to speculate without more info.

[LITTLEELVISDAN]

Post a csv file of the efilive scan so we can verify, as well as what year STS-V your talking about so I can look up the PN's of the front o2 sensors so I can verify if they are truely wideband sensors. The only GM vehicles I was aware they used widebands on are the 2.0t vehicles.

I sent a mail with all that to ken. I'll forward it to you.

[LITTLEELVISDAN]

Ifyou don't get in in about 10 min then its my wireless sprint card blocking my outbound mail. You might have to get ken to forward you a copy if that happens. It got blocked sorry. maybe Ken can forward it to you?