A/F and O2 help

[bullet87]

My A/F ratio is at 13:1.1 at 4150 Rpm and my O2 volts are 129mv, whats wrong with this picture?

[Joe Lubrant]

My A/F ratio is at 13:1.1 at 4150 Rpm and my O2 volts are 129mv, .................................................. .................................................. .whats wrong with this picture?

Whats wrong with what picture your Avatar or your A/F :fragez: :SHOCKED:


Can you give a little background on set-up, Inj, turbo, WideBand 02, ScanTool, WOT or Part Throttle...Boost etc. etc.


Joe

[bullet87]

83 lb injectors, 340 walbro, hot wire kit, Max Effort, 62/83 G Turbo, Part throttle, boost about 10 lbs, 3" down and single exhaust, pretty heavy cam, 70mm TB with precision Plethum and RJC Power plate, MSD 8.5 wires, gap at .43, 3000 stall let me know if you need anything else.

[turbodave]

My A/F ratio is at 13:1.1 at 4150 Rpm and my O2 volts are 129mv, whats wrong with this picture?

DO NOT, let me repeat, DO NOT ever use DS for reading A/F ratio. It has absolutely nothing to do with reality. As much as I love DS, and rely on it heavilly, there are some things in it that are just not realiable. A/F ratio is not a value pulled from the ECM, or even a value that the ECM calculates and sends down the data stream. It is strictly a value calculated by DS based on some pretty loose calculations the ECM is making.
Trust me it's not a reliable value to look at.
If you need to know an acurate A/F value, the ONLY way you'll read it is via a wideband O2 sensor.
As for what your O2's are reading, it depends on the quality of the sensor, it's age, how much lead fouling it might have been subjected to, etc. etc. and only then it's not terribly accurate or reliable if it's a swithing (regular) O2. Again, a wideband O2 is required if you're serious about getting accurate readings.

[Joe Lubrant]

DO NOT, let me repeat, DO NOT ever use DS for reading A/F ratio. It has absolutely nothing to do with reality. As much as I love DS, and rely on it heavilly, there are some things in it that are just not realiable. A/F ratio is not a value pulled from the ECM, or even a value that the ECM calculates and sends down the data stream. It is strictly a value calculated by DS based on some pretty loose calculations the ECM is making.
Trust me it's not a reliable value to look at.
If you need to know an acurate A/F value, the ONLY way you'll read it is via a wideband O2 sensor.
As for what your O2's are reading, it depends on the quality of the sensor, it's age, how much lead fouling it might have been subjected to, etc. etc. and only then it's not terribly accurate or reliable if it's a swithing (regular) O2. Again, a wideband O2 is required if you're serious about getting accurate readings.


Agree!!

Also I wouldn't trust any type of Part-throttle readings including MV...to much transitioning from being in power enrichment state to non enrichment or de-cel.

I would only have partial trust in MV readings under Wide Open Throttle and boost used there.

Joe

[GNRick]

How do you tune with a wideband? Julio says to shoot for 10.5:1, with alky. How do you do this? Adjust fuel pressure, adjust translator, or send the chip back to the programmer?

[Eric Marshall]

It depends on what chip you have. If it's adjustable, you can increase/decrease WOT fuel through the chip. If it's one of my chips (TT), you can look at the chip to see what version is it (top left corner usually), and download the instructions from the download section of my site, www.turbotweak.com/forum (http://www.turbotweak.com/forum).

If you have an Extender chip and a Translator, you can use the WOT knob in the Translator box to adjust fuel.

[GNRick]

Eric- why don't you just program the chip to command a desired AF ratio? The chip could add/reduce fuel based on whatever air value it is seeing from the MAF.

[Eric Marshall]

There is no air/fuel feedback into the ECM when in boost, so it doesn't know what the actual air/fuel ratio is. I do have other chips that use a wideband O2 for feedback (connected to a Powerlogger), and you can command a target air/fuel ratio.