All O2 sensors created equal?

[EagleMark]

We all have to stop using AFR and start using Stoich or Lambda.

A wideband O2 sensor is not an AFR meter, it's a Lambda meter and then converted to AFR for a gauge or data reading. The wide band controller sets Lamda to 1.0 for the fuel you enter. 14.7 for gas but that is hard to find anymore. For E10 I have seen numbers from 13.8 to 14.3 the real issue is what do you have in your tank? Look at the pump it say CAN contain up to 10 % ethanol.

SO if your wide band is set to 14.7 and the AFR or Stioich in your bin is 14.7 then your analogue wideband says 14.6 AFR, it really isn't 14.6, but is actually 14.1 because the narrow band has corrected to Stoich of E10 fuel. Your LTFT are high... LTFT can be off in data as well becuse of BLM learn stored in ECM/PCM.

Don't beleive me? Hook your Lc-1 serial cable up to logworks, it's a true reading and has no analog voltage or ground issues, then change it over to Lambda!

Narrow band O2 sensor is desinged to correct to Stoich, it will correct fueling if you use gas or E10, for that matter it will correct to Stoich of any fuel. There's where all the STFT and LTFT come into play.

To tune with a wide band O2 sesnor data and adjust the VE table you need to disable all O2 correction. Some bins can disable Closed Loop enable for both, but some only turn off LTFT, so you still have STFT. Easiest way I found without disconnecting O2 sesnor and codes is set INT/STFT min and max to 128, also set BLM/LTFT min max to 128. Now you have no narrow band O2 sesnor feedback and are getting the fueling straight from VE tables. Clear BLM learn...

For the more common E10 fuel set Stoich AFR in bin set to 14.2 (close, see above) and Wide Band set for 14.2 and use Lambda which should be 1.00. 1.01 is lean and .99 is rich, .85 comes out to about right for 12.5-9 AFR for PE...

[JeepsAndGuns]

What is STFT and LTFT?

I have also have a MTX-L in my wrangler. It still the stock fuel injection/ecm. It will hold a really steady 14.6-14.8 afr 90% of the time. The rest of the time being cold start and inbetween gear changes.

But back to my cherokee. If I take the simulated NB output of the MTX-L and use that as the input for the pcm, I get a almost rock steady 14.7 afr, however after a few days I get a o2 error code. So I know this thing is capable of holding a steady afr. And like said, it held a steady afr before the switch to MPFI. So I am still wanting to think its something to do with the hack/switch to mpfi.

[RobertISaar]

STFT = Short Term Fuel Trim = INT
LTFT = Long Term = BLM

[EagleMark]

I have also have a MTX-L in my wrangler. It still the stock fuel injection/ecm. It will hold a really steady 14.6-14.8 afr 90% of the time. The rest of the time being cold start and inbetween gear changes.

Cold start is adding fuel for choke and in between gear changes is a major deceleration which would cause a rise in AFR but decel enleanment could cause lower AFR. Either way it's normal between shifts.

But back to my cherokee. If I take the simulated NB output of the MTX-L and use that as the input for the pcm, I get a almost rock steady 14.7 afr, however after a few days I get a o2 error code. So I know this thing is capable of holding a steady afr. And like said, it held a steady afr before the switch to MPFI. So I am still wanting to think its something to do with the hack/switch to mpfi.

The simulated narrow band is just a solid voltage. The signal from the ECM/PCM has a high, low and does cross counts. So two differant animals.

Why it's changing from 14.7 to 13.5 and back and forth I'm not sure? Something some where like a coolant temp adjustment to fuel, MAT & CTS Blend Multiplier vs. Airflow, Cat protection, PE or EGR, something is happening. SInce it starts at 13.5 and goes up to 14.7 it's sounds like a Lean Cruise, what was the Paremeter the 98V8S10 said could be used for that?

Or since the O2 sensor seems to cause it maybe something with it's settings? Proportional gains, switch points etc... Looking at BJYL the Rich O2, Lean O2 and RichLean switch are all the same and all low of .450. I have not had enough hands on time with this mask to know why? Normally lean is lower, rich is hagher and the rich/lean is in the middle...

Did you ever hook up the serial connection to laptop and program the LC-1? Wondering where it's set?

[EagleMark]

Ha! Got one!

Hey JeepsandGuns, why don't you post a log and we'll look for what's happening?

[JeepsAndGuns]

I dont have any currently saved. I also do not have a serial port on my laptop to reprogram the output of my MTX-L to make it work with the egr pintle position hack. So the WB afr in the log will not be correct.
I noticed when I was unhooking my old home computer, that it has a serial connector on it, so I might try and run a extension cord out to my jeep, take my moniter, mouse, and keyboard, and see if I can get it displaying right. I wont have time today, but I might have time to tomorrow. Once I get that fixed, I will make a log and post it up.

[JeepsAndGuns]

Cold start is adding fuel for choke and in between gear changes is a major deceleration which would cause a rise in AFR but decel enleanment could cause lower AFR. Either way it's normal between shifts.

Thats the point. I was simply pointing out that with the exception of cold start and gear changes, it holds a near steady and constant afr. I was showing that a veichle is not supposed to swing all over the place like my cherokee is doing.

The simulated narrow band is just a solid voltage. The signal from the ECM/PCM has a high, low and does cross counts. So two differant animals.

Not when I had mine hooked up. It would swing up and down just like the NB would, it was not a solid voltage. However, it would display a slightly differnt high and low voltage than a NB. So thinking possiably that could have been the reason for the error code? Since the mtx-l is programable, if I could find the correct voltage range and afr, I could probably reprogram it to match.

[RobertISaar]

this the 99 cherokee we're talking about? because anything OBD2 is VERY sensitive to the O2 signal. have to have the correct swing strength AND frequency for a given situation otherwise the PCM will think it's faulty. usually it takes multiple trips to set a bad O2 code as well.

[JeepsAndGuns]

this the 99 cherokee we're talking about? because anything OBD2 is VERY sensitive to the O2 signal. have to have the correct swing strength AND frequency for a given situation otherwise the PCM will think it's faulty. usually it takes multiple trips to set a bad O2 code as well.

NO NO NO! Not my 99 grand cherokee. My 79 cherokee that I am running a 7427 mpfi system on. I dont have any plans on fiddleing with my 99 WJ.
My 79 cherokee I am running a AMC 401 I converted to fuel injection. I started out with a 7747 tbi, then converted to 7427, then converted that to MPFI doing the resistor mod to the pcm and all the bin changes listed in the mpfi zip file.

[EagleMark]

Hey JeepsandGuns, why don't you post a log and we'll look for what's happening?

[JeepsAndGuns]

Keep your undies on!...lol
I finally found a affordable serial to usb adapter at office depot. I installed the driver, got it set up and installed the innovate program. Finally got the output of the mtx-l to what it should be to match the adx.
Then I noticed all my tuning logs from tuner pro (when you make a change to the bin, it makes a text document showing what you did) were changed to logworks logs and I couldnt read them anymore. So I had to go back and remove the program and change it all back...lol.

I had been fiddleing around with things for a bit and drove it to warm it up. I went for a short drive and had to cut it short and high tail it back to the house as I got the low battery warning on my laptop. It went into standby about 1 second after hit the stop recording button. Couldnt even disconnect from the pcm, just had to shut it off.

When it saved the file, it saved it as a openoffice configuration file? Hope that doesnt mess it up?
Had to wait at a stop sign a bit, and slow down for some traffic. But hopefully you can get a idea of what its doing. It would stay above and below 14.7, hardly never near it. Today it seemed to want to split its time between 13.5 and 15.
Here is my adx and a copy of my bin along with the log.

[EagleMark]

If LogWorks does that again don't worry. Just right click on any file that was converted to a LogWorks file and Properties, General and you will see Opens with. Change it to Notepad and there will be a check box for all files...

[dave w]

Here's what I came up with for WBO2 averages using the vecals spreadsheet. As a note, I was not able to use the .adx posted above. I used the attached .adx to extract the WBO2 data.

dave w

[EagleMark]

Is that with DFCO filtered out?

His wideband comes set from 7.35 to 22.39. The definition is set for 10 to 20

JeepsandGuns:
What size injectors do you have?
Where is your distributor set? Why did you take out the Main spark bias and cold spark bias and add up to 20 degrees timing? Your cruising down freeway at 40 degrees advance? Idle is 24.x Have you checked with a timing light to see... "Where is your timing really at?"
You may have a VSS issue, it went from 53 to 160 and back to 53 in about 2 seconds at 2.07 in log? And spikes again at 3.07. But it does not show as screwing with your AFR or injector duty cycle.

I'd have to say your AFR is all over the place? One thing that is driving it nuts is Decel and DFCO inbetween gears and takes some time to recover. But the only time it is really close to steady is idle or ligh cruise...

What I would do is turn of Decel Enleanment, DFCO and take 5 to 8 degrees of spark out, re data log. There still may be an issue with injector size and math...

HTH! You own me an hour looking at your logs...

[dave w]

The notes from the VECALS spreadsheet instructions.

dave w

filters applied to data:

Power Enrichment="inactive"
Acceleration Enrichment="inactive"
A/C AE Enabled="no"
Deceleration Enleanment Flag="inactive"
Deceleration Fuel Cut-Off Flag="off"
Idle Flag="off"
Idle Spark Enabled="false"

its filtering out AE (active), PE (active), anything less than 2% tps, idle ve flag (on), Dcel enlenment flag, DFCO, and idle spark flag. it leaves just the records that were recorded with no other adders active at the time.

this was built around a logfile generated by A217_0D_v250.adx writen by 93V8S10. if you are using a differnt adx make sure the following values are setup properly in the adx file, so it will export them as colum headers in the csv file: