All O2 sensors created equal?

[RobertISaar]

should be. take a multimeter in ohm-mode and see what the black wires spec out to. and that neither black wire has a connection to the blue wire.

[JeepsAndGuns]

No dice.
Swapped it in today and it still wants to stay around 13.5 AFR.
I unhooked the battery for several hours this morning to let it clear and reset. Drove it around a bit seeing it was going to start adjusting itself, but seems to want to still adjust itself to 13.5. Got my laptop and checked my blm's. All looked good, everything between 126 and 130. So I am kinda out of ideas now. What would be making it want to hold a 13.5 afr instead of 14.7?
Any chance it could be that the WB is in the right down pipe and the NB is in the left down pipe?

Also, back when I had the simulated nb output of my wb hooked up and would get the o2 sensor failure code after a few days, what are the qualifiers to set that code?

[gregs78cam]

So your BLM is saying everything is cool, but the WB is telling you otherwise? I would try to figure out which one is lying, or if there is something mechanically different between the two exhaust pipes, like maybe a leak in one? Can you put the WB in another EFI vehicle you know runs right? Or have a spare NB you know is good?

[EagleMark]

Any chance it could be that the WB is in the right down pipe and the NB is in the left down pipe?

Yup, swap them.

Also, back when I had the simulated nb output of my wb hooked up and would get the o2 sensor failure code after a few days, what are the qualifiers to set that code?

I don't know but my LC-1 WB will set it too.

Is the WB setup correctly in software? Free air calibration? Heater calibration? Is WB in data and gauge? My LC-1 is set for data 2 ways and a gauge and they all run same AFR or Lamda...

Is this $0D running MPFI? I wonder if there is an issue...

Data log? Bin? Could it be AE because of manual trans? Does PE show lower AFR?

How's it run other then that?

[JeepsAndGuns]

I did the free air calibration to the WB when I installed it. Thats the only thing that was required before installing it.
No exhaust leaks I can see or hear.
I have the WB output of it hooked up to the pcm to the egr pintle position and did the required changes according to the instructions in the XDF. Although, the output voltage of the MTX-L and what the xdf said it needed do not match perfectly, so I do not get correct reading in the data logs. I can reprogram the output of MTX-L to match, but it only came with a serieal cable, and my laptop does not have one of those ports. I just cant justify spending almost $50 for a adapter I will use only 1 time.
Could I hook the output of the MTX-L directly to my autoprom and have it display in the datalog correctly without having to reprogram it? I think I remember seeing a thread one time where you showed how to hook up a WB using the autoprom. Manual says the output is 0V=7.35 afr, and 5V=22.39 afr, so thats what its at right now.

Yes, this is on my 401 running $0D and MPFI. I followed all instructions in the zip file for the mods needed to do the MPFI swap.

Come to think of it, I do think it started all this when I went mpfi. Although I only had the WB for a short while when I had the TBI, it held a normal afr, although it would want to stay around 13.5-13.9 afr at idle only. But once I started driving it would raise up to the normal 14.7.
Ever since I swapped to MPFI, I have tried several bins, all do the same, so idk, unless its something to do with the required changes to run mpfi.

But other than the slightly rich afr, it runs great!

[EagleMark]

USB to Serial adapters are only $10 to $15...

You may need to do Free Air calibration again? There's also a heater calibration done .

Also could be a ground issue, I wire my ground to same spot as ECM ground on engine.

You can wire analog 1 yellow wire into AutoProm and a ground from AutoProm back to block where WB ground is.

Issue could also be a slight miss on WB side or injector on WB side?

2.4
Sensor Calibration

Once the unit has been wired and a suitable location has been found for both the gauge

and the sensor it is time to do the sensor calibration. Innovate Motorsports’ ‘Direct

Digital’ wideband measurement principal allows you to calibrate the sensor to

compensate for sensor wear. This procedure takes just a few moments and it will insure

the most accurate readings throughout the oxygen sensor’s life. This procedure is

required anytime a NEW oxygen sensor is installed.

The calibration procedure requires that the oxygen sensor be in
free air, not in the

exhaust. Important: Just because a vehicle is not running does not mean that the

exhaust system is free of gases.

1. With the
sensor disconnected, apply power to the MTX-L.

When power is applied, all three digits will light up and the needle bar will sweep

once through all LEDs. Then the status light will turn red and the numeric display will

read “E2”. This is an error code, indicating that no sensor is detected. Leave unit

powered on for minimum 30 seconds.

7
MTX-L_Manual.doc

2.
Power down the MTX-L and attach the oxygen sensor using the cable provided.

Again, make sure that the sensor is in
free air (not in the exhaust).

3.
Power up the MTX-L.

Again, the display should ‘sweep’, but instead of an error, the display will display

“Htr”. This indicates that the sensor is being heated up to operating temperature.

After 30-60 seconds, the display will switch from “Htr” to “CAL”, indicating that the

sensor is being calibrated. A few seconds later, your MTX-L will begin displaying

AFR. Since the sensor is in free air, the gauge will default to the upper limit of 22.4.

The calibration procedure has completed and the system is now ready for use.

Important:
You can disconnect and reconnect the sensor and sensor cable for

installation without losing your calibration. However, if you power up the MTX-L

without a sensor connected,
your calibration will be reset (see step #1 above).

2.4.1
Calibration Schedule

Normally aspirated (daily driver)

- Calibrate before installation of new sensor

- Calibrate new sensor again after 3 month of use

- Thereafter calibrate once a year or every 20,000 miles, whichever comes first

[JeepsAndGuns]

I will try the fre air calibration and see if it does any different. Its definately been longer than 3 months since I have installed it.

All 8 of the injectors were brand new when I installed them. Well, they are actually "take outs" removed from a brand new crate engine. But I guess that doesnt mean they are all perfect.
I do have everything grounded to the engine.

[JeepsAndGuns]

The following was taken from another thread talking about changes to bins for conversions.

1. Where is the O2 sensor now compared to when it was stock? How far a difference? Convert it to percent and adjust "Integrator Delay Vs. Airflow"

2. Proportional Gains vs O2 Error - "PRP - Gain vs. O2 Error" and the multiplier " PRP - Gain vs. Air Flow" need to be reduced 25% to 50% depending on cam.

Mark, those two o2 sensor comments you just posted, could that be something I may need to do? Where is the o2 in a stock 7427 vehicle?

[EagleMark]

1995 Chevy truck is way back after Y pipe, so if you have long tube headers and in collector or after collector your probably OK. This is not the norm though as most early GM EFI were in exhaust manifold or right after.

INT or Integer Delay is time it takes for PW adjustments to reach O2 sensor, when way off because of headers or conversion it can read wrong time.

[JeepsAndGuns]

1995 Chevy truck is way back after Y pipe, so if you have long tube headers and in collector or after collector your probably OK. This is not the norm though as most early GM EFI were in exhaust manifold or right after.

INT or Integer Delay is time it takes for PW adjustments to reach O2 sensor, when way off because of headers or conversion it can read wrong time.

Right now I still have the stock manifolds, the NB is probably 6-8 inches away from the outlet of the left manifold. So definately a lot closer to the engine than a stock 7427 vehicle. I dont really have a "Y" pipe per say, I have a dual in, single out magnaflow muffler. I have the pipes coming from the manifolds down past each side of the trans, then joining to the dual inlets of the muffler right behind my transfer case. They join together inside the muffler and then exit at a single 3in oulet.
So, since the NB is so much closer, do you think the delay needs adjusted? This could be the problem with my AFR?

[EagleMark]

Right now I still have the stock manifolds, the NB is probably 6-8 inches away from the outlet of the left manifold. So definately a lot closer to the engine than a stock 7427 vehicle. I dont really have a "Y" pipe per say, I have a dual in, single out magnaflow muffler. I have the pipes coming from the manifolds down past each side of the trans, then joining to the dual inlets of the muffler right behind my transfer case. They join together inside the muffler and then exit at a single 3in oulet.
So, since the NB is so much closer, do you think the delay needs adjusted? This could be the problem with my AFR?

Dont mean to hijack this thread, you can move these posts to my o2/AFR thread.

Moved posts!

I don't think so? It needs to delay so the adjusted PW is noticed by the O2 sensor before adjusting again. Since it's shorter it already see's it sooner... I don't think it's your AFR difference, but it may help to shorten the time.

[JeepsAndGuns]

I understand the need for the delay. But the more I think about it, the more its making want to think it needs adjusted. I mean, the o2 is several feet closer to the engine than a stock 7427 vehicle, and if the pcm is using a delay set up for a far off o2, and mines close, it might be taking readings from the wrong time frame?
Maybe I am just completely misunderstanding it.

[EagleMark]

I think your understanding correct. Just don't think's it's your AFR difference issue.

[JeepsAndGuns]

Free air calibration of the WB did not change anything.
It seems after a few days of running the new sensor, it is now running 14.7 half the time, and 13.5 the other half. It just seems to have a mind of its own, with no rime or reason for what afr it wants to run. I have closed loop idle, however its always 13.5, no if ands or buts (unless its at a cold start). Then once driving, it will run 14.7 for a while, then 13.5, then 14.7, then 13.5. Makes no sense to me. I did a datalog last weekend trying to see if there was anything else that was happening at the different afr's, thinking maybe it was one afr at this map range, and another afr at a different map range. From what I saw map did not appear to make a difference. I could find nothing.

I still keep wanting to think it could be the mpfi and that this is a hack/modded tbi pcm. I also cant help but keep wondering what a 7730/$8D would do with this engine? Seeing as how its a factory mpfi ecm.

[dave w]

I've worked on tuning a couple WBO2 TBI systems. The logs below are from a 95 Tahoe. I've noticed a difference in the WBO2 data after BLM update is disabled, the AFR's are more consistent! The log below was done after BLM update was disabled. The Tahoe is using a heated NB and a WBO2 in the exhaust system. For all practical purposes, the NB is keeping any error codes from occuring. The VE table is adjusted to the WBO2. I think it would be a worth while experiment to disable BLM update and and tweek the VE tables to see if the AFR's can be tuned to 14.7?

The vecals.zip makes WBO2 tuning a '7424 extremely easy! It's well worth the time to learn and use the Access spreadsheet!!!!!! I use the vecals spreadsheet to extract the near idle / off idle WBO2 history tables only. I then copy / paste the Access WBO2 history tables into my VE Excel spreadsheet to make adjustments to the '7427 VE tables.

dave w