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Help with building your Speeduino, installing it, getting it to run etc.
By Black Knight
#40898
Narrow Band O2 sensor can tune nicely.

Just some back ground on what I have done over the years.

I have been tuning cars before there was an O2 sensor.

I am so glad that they were invented because they sure help with good tuning. I have been using NB O2 since the early 1990s.
I have tuned mechanical injection systems with them
(k jetronics) All types of carbs including propane. NB O2 has worked very well using a voltmeter.

Now I just got into ECU building ten months ago. So far I find them very fun and good to work with.

Then I kept reading that NB O2 cannot tune correctly yet I have been using NB O2 for nearly thirty years.
So I set out to find out what was the truth.
How can it work for 30 years and now they don’t work on ECUs?

I can get volt readings from 1.2v down to minus .7 volts with an NB.

Then I get to the point where I am calibrating my NB O2 on TS and it just fell off and gave no readings on TS below .4 v.
So I set out to find out why.

This lead me to need to learn about electronics. I took readings of both volts and amps of the NB O2. The volts were there but the amps drop off very quickly around .4v. So I concluded the O2 is just fine and it had something to do with the ECU.

It is the forward voltage or voltage drop of the ECU making the NB O2 not work. Mostly.

Now I was on a mission to beat this problem.

I got a good WB O2 and a good NB O2 and set up a test.
I created a controller that could work with the NB O2 and use a friends WB O2 for a comparison.
I like the WB. It works very well. But I was still on a mission to get the NB to work. So lots of learning of electronics and hard work I got the NB to start to give a wide range of volts/AFR to TS.
I finally got both NB and WB calibrated to work well and liked both.

But with all I had done on this test I should finish the NB controller and it’s calibration to see what it really could do.
In the end the WB can be more accurate in the extreme rich and lean areas but they are in AFRs that we don’t need.
Just to be clear. I like both WB and NB now.
My NB can show on TS and MLV as lean as 23 afr and as rich as 7 afr and will tune correctly with in about .5 afr of target AFR.

I set my NB on the controller to 11 afr and 20 afr because any more is not needed. On my NA economy car I set the controller to 12 afr and 18 afr. With that and setting up the calibration on TS to match tuning is much easier.

In conclusion I find WB just slightly better at the extremes but the NB is cheaper and less likely to have an internal heater to fail.
I have an NB that is 25 years old and it still works and is accurate.

I like both and can tune well with both so you will get no conflict from me.

I have now got both calibrated dead on and both now have dead on lambda delay set up with my new way of finding delay.

I am new to this and find all of it fascinating and fun when it is not being frustrating.

Just sharing.

Hope it helps someone.

Thanks to all here I can now install, configure, calibrate, base tune set up and road tune and hand tune.

There is much more to this and it would be hard to find the words to make the test work clear on a forum.

I will try to answer questions if I can, but understand I am new to ECUs, electronics and just started tuning 2 months ago, so I may not have all the lingo yet to say it right. I will do my best.

Thanks

Black Knight
By noisymime
#40899
Whilst I won't ever knock someone's preferences if you like working with NBs, there are very good technical reasons why they shouldn't really be used for actual tuning. In (very) short terms, NB sensors are only accurate around their set point, typically 14.7:1. Either side of this point, not only are they extremely non-linear in their response, but the response curve varies greatly with temperature, sensor condition etc.
nb_sensor_output.jpg
nb_sensor_output.jpg (17 KiB) Viewed 2311 times
If you look at a typical NB response curve like this, you've got roughly 0.25v between 12:1 and 14.7:1, which is an area that is critical for tuning. 0.25v fed through a 10-bit ADC gives just 51 points of resolution, which is then scaled down in Speeduino by 2, so just 25 increments. IMHO 51 (let alone 25) is insufficient resolution points to tune a such critical area, and that is even before you account for noise, sensor variation etc.

For contrast, a (near) linear response WB controller might give a range of 10:1 to 20:1, which in the same 10-bit ADC gives you more than 5x as many points of resolution over that same 12:1 to 14.7:1 range.
By Black Knight
#40900
Thanks much for the response.

I have seen all this data and get the point behind it.

I am not trying to push one O2 over another. My main objective is to set an accurate base tune so auto tune is as good as it can be.
So far so good.

Just sharing that the NB may be more capable than the data on the Internet is claiming.

With my NB controller I am seeing stable AFRs way beyond that table above. Yes temp is important, very. That is true for all O2s.

The data on the TS O2 log file shows something very different than the Internet chart with my controller but shows somthing quite similar with out it.

Just to be clear. I am not in favor of one O2 over the other. I just had some fun making the NB work. Just a project.

I am a little shocked that it did work at all.

By all the info on the net it should not be working.

So perhaps the data is off, or perhaps I stumbled on to something that made it work better. Who knows.

I will enjoy testing both NB and WB until the truth proves out.
Just a hobby in the journey of learning ECU tuning.

Until I prove it out I will always confirm my tune by using a WB.

I have done road tunes with both and not seeing a great difference. WB is a little easier.

Before my controller was used NB was a pain in the ***.
Twitchy and unpredictable. Just like all the info says.
So I would agree that by itself NB is not so good.


It is more important to get things like the list below right.

Voltage correction
Dead time
O2 calibration dead on
Delay time
Sensor filters
All sensor calibration

And all the other things that make the tune work right, done first and as accurate as possible.

I really do want to thank you all for starting this Speeduino project as I am really enjoying what I can do with it.

I will always test the limits of what is possible so I can learn more.

I think the reply by noisymime is a good one and a good warning that until other wise proven go with the safe and proven way.

There are enough challenges with ECU install, calibration, and tuning with out going off the proven path.

Thanks to all again.

Listen to noisymime.

Black Knight
By Black Knight
#41050
I wanted to post this sooner to show that noisymime is correct, I just found this graph in my files.

This chart is close to what I am finding with typical NB O2 sensors.

I have slightly better readings in the rich AFR area than this chart, but the rest is close.
I don't have the twitch O2 problem of the typical NB because of the controller I built.
I was having a problem with my set up because it would get stuck in the lean AFR below
19.5 AFR. I fixed that with my controller. As I don't need any thing leaner I made it so the controller
will not send that voltage/AFR range to the ECU. No more sticking. I can now get to 20 AFR with out sticking and as rich as 9 AFR.


I just started to set up an EGT sensor that can record EGT data when driving and tuning on TS and MLV.

Should be done in a few days. Calibration will be the fun part.

I can use EGT to log the data so I can create my own AFR to temp chart so I can soon see if I am making the NB O2 work better.

It is tuning very nice now but I want the EGT and O2 proof in MLV data.

Now that I have the O2 calibration dead on and the lambda delay dead on, tuning is hitting AFR target more than good enough.

I was setting the O2 calibration as little as .1 AFR change and could see the tune swing slightly lean or slightly rich. Not enough to harm the tune, just good to learn it can be that close. Delay has a big impact on this also.

I am looking forward to the EGT being done then I can see another sensor to verify the tune.

Finally I am learning how to use my old school tuning ways with the new school ECUs.

This is a lot of fun when it is not frustrating.

HEHEHE

Black Knight
Attachments
02 sensor best chart.png
02 sensor best chart.png (98.41 KiB) Viewed 2153 times
By 126p
#41051
Hi,
Could you share the details of your controller (for example a schema or the source you based your design on)?
I used self-made LED display with NB to tune carbs with good results, so I'm curious of your design.
I see that you are using NB with heater, right? I'm curious what would be the difference for NB without it?
By Black Knight
#41059
126p wrote:
Fri Feb 21, 2020 8:39 am
Hi,
Could you share the details of your controller (for example a schema or the source you based your design on)?
I used self-made LED display with NB to tune carbs with good results, so I'm curious of your design.
I see that you are using NB with heater, right? I'm curious what would be the difference for NB without it?

All good questions. Thanks.

My controller is sending the data directly to the O2 pin out on the mega board ECU. My gauge is the one you see in TS. I can also see the data on MLV as a normal O2 sensor. I could add a gauge to the signal wire if I wanted but TS is just fine. I can also send the data to shadow dash of TS.

I use my O2 and EGT for tuning on TS and MLV.

My controller is amplifying the weak signal areas and filtering extreme lean data so the auto tune has less aggressive swings. This helps it tune more accurately. It also compensates for the voltage drop of the ECU of about .4v and that was the reason the lean signal of NB O2 will not work well.

As to the O2 heater. I have tried both. GM single wire from TBI and a 3 wire.

In short. Temp really is important. There are three ways to make this happen.

One is use a heated O2.

One is insulate the exhaust pipe and O2 to keep the heat in.

One is move the O2 to a location in the exhaust to get the correct temp.

You can over heat the O2 so location should be a little cooler than best temp and then use insulation to get it right. Just play with this and you will see the O2 start to work better.
This is true for WB also. WB heaters are much better than NB but if you help retain the heat you will stress the heater less and have less heater fails.

Both are connected to an ECU and to TS for logging so I can see if it is correct.

I am just now creating an EGT controller so I can find the best location and/or verify the tune with the EGT.

My O2 is in the factory location now at 30 inches away from exhaust port and I did insulate the exhaust and O2 and it is a heated O2. The response and range of the AFR was greatly improved. Then my controller took over and all looks very good now.

As for tuning for carbs. I just learned to tune in volts not AFR. The volts are more correct because there is no conversion math or circuit to possibly give data that may be off. Volts is volts. The issue is that NB will shift quickly when you get close to a good AFR. They tend to get stuck on the lean end and also on the rich end. So when they start to fluctuate around your preferred AFR it would be time to look at EGT for back up data.

Also what helps for carb tuning is an O2 sensor extension socket to retain some heat and slow the reaction down some so you can read the volt meter. $6 on ebay?

I have tuned gas and propane carbs this way both NA and turbo. It works and well.

It should be possible to use a mega board and a controller to see the O2 and EGT on TS for carb tuning. Then you will have data logs. This is what my bench test is. It is set up to only read the O2 sensor and nothing else. Soon EGT will be logged. So I can view the data and make changes later. Picture seeing your AFR about every .5 seconds. It can even show if your accelerator pump is going lean or rich.

So, maybe the question should be. When will I have a set up for carb tuning that logs on TS and MLV? Very soon I think. I wish I had one a long time ago.

As for the schematics and design of my controller. I learned electronics this year and created my own set up and I have no idea if my idea has been done before. It is still under testing for long term dependability.
I have been daily driving with it for over a month now. No issues at all.

Keep the questions coming, it helps me remember things I am starting to forget.

Thanks

Black Knight.
By dazq
#41062
If you wanted some help getting going with firmware , take a look at my gpio mini or std firmwares, these take analog or digital signals and allow them to be viewed or logged in TS. You can also use the logical outputs for other things if that's needed. Details can be found on the wiki under third party boards.
By Black Knight
#41065
dazq wrote:
Fri Feb 21, 2020 11:54 pm
If you wanted some help getting going with firmware , take a look at my gpio mini or std firmwares, these take analog or digital signals and allow them to be viewed or logged in TS. You can also use the logical outputs for other things if that's needed. Details can be found on the wiki under third party boards.


Thanks.

I have seen you postings before. I will take a closer look at what you are sharing.
I can always learn more and I need to.

I will be needing to learn more about the firmware soon. Good point on your part.

I should have the EGT working on TS with in two days.
I just got the 0mv to 50mv converted to 0v to 5v.
Now to set the volts and TS config to show true temps in f deg.

When the volt conversion is correct and the calibration is correct I may need to set up the firmware soon.

Once again, Much thanks.

Black Knight
By Black Knight
#41066
126p wrote:
Fri Feb 21, 2020 8:39 am
Hi,
Could you share the details of your controller (for example a schema or the source you based your design on)?
I used self-made LED display with NB to tune carbs with good results, so I'm curious of your design.
I see that you are using NB with heater, right? I'm curious what would be the difference for NB without it?

I have been thinking about your posting all day.

I am glad you asked the questions you did. I have been working on setting up to run my cars with an ECU and did not stop to think that most of what I have done so far could be a good carb tuning system.

I have a crank sensor circuit that can work with VR and Hall and dizy signals.
I have an O2 sensor circuit that works with NB.
I have a simple set up for MAP sensors.

All are connected to the mega board just for testing them.

So, maybe I should put them all together and make a carb tuning set up.

RPM, Load/MAP, O2 and EGT showing on TS and MLV would make a good tuning tool for carbs???

What do you think?

Thanks for helping my look up and outside the ECU bubble I have been in.

Black Knight
By Black Knight
#41107
I got the EGT bench test done.

Propane into an exhaust pipe that has both EGT and O2 in it.

EGT is recording on TS and MLV.

EGT to controller to mega to laptop works great.

It is calibrated to show the correct deg f in MLV.

Next is to test what happens with change of AFR to see how EGT reacts in a car.

I have done this with carb tuning and volt meters but data logging the info is way way better.

Now I need to set up a circuit to install in the running car and road test this set up.

I can also test the exhaust temp to O2 reaction. I have seen and shared the graphs on this sight that I found on the web and now I can test and share what I find about O2 and temps. So far the charts on the web look incorrect from what I saw yesterday. I will know soon.

I think I will start a new thread on EGT now I have one working. I can also share why they are good as an aid to tuning soon.

Black Knight
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