AFR at idle

[G-E]

wow I missed another few pages of arguments.... I hope they were good

as always crowbar you seriously have to stop behaving in an accusing manner, most of your posts are fact-free and merely state irrelevant things like the machinery you use and principles that you fancy

seriously like jason and many of us have said, post data without commenting on it first, let us discuss it a bit and then join in with your conclusions, or to correct any assumptions of methodology on anyone's part

no one will have an argument over measurements, only the conjecture surrounding it

[crowbar]

Seriously. Where did you go to school? Seriously.

no one will have an argument over measurements, only the conjecture surrounding it :idea:

This is the single funniest thing I have read in all of your rambling posts.

I work for a company that distributes and services some of the most accurate test equipment available. we provide calibration of those items also. We are accredited to 17025.

I will make that statement my new mantra. I truly and honestly would like to know what that statement means to you.

seriously like jason and many of us have said, post data without commenting on it first, let us discuss it a bit and then join in with your conclusions, or to correct any assumptions of methodology on anyone's part

Gee. A review by my peers? Is that what Sup did? he posted data and people discussed it without knowing his methodology? What method is that called? Its bs. And Jason did not say post 'data'. Stop putting words in other peoples mouths.

[OR-Zman]

You could have asked me...asking someone else just isnt good form. :?

How pretentious to think that I would have deleted your thread without sharing it with the other "Trolls". I am hurt...well...ok...not really. :x
Here it is for all to enjoy:

A simple test to determine the AFR at idle is the following:

1. Warm up car and set RPM to 2000 rpm
2. Access the ecu LED output signals
3. Using accurate DMM, measure the O2 sensor signal voltage when ecu mixture mode LEDs are flashing in unison. This is mode 2 for 5 mode ecus (87+). A good calibrated DMM with min/max feature will typically show 0.45 volts with min and max hovering about that reading.
4. Return car to idle and let idle a few minutes
5. Measure the O2 voltage at idle. Compare to previous reading.

If the voltage is below the reading from step 3, its obviously leaner at idle. If greater than, than its richer.

Since the ecu does not change the timing at idle (when warmed up), it is just using the MAF reading to meter in the fuel. If the MAF was not very constant, the idle would also oscillate about a rpm reading.
_________________
no one will have an argument over measurements, only the conjecture surrounding it -GE

Now...explain how that is even useful and how you came up with this "test" method. If it works Im sure several of us would love to know the details behind it.

[G-E]

crowbar wrote:

no one will have an argument over measurements, only the conjecture surrounding it

:idea:

This is the single funniest thing I have read in all of your rambling posts.

I work for a company that distributes and services some of the most accurate test equipment available. we provide calibration of those items also. We are accredited to 17025.

I will make that statement my new mantra. I truly and honestly would like to know what that statement means to you.

there you go again proving my point, you love to spew stuff about yourself, but even when you're specifically asked for actual data you go and start insulting people

oh and btw since you're a bit slow, absolutely none of your posts in this thread have contained data, all they say is "do X if you want to see Y" except that doing it wouldn't give you the data you claim it will, and it has been pointed out why not.... and you haven't even addressed that counterclaim, instead you poopoo everyone else

[crowbar]

How pretentious to think that I would have deleted your thread without sharing it with the other "Trolls". I am hurt...well...ok...not really.

I just assumed you deleted the post/thread since you did harrass me with unsolicited PMs such as..

Your ignorance and ability to argue about nothing is actually quite appalling.

Know this. If it were up to me you would have already been banned. This board doesn't need your brand of BS.

From a troll to a shit fly....you are fighting a losing battle.

But I am going to let that go (even though I suspect you are lying). Jason already said he will deal with Steve88T and I hope he deals with you also. You abuse your position as moderator. And you are a poor moderator as this very thread shows.

GE: You are probably suffering from some thinking disorder. I am not saying that to be insulting. I actually mean it.

You are going on about 'data' with no conception of methodology or precision about taking said 'data'. You have the cart in front of the horse and its just another indication that you are lacking in a means of using rational thought patterns.

I am not the only one that has told you something like this. I am sure you have heard it from others.

[crowbar]

For those of you that use logic and reasoning in their daily lives, I would like to explain the following:

A simple test to determine the AFR at idle is the following:

1. Warm up car and set RPM to 2000 rpm (car in neatral)
2. Access the ecu LED output signals
3. Using accurate DMM, measure the O2 sensor signal voltage when ecu mixture mode LEDs are flashing in unison. This is mode 2 for 5 mode ecus (87+). A good calibrated DMM with min/max feature will typically show 0.45 volts with min and max hovering about that reading.
4. Return car to idle and let idle a few minutes
5. Measure the O2 voltage at idle. Compare to previous reading.

If the voltage is below the reading from step 3, its obviously leaner at idle. If greater than, than its richer.

Since the ecu does not change the timing at idle (when warmed up), it is just using the MAF reading to meter in the fuel. If the MAF was not very constant, the idle would also oscillate about a rpm reading.

My car has passed emissions recently and I know from daily use it gets great mileage and starts and runs great. I can say with some assurance that it is in a calibrated state. My digital multimeter is also calibrated and highly accurate also.

Since the cars own BIT (Built In Test), the LEDs, also show that it passes the 2000 rpm test, we can take that state to give us a very good indication of what the O2 sensor output shows at a stoiciometric condition.

In the case of a closed loop car, this is actually a 'dithering' process whereby the single known good point (14.7:1) is constantly crossed over. Its actually called a cross-over datum point and the a quality factor for O2 sensors is the frequency of cross-over events.

By using the multimeter in min/max mode; I can capture the avg voltage at this state and also the high and low. Typically avg should be 0.45 volts and high and low0.6 and 0.3 volts respectively. I am doing that from memory but its about right.

By using the frequency option on the multimeter, I can also qualify the crossover events too. I would actually use my oscilloscope to be honest.

This data collected from a calibrated vehicle and test equipment can then show us what the car is doing at idle.

My car does not flash LEDs at idle when the TPS shows the car to be at idle. I do not believe it is in closed loop. I believe the car is in a state of feed-forward control that is basically looking at the MAF signal. I would speculate it could even be closing the loop around RPM or CHTS or combination of many .

In any case, doing the measurement above WILL show you if the car is lean or rich at idle (which was the point of the first post in this thread). I am assuming that the car is in a fully warmed up condition and there is no temperature extreme outside such as arctic weather. It is entirely possible that the car may actually be 'standing' at stoic and not dithering while in the idle condition. I wouldn't bet on it but it would be interesting to know. I doubt a car would idle around 16:1 or so because of the NOx pollution but a very low voltage may actually indicate that.

O2 sensors can vary greatly outside the stoiciometric range depending on the actual operating temperature of the sensor itself. This condition is worse for richer than it is for leaner. But within the stoic range it is fairly accurate.

[crowbar]

Jason84NA2T wrote: I think I can sum this entire thread up pretty simply:

1. Post warmup, the timing maps for idle and timing at the cells at idle speed in the main map are both the same. Hence, if the engine is warm and at idle, TIMING will be the same in either TPS position. Both also should have the same AFR which IS closed loop at idle when the engine is warm. Whoop, AFR at idle should be around stoich if closed loop is active with a good O2 sensor.

2. Most narrowband sensors, even when brand new, don't cycle fast enough for smooth and unfluctuating AFR at idle if the fueling is very much different from what they (nissan/jecs) calibrated. This is the one way titania sensors are superior; faster feedback. They also don't have the resolution you would need to measure AFR's very far from 14.7, but they ARE accurate right around 14.7 so they can be used for diagnosis at the very least. You would not need a zirc wide spectrum (AKA wideband) sensor for this.
.

1. I am not so sure about closed loop around idle. My test would prove that out wouldn't it?

2. Titania are faster? Can you post any info on that? Its a cross-over response actually. How fast the ecu and O2 can work together to cycle about a value.

[G-E]

crowbar wrote: 2. Titania are faster? Can you post any info on that? Its a cross-over response actually. How fast the ecu and O2 can work together to cycle about a value.
you weren't talking about measuring the ecu, or were you? no I'm pretty sure you didn't so the above is more of your trifling combativeness

crowbar wrote: By using the multimeter in min/max mode; I can capture the avg voltage at this state and also the high and low. Typically avg should be 0.45 volts and high and low0.6 and 0.3 volts respectively. I am doing that from memory but its about right.

by using an ngk o2 sensor poster hanging at my mechanic I can deduce that .9 volts is the highest they go and .45 is dead smack in the middle and they show you a neat line graph for the responsiveness range, oh but I didn't need super precise testing equipment to read it so it must be wrong

[crowbar]

Yes, arguing with irrational people, that use posters in garages as datasheets, is an exercise in futility.

[Chris86NA2T]

this is the most wasteful post ever!! what a stupid topic to spend time on.. crowbar, you should have posted:

"hi guys.. i wasted a bunch of time looking at flashing lights and unplugging sensors in a very scientific manner. I collected data that is completly useless.. hell, its not even interesting. many of my conclusions are simply wrong.. I just thought i would post it and then make strange arguments with people so i have the opportunity to bring up my job and try to brag about how smart i am, even though all i do each and every day is confirm measurments."

fuck off crowbar, you pathetic waste of life.

[crowbar]

I was hoping someone would step up and prove me wrong. Unfortunately, you stepped up and showed yourself to be not only a feeble comedian, but an obscene one.

[G-E]

Chris86NA2T wrote: this is the most wasteful post ever!! what a stupid topic to spend time on.. crowbar, you should have posted:

"hi guys.. i wasted a bunch of time looking at flashing lights and unplugging sensors in a very scientific manner. I collected data that is completly useless.. hell, its not even interesting. many of my conclusions are simply wrong.. I just thought i would post it and then make strange arguments with people so i have the opportunity to bring up my job and try to brag about how smart i am, even though all i do each and every day is confirm measurments."

fuck off crowbar, you pathetic waste of life.

hahah, I think that about sums it up

[SupSay Z]

crowbar wrote

Sup

Please show how you measured the afr. You mention 14.7:1 and then 14.5:1? Do you have some sort of wideband system? Is the origional O2 sensor still present or gone (replaced by something else). Do you have a good reason to believe you have an accurate system?

this is measured with a wideband LM1 unit.

[crowbar]

Is this that Innovate product? I assume you 'calibrate' this to the procedure in its pdf manual?

I reviewed that and any product that goes into a calibration procedure, and does not call out specs on its product is questionable.

The resolution of the LM1 is 0.1 of AFR. Can anyone tell me the accuracy spec for this product (assuming a proper calibration)? They should really give a steady state and dynamic accuracy spec by the way. They should also give a drift over time spec but its already clear from reading the pdf that the owner must 'calibrate' this device often.

I would always keep a narrow-band O2 sensor in my car if using one of these wide-bands. It allows you to do a quick sanity check on the output of the wide-band around 14.7:1 ratio. The cheap narrow band does this very well.

[Jason84NA2T]

O2 feedback is enabled at idle in the ecu programming. I still don't understand exactly what you are trying to say/prove.

crowbar wrote: The resolution of the LM1 is 0.1 of AFR. Can anyone tell me the accuracy spec for this product (assuming a proper calibration)? They should really give a steady state and dynamic accuracy spec by the way. They should also give a drift over time spec but its already clear from reading the pdf that the owner must 'calibrate' this device often.

I believe it is also a claimed .1 AFR accuracy.

They do not require "regular" free-air calibration, I've only had to do mine three or four times since I have owned it (minus when I changed sensors).