A Blue Lude

How will the oxygen content "match the indicated MAP readings"? MAP (plus engine speed) describes airflow. Oxygen content describes air-fuel ratio.


[QUOTE=DCFIVER;43661015]Haha, I see you went and studied up on the subject. Should have done that before you made the first ridiculous post about fuel trim. But it is appearant that you are still not totally clear on the subject. 1 and 0 are the maximum numbers and will likely never be seen by the ECU. So fuel trim is not based on that. Lambda cannot be determined by oxygen content alone. Fuel trim is also not based on that. Keep researching....

There was nothing ridiculous about the first post (notice I didn't say "fuel trim", either). It captures the same content as extended version. Except with out all the acroynms that you feel you need to use to seem....knowledgeable? And no, I didn't need to go and research that...maybe for the SPX BAR 97....my ECU doesn't spit out a data channel with that heading.

Did you see the "≈" symbols in the post? The ones that are not the same as "="? A narrowband output will approach but usually not equal 0 and 1v. As I'm sure you're familiar with the output form of a narrowband sensor, you'll no doubt agree that precise (forum?) measurement of narrowband voltage isn't really a big deal....it's either on the "rich side" or "lean side".

By the way, you might want to let Google and the manufactures know about that - they seem to call exhaust gas sensors that measure (only) oxygen content "lambda sensors". They also seem to be good enough for the auto industry to use in a whole lot of vehicles.


Wow, I never knew engines were so fast. What a revelation. http://www.youtube.com/watch?v=8-ymU7ETnnY

You're pushing your luck - sure you get valves open at the start/end of strokes (intake open after BDC at the end of the intake stroke for high RPM power, intake and exhaust open at the same time, blah blah), but the exhaust stroke is not dominated by the intake valve being open. Not in the Prelude forum, with our nice external EGR systems, anyway.

But hey, why don't we go all Atkinson cycle and have the intake valve be open for much of the compression stroke too?


Yeah, but one "EGA" isn't going to measure all the cylinders, individually, at the same time, is it? Unless you have the super acronym version and cut some holes in the exhaust manifold. Maybe you do.

How much HP can your dynamometer absorb. The ones I use can probably do better. But you never know.

mgags7

thats nuts never knew the valves were prone to spinning around like that

A Blue Lude

(And even if you say you can pick up an increase in NOx, say, at load, through the cat, and attribute it to one cylinder, that's not something an oxygen sensor will notice and account for)

DCFIVER

[QUOTE=A Blue Lude;43668376]How will the oxygen content "match the indicated MAP readings"? MAP (plus engine speed) describes airflow. Oxygen content describes air-fuel ratio.


Really? Your previous post regarding fuel trim was the most incorrect, laughable information I've seen in a long time. The fact that you found a web site that taught you better the second time around doesnt change your first RIDICULOUS post about fuel trim.


Wrong. Which just goes to show how information on the net can be misleading and if you do not know what you are talking about you can easily look foolish.

Again an innstance where the information can be misleading or in your case, misinterpeted. Just because it is refered to as a Lambda senor does not mean it measures Lambda. Knowing what you are talking about is key here stud and you are failing...





Siggggggh. You really need to take a class. So little understanding going on here....




You continue to speak on subjects you have absolutely no clue about. An EGA is one of thee most useful of diagnostic tools. just stop dude.
Forget it. Look, this can go on forever. I will keep shooting down the inaccurate or partial information you find on the web. Face it, you havent a clue. Youre trying to save face but the information you are coming up with falls short.
Heres the bottom line: CAN A VACCUM LEAK ON A SPEED DENSITY SYSTEM CAUSE A LEAN CONDITION, YES OR NO? I said yes it can. If you disagree, youre an idiot, plain and simple. And so far you have been disagreeing. Im done here.

DCFIVER

Yes, that is one of the reason the keepers become worn out.

A Blue Lude

My first post is pretty much how these ECUs work. I'm sorry. Maybe you should pick up some more experience with them? Stuff like "and oxygen content must match the indicated MAP readings or the ECU will determine something is wrong and set a MAP code." suggests that you don't know what's going on. The ECU barely knows the oxygen content of the exhaust - only if it is more or less than a stoichiometric burn. If it remains stuck on one side of stoichometric at the limit of the O2 sensor's authority then you'll get a CEL but it probably won't be for MAP.

What's wrong? The output shape is correct. In practical operation it means the narrowband only outputs two values: "rich" and "lean", around the 0 and 1 v areas. This is really basic stuff.

No, it measures oxygen content. And they're used in applications where Lambda needs to be measured. Perhaps you should go tell Honda, et al, that they're doing it all wrong? Something that measures Lambda accurately would make such a difference.

I never said it wasn't. Anyone I've ever spoken to who tunes with a multi-gas sensor will rave about it, and trash oxygen sensors. Not nearly as cheap though.

A vac leak at the plenum will not cause a lean condition. A vac leak at the intake port could potentially cause higher than expected airflow to that cylinder. It will also cause a reduction in manifold vacuum (see earlier discussion about how the engine is only sucking air approximately 1/4 of time). I could see it splitting both ways.

You incorrectly state that an O2 sensor (in the conventional collector based location) will adjust for this. The same "average" measurement of manifold pressure that you claim occurs (and causes a lean condition) will also work against the oxygen sensor. If cylinders 1-3 are at Lambda = 1 and #4 is at Lambda = 1.2, the O2 sensor will not see 1.2.

q16racer

you do know we are referencing OBD1 code right? It's not that smart, hence the reason its code was easily broken....

mgags7

I said valves because I imagined that the valves, keepers, springs, and retainers were all spinning as one unit. Is that not true?

DCFIVER

Your killing me kid. i hate to respond but I hate to send you away thinking you are right. You'll never learn that way.An O2 sensor has a range of around 16:5-13:5 This is THE ONLY source of feedback for the ECU to determine oxygen. What happens to the exhaust stream in the event of a vac leak?? What happens to MAP readings in the event of a vac leak??



So basic that you dont even understand what you are looking at. The graph is showing you the MAXIMUM operating range of the O2. There is a TON of information in that graph that appearantly is over your head. It DOES NOT hover around 1 and 0. An o2 sensor in a healthy OBD1 engine will hover around 450mv. Thats the operating window. No where near 1 or 0. If it starts to approach either of those points then there is something wrong. Thats basic!! Any kid fresh out of tech school can tell you that. It just kills me how you act like you know, when you dont know ****!!



More stupidity. Lambda is not a "thing" to be measured. Lambda is a formula. Thats one of the ways i know youre full of ****. If a guy comes on this forum claiming to be an expert in the VTECH system ,you would know instantly that he was lying just by the way he spelled VTEC. You are using the word Lambda in the incorrect context because you do not understand it.



[/QUOTE]I never said it wasn't. Anyone I've ever spoken to who tunes with a multi-gas sensor will rave about it, and trash oxygen sensors. Not nearly as cheap though.[/QUOTE]



I never said a plenum leak would cause a lean condition. I clearly stated a runner or gasket leak. And you said it would not cause a lean condition. Are you back tracking now??

Wrooooong.(And its not Lambda=1, its just Lambda.) It will see the increase in oxygen content. Where do you think this oxygen goes. It just dissapears?? It will increase the stoich mixture and the ECU will try to adjust causing the other 3 holes to be rich, but you will still get a lean code.

DCFIVER

And you want me to tell Honda they are wrong? You tell Honda they are wrong. Because I learned this **** from Honda 7 years ago, while youre just now trying to catch up. (These are pictures of some of my old training material)

DCFIVER

I understand, but the ECU is still more intelligent than you give it credit for. Even back then it was capable of making instant adjustments to sensor inputs. The O2 sensor's rise time alone was 100 milliseconds.

DCFIVER

Yes but imagine the strain on a keeper when a valve is both oscillating and bouncing.

DCFIVER

I'll save you the trouble of trying to find the Lambda formula. You probably wont find it. Im seriously done teaching here. Suffice it to say that whatever information you dig up to retort with is probably wrong like most of the info you have posted so far. Take a class dude.

Training and instruction>internet wisdom.

q16racer

your not teaching anything. just spouting off.

LUDEcidDream

whats an 02 sensor













just kiddin

DCFIVER

No, Im correcting the nonsense that you and blue lude are spouting off. Hacks with no true understanding of what they are doing, getting by on dumb luck and trial and error....

d112crzy

Holy ****, so much senseless bickering in this thread.

DCFIVER is correct in just about everything he has said. But what he doesn't realize, or doesn't think about, is that all the scenarios that he's throwing out hardly ever happen to an already tuned motor and/or aren't drastic enough to cause damage.

If you get tuned, it is because your motor is in perfectly running condition. You're not going to get a random vacuum leak at the intake gasket on an already put together motor. If you do, the change in afr isn't going to be drastic enough to cause damage.

A stock narrowband will only try to adjust to stoich. I've put a wideband on at least 10 difference cars with functioning o2 sensors. ALL of them ran richer than 14.0 at all times.

A vac leak WILL cause a lean condition. SO WHAT?! The motor can't possibly suck in enough air through such a small orifice that will cause a motor to blow. If for some reason there is a vac leak large enough to cause more than a 1.0afr change, then the narrowband will add fuel until it see's an average. Adding of the fuel will cause higher EGT's and probably cause more long term damage than a slight lean condition will.

There is absolutely little to nothing that an o2 sensor can adjust for that you can't adjust for in numerous compensation tables in the tuning softwares. If your motor is going to blow, a narrowband sure as hell won't save it.

I built an h23vtec that I put nearly 50k miles on. I always ran it in open loop without ANY issues. I ran it in 0* weather and 100* weather. I had to make slight adjustments to my compensation tables for both conditions, but that's it. I always had great idle afrs and averaged 35mpg in the city. I recently took it apart due to oil starvation issues, but the pistons had an awesome burn pattern.

Also, 16:1 afr on an 9.0 compression motor is MUCH more safe than it is on a 12:1. As long as there is no det., who gives.

Car companies try and get all their motors running to stoich because it is the best compromise for power/emissions/economy. Not because it IS the best afr to run at period. Hell, MBT is no where near that and neither is best economy.

I, like Blake, leave the ecu in open loop after I tune. The ONLY time I disable open loop is when I'm burning a basemap for someone and/or they live/are moving to a location where altitude/climate changes.

DCFIVER

The scenarios are not unlikely given the age of the motors we are talking about. Any scenario is possible. Does every owner replace their gaskets with new ones?Does every owner put in brand new fuel injectors?? Brand new manifolds?? The whole point of my post was "why risk it?" A vac leak that is causing a hole to run lean will cause damage. That is a fact. How long it takes before this damage occurs is up in the air. But will the owner have any indication that they have a vac leak?? Are there any indicators that you leave in that will alert the owner that they have a lean condition. An O2 will catch it, and set a code. So why remove it? Replace it with an AF sensor if neccesary,but why remove the feedback. Its there for more than emissions. That is a common misconception.

Im a professional repair tech, but I also modify and have had my car tuned.(Whitfield Racing and Churches) Thats why Im on this board. Ive been modding my cars since 1992. I still do. (A DC5 now) So I can appreciate the subject from both sides of the fence. Like I told Q16, if it has been working for you, then I will never get you to change your ways. Just interjecting a different perspective.

A Blue Lude

Yeah, they're oxygen sensors - absolutely - they detect oxygen content.

And are used by car companies to calculate lambda. This is not a debatable point either. Emission controlled cars need to run at about lambda = 1 (on a variety of fuels) to pass emissions. Oxygen sensors are used to accomplish this.

You can get to lambda by measuring excess air (like an oxygen sensor does). It won't be able to tell you about the fuel you're running (ie, supplying those variables that appear on both sides of the division line in your posted formula, and as such don't really matter), or even tell you your air fuel ratio. But it will be able to give you the ratio of your AFR to the stoichometric AFR.

If you've used a wideband you'll know you actually have to plug in the stoichiometric AFR of the fuel you're using if you want it to give you AFR.

Sound like motors where something isn't functioning right. Or arn't warmed up, or are at high load. Seriously. If the car can't get to stoich and has the O2 sensor on it will throw a CEL to tell you something's broken.

A Blue Lude

And the typical automotive sensor's output is voltage against lambda...so calling them "lambda sensors" as well as "oxygen sensors" is fair, if one so chooses.