ddub

Glad I could help, better safe than sorry right? For all those people that believe the Mazda OEM solution to apex seal lubrication is the best, premix mearly gives you added protection.

NZConvertible

The sheer ignorance in this statement is unbelievable...

Wrong. All engines (piston and rotary) need a thin coating of oil on the cylinder or chamber walls to lubricate the moving parts. It's common knowledge that the richer the AFR is the thinner this oil film will be, because the excess fuel washes it off the walls. It doesn't matter how you introduce that lubricating oil, the effect of rich mixtures will be the same.

ddub

Ignorance? Far from it, sir. From all the people I've talked to that run narrowband AFR gauges in many different cars, and all the talk and experiences I've read on various car forums, no one has every had very good experiences with narrowband. The best they ever get out of them are during WOT or climbing steep hills and putting more load on the car.

I've even read many other forums that have dubbed the Autometer AFR gauge as nothing more than a "rainbow gauge" or "blinky light display" because of how crappy they work.

While driving/cruising at normal speeds all I see my AFR gauge doing is bouncing back and forth erratically, only when I floor it or go up a steep hill does it really slow down and peg itself at a certain ratio.

Please enlighten me, then, of why I am so ignorant.

hondahater

iTrader: (2)

well the reason it is going back and forth is because its in closed loop at that time however when you gun it thats when I'm supposing its giving you your reading however I've never had it do anything besides peg the most rich point on the gauge.

ddub

Well the reason you're always pegged at the rich is probably because the "rich" range is from about 10.3 to 11.8 as far as a ratio. So since you're probably running really rich, being untuned, you're most likely in this range, which would make sense.

And yes I understand why it does that during cruise and such, but that still convinces me how crappy narrowband really is. I'd rather have, and will soon, a wideband gauge that can tell me my real AFR during any kind of driving, whether it be cruise or WOT.

Mx6-Rx7 Addict

Aggreed.. i'm in the process of purchasing the Innovate Wideband (hopefully)

Plus the ability to datalog is such a good thing to have.. (Wolf3d doesnt support yet )


-Justin

hondahater

iTrader: (2)

I agree with you! I really don't like narrow bands either! I would way rather have a wideband and hopefully will get one soon. On the 7 before and after all the mods I've always had a narrow band and that thing always pegs the rich side I'm assuming because its always dead rich.

NZConvertible

I'm afraid your comments prove you have no idea what you're looking at when watching a narrow-band AFR gauge, and hence probably don't understand what your engine is doing. All the threads you've read are obviously from people with the same limited knowledge (I've read several of them myself).

If you have even some knowledge of how EFI works you'll know that the AFR is constantly changing to reflect the conditions the engine is under. This means that every time you move your right foot, the AFR will change. You said, "Unless you are at WOT or going up a steep hill it will just bounce all over the place." No ****! That's because that's exactly what the AFR is doing. Put you foot down, the mixture gets richer; lift your foot up, it gets leaner. Close the throttle completely and the display goes blank because the injectors are turned off. Then under constant light-load cruise
the ECU rapidly swings the AFR back and forth around stoimchiometric for the best low-emissions conditions. This is what you'll see on the AFR gauge.

If you've kept up, hopefully you'll realise any wideband display should show you exactly the same thing. The only difference between the two is accuracy under load and resolution. But this doesn't change what the ECU is actually doing with mixtures, and that's the bit you and many others seem oblivious of.

The fact that you singled out AutoMeter AFR gauges proves further ignorance, since all narrow-band AFR gauges are simply LED voltmeters that use the same circuit and work exactly the same. Saying one or more accurate than the other is nonsense.

So displaying exactly what is actually happening in the engine makes a gauge crappy? Jeez, you're hard to please...

Anybody who uses the words "blinky light display" should not be giving anyone else advice on how to monitor and modify EFI systems.

ddub

No it wont show exactly the same thing!

The narrowband AFR gauge, like the Autometer Z series that I will be referring to, has lean/stoich/rich settings, right? Well the Lean range is from 0.050 to 0.249 volts which is ~19.1 to 14.7 AFR, then for the stoich range its from 0.250 to 0.749 which is ~14.7 AFR, and then the rich range is 0.750 to 1.000 which is ~13.2 to 10.3. Now I understand a little variation can happen with AFR's when cruising and lightling pressing or letting off the gas, this is a no brainer! But when my gauge flashes from full on lean to full on rich and sometimes stopping in between (but normally flashing from lean to rich constantly) when I am holding the throttle relatively in the same place keeping the same revs and going the same speed this just doesn't seem right. Are you trying to tell me that it is accurate in that it is going from about 11.0 to 18ish AFR just by cruising? I'm sorry but that is a load of crap!

When I see wideband units in WOT or cruising in cars it is much different. For example in a normal cruising the AFR might range about 1 or 2, maybe 3 at most, but no more than that. My narrowband gauge is sweeping a difference of about 6-7 just cruising. The only time I can get the gauge to be relatively stead or at least only sweeping within one of the ranges (lean/stoich/rich) is when I am going up a steep hill or at WOT. Otherwise I have these humongous sweeps that are just a little too hard to believe.

You make it sound like the narrowband units are so great. Fine you can believe that, but then what is the point of wideband units if these narrowbands are showing EXACTLY what the engine is doing? I mean **** if it's so great then they should just stop producing wideband units all together shouldn't they?

RETed

This is why you premix.


-Ted

NZConvertible

This is what I mean about not understanding what the gauge is showing you. For starters, you will not get accurate AFR numbers off a narrow-band gauge, so if your gauge has them then you should be ignoring them. Only someone who did not understand the characteristics of narrow-band sensors would take them seriously (or quote them). All you're seeing is the voltage generated by the sensor, from 0-1V. Stoichiometric is right about the middle (it's a point, not a range). All the display does is show exactly what the sensor is reading, and it can react far quicker that the wide-band sensors. What you're seeing with a wide-band is simply an average reading of a short time period.

If you want to tune accurately, you need a wide-band, there's no disputing that. Experienced tuners can and do use narrow-band ones, but I doubt any here could. But you haven't mentioned accuracy once, all you've complained about is that the reading moves about a lot. Well guess what? That's because it's supposed to! It's attitudes like yours that made manufacturers switch from linear temp gauges (S4) to 3-position cold/normal/hot ones (S5), because they "moved too much". A narrow-band gauge is an excellent engine monitoring tool because any change in gauge behavior almost certainly means a problem somewhere.

Because of widespread ignorance about how narrow-band sensors work, and some terrible marketing by suppliers, these gauges have been bought by people for completely wrong reasons. But if you say they're "useless" just because you can't tune from them, it just shows you don't understand what it can be used for.

pengarufoo

NZ is essentially right here, but I suspect ddub is just having some communication issues rather than not understanding what is going on with the narrow band.

just look at your narrow band driven af gauge as a gauge with 3 positions. rich, stoic, and lean.

This information is useful, so if you have no wideband, but can easily get narrow band information, it's better than nothing! The problem with the narrow band is if the AFR goes in the direction of rich or lean from stoic, the gauge will swing to that extreme. I personally think it is a fault of the gauge manufacturers to present this data with an array of LED's that suggests a linear relationship to the AFR's.

You can certainly get your tune reasonably good with a narrow band, I mean, at least it can tell you one of 3 things about your mixture. It's rich, lean, or stoic <grin>.

hondahater

iTrader: (2)

so if I press on the gas peddle and its pegging the rich side if i just take some points off of my safc it should not peg the most rich light but should be somewher in the middle of the rich array?

pengarufoo

Kindof, more like, pull fuel until you get it where it starts to go to stoic, then look at the difference in fuel (where you started and where you are now) and you can approximate how much fuel you have to put back in to get somewhere between stoic and very rich, err on the rich side with a boosted motor especially when you are tuning heavy load into boost.

I found this narrow band o2 sensor curve graphic via google, it should help with understanding why your a/f gauge is not as useflu as one with a wideband connected to it:


Notice how the middle of the graph, has a vertical line spanning a large range of the total voltage. Roughly half of the sensors voltage range represents the same lambda value (1). This leaves roughly a quarter of it's range available for the ranges lean through stoic, and stoic through rich. Knowing this, it is clear that the sensors resolution and overall usability for measuring the areas from rich to stoic, and stoic through to lean, is extremely compromised. Look at the curve on both sides of stoic, a very minor voltage change reflects a major change in lambda.

So, to use a narrow band for tuning you have to use a slower process and use the af gauge as an indicator when you've reached stoic... and by knowing the injector duration when it was very lean or very rich, and what it is when you've reached stoic, you can come up with a difference in the duration and with that knowledge get a rough idea of how much to put back or remove from the duration you are messing with to get where you want the afr to be.

make sense? It's not perfect, but it works well enough, you will get more familiar with it as you do it more. Also, if you are going to try tuning your car remember to make small individual changes at a time, if a change doesnt get you closer to where you want to be, undo it before making more. And always remember to pay attention to what the engine is doing... don't get too fixated with the gauges, above all pay attention to what is really going on under the hood, keep ears open for detonation etc. Even if your AF gauge tells you everythings exactly how you want it but the engine is running like **** but wasnt before, go back to the old setting and take a step back, look at the data, and come up with a plan. Sometimes you will find that even though the AFR is perfect you have something else you need to change to make it run well at that AFR, like the timing at that load cell.

Also, don't tune WOT / heavy boost yet. Start with tuning cruise and idle, the in-vacuum regions, get that all down especially since you are new to it, these areas are much safer to mess with... and these are what will have the greatest effect on your gas mileage and drivability. With a boosted rotary you will probably be targetting relatively rich AFR's under WOT in boost anyways, so leave it alone up there for now... unless it's so rich you're leaving trails of black/brown fuel smoke.

good luck.


- edit

I forgot to mention, when you press the gas pedal, there is more at work than just the base fuel maps with temperature corrections applied. During the actual pressing of the throttle, your throttle pump values are referenced and applied to the base fuel maps to enrich the mixture when you open the throttle (similar to an accelerator pump on a carb). So at first you want to just tune steady states, don't fixate on spikes/dips in AFR's when the throttle is moving at first. Once you get the base maps close enough that the steady states are all pretty good then start looking at the throttle pump values if you get rich spikes when you press the gas.

The haltech manual has some helpful pointers on all this also, I have this AEM manual online which is a pretty good resource for tuning EFI too:
http://pengaru.com/downloads/aem/AEM...asics_V1.3.pdf
some of it is AEM-specific but most of it applies to programmable EFI in general.

I just realizd you have a safc, the information I provided above is assuming you have programmable engine management like a haltech or aem standalone, but it still applies when you are tuning the safc, you just don't have as much resolution and control.

teknics

iTrader: (4)

im sorry but thats hilarious. take your foot off the gas pedal...which only controls the amount of air being introduced (which the ecu reads and then decides the amount of fuel)...and the injectors TURN OFF? LMAO!

that's great so when your foot is off the gas pedal there's no more combustion happening at all in your engine? HAHA.

kevin.

eViLRotor

iTrader: (2)

Sounds to me like he's talking about deceleration fuel cut.

fc313bt88

im not pushin autometer afr but in my 88 t2 mine never went into closed loop it always had a af readin not that it was 100% true but it sit on the last 2 yellow lights and would get richer as rpms were raised i dont know why it worked like that but i liked it that way the ricers around here have them and mine didnt do the same as theirs that was a good thing i hate ricers

Aaron Cake

iTrader: (1)

Funny eh? Too bad it's completely true. During decel, fuel is cut from the engine. Fuel is reintroduced at the engine approaches idle speed...

Net Seven

iTrader: (5)

I dont agree with you, because as you increase the fuel, the amount of oil is also increased. I could understand where aaron was comming from if you have the stock OMP then yes, you dont get extra oil with the extra fuel. I think your just making some statement just to argue. I see you doing this kind of crap a lot, just to argue with people.

What difference is there if you got a bunch of gas and a bunch of oil or little gas and little oil? If the ratio of oil/fuel was the same, there would be no difference. Premix is mixed with the gas, its not just sitting there chillin on the walls all seperate then the big bad fuel comes and washes it all off. Yes I know the metal parts get coated with it, but as the amount of fuel increases the amount of premix oil is also there to back it up.

Conclusion

Your statment makes no sense.

Net Seven

iTrader: (5)

So NZConvertible, here is another person that agrees with me.

NZConvertible

You should learn to check your facts before laughing at people who know a lot more than you do. Fuel cut on decel is a feature on just about every EFI system made in the last 25 years. It's controlled by the throttle position sensor, which should give you a clue as to how it works. Perhaps you should spend a little time learning a bit about EFI before your next insightful post...

Correct. Why would you want combustion when you lift your foot off? You're trying to slow down aren't you?

You guys need to realise that LED mixture meters are extremely simple devices. All they do is display the O2 sensor's output voltage. 0V from the sensor means no LED's lit; 1V means all LED's lit. They are so simple there's very little that can go wrong with them. This means that if you're getting odd readings, either the sensor is old and needs replacing, or (gasp!) something is wrong with your car.

It's the ECU that goes into closed loop, not the gauge, and if it doesn't it's a clear indication that something in the car needs attention. It's not a problem with the gauge. If your temp gauge starts to show abnormally high readings, do you assume the gauge must be crappy and just ignore it? I hope not...

So theirs were displaying correct operating patterns, and yours was indicating a problem. How is this is a good thing?

You have a very good point, but that still doesn't make rich mixtures a good idea. I am quite certain that even with premix engine wear will be higher. Why take the risk?

Yeah, I don't care if I'm right or wrong, I just wanna argue with somebody... Dude, that's a truly dumb thing to think. If you don't like people disagreeing with you, don't post in forums.

hondahater

iTrader: (2)

so in the end just get the ****** tuned I'll just try to keep the car in the garage or at least at low boost until I tune it. Thanks guys.

eViLRotor

iTrader: (2)

^Exactly. Took us 4 pages to come back to square one: Get it Tuned!

Good thread though

hondahater

iTrader: (2)

lol, I'm a slow learner