lean burn rules~!
 

Hey,
So I'm in this Meteorology class and we’re talking about emissions related to cars and how the industry controls them through catalytic converters and burning of fuels. This guy says in class, I got lean burn on my car and how does it affect emissions? I was like; whoa...I haven't heard anyone talk about lean burn from anyone ever. I was like, yea I got lean burn too but we didn't mention what car we had lean burn. This guy looks like a hippie or a computer engineer of some sort (very smart guy) so I figured he put in lean burn himself which we did the same on my car. So class ends and we talk. He said his 1993 civic VX came with lean burn but was from Oregon. I told him about our lean burn which was incorporated through coding he was like, Wow! So anyways long story short, I start researching about the civic VX because California loves to raise high gas prices. I was reading but I could not find any threads that explained lean burn in terms how swappable or ease of swap from California’s ECU to a federal ECU.

So my questions are
Is lean burn only federal ECU’s?

Can I buy a California Civic VX with a D15Z motor and put a Lean Burn ECU in it?

If so which ECU’s come with Lean burn and how do I Identify it?

Is the lean burn code on a PROM style chip? Can I take the “bin” file and place it on a EEPROM and it’ll work in a California Civic VX? (Easy to make chips as I do this for my other car)

If it were able to burn a chip what else would I need to do on a California car to go into lean burn mode?

What is the easiest way for me to go about this process as I live in California but want a Civic VX with lean burn?

Cheers
Cool wHip ~ stewie griffen

There's more to lean burn than just the ECU. The actual engine is able to get the most out of lean mixtures. I know that the HX is effectively a SOHC motor at low RPMs, and opens up the other four at higher RPMs. As for the VX, I have no idea. Not to say that you can't lean out any engine, you can, but you won't get the same results. I've got a mild lean-burn mod on my Cavalier, and it seems to give maximum benefit at around 16:1 AFR. Much leaner than that, and economy actually drops. Parts of the fuel mixture actually get too lean to burn.

Just like the VX/HX, I needed a wideband sensor to do this. You'll also have to install one to get a reliable lean burn. At this point, you can go for the VX/HX ECU (if all the sensors are compatible), or you can fashion a circuit that will train the stock ECU around an AFR of your liking. It's easier to pass state inspection this way. Just crank her back to 14.7:1 and she passes with flying colors.

I laughed when I read new user: CoolwHip. Funny, funny. Ever since seeing that, it's one of those words that's etched in my head ... in somebody else's voice. Go figure.

I can't really offer any more info than JohnnyGrey has, but there are a couple other VX owners who may chime in.

that word whip , does that evolve from when we use to have to crack the whip to start the horses?

JohnnyGrey- i would like to learn how to lean out my gas engines when I am not loading them heavy. On a '91F250 302 for example the ECU is not reprogrammable is it? I did a brute force lean burn by putting a 0 to 10 ohms reostat in series with the injector pwr. And as I dial in more resistance the voltage to the injectors decreases, the ECU tries to compensate but evenually the 02 voltage starts dropping and I can get it down to 0.24 volts and the engine will still run. This is not a wide band 02. comparing your wide band to a stock sensor, if you had to quess how lean do you think I am. i am going to try it with a different mileage computer as the one I am using reads injector pulse width which of course gets wider as the ECU tries to compensate for low voltage.

Modulating the injectors in this fashion probably won't give you consistant results. They're "on/off" devices, so by supplying low voltages, the cylinder to cylinder spray pattern and volume could vary considerably. As long as your car is in closed loop mode, there's no point in attempting mods like this since the ECU will compensate as far as it will go, then throw a CEL fit.

Your narrowband sensor is a poor indicator of AFR. Treat it like a digital signal, where >0.45v is rich and <.45v is lean. What actual voltage you get will vary with each sensor, exhaust temperature, ECU bias voltage etc, so there's no real way to know. Plus, if the voltage stayed at .24 for long, that's probably the voltage floor of the signal. It indicates a lean mixture, but there's no way to say how lean you were running.

A wideband lets you do so much more. Mine is made by Bosch and the driving unit is made by AEM. It puts out 0-5v which represents linearly ratios from 11:0.1 to 18:0.1. The driving unit also has a narrowband emulation mode that does switch back and forth over that .45v point at 14:7.1. This is fine if you want to run at that ratio, but we don't.

So we need a box that puts out either 0v or 1v depending on whether or not that 0-5v wideband signal has crossed a certain threshold. If the switch point is set at 4v, the motor will run quite lean (around 16:1), but the ECU will believe it's running at a steady 14.7:1 and will not throw a CEL. Also, it will be training itself around that ratio, and will hold it steadier than you could in open loop mode.

With a narrowband sensor, you're working blindfolded. The hot rod guys prefer to tune with widebands, but in a pinch, they can tune with a narrowband. Their only concern is running rich so nothing blows up, so as long as the O2 reads high and the engine sounds happy, everything is fine. For economy though, you need tight control over the AFR.

As to whether or not the ECU in your truck is programmable, I would say not for closed loop operation, and we're not interested in the open loop tables, they're for WOT operation. Also, I doubt Ford would implement a lean burn system since it is not emissions legal. I have no idea how Honda got away with it in the HX/VX.

It is technically possible for an ECU to run a lean burn on an engine equipped only with a narrowband sensor. In fact, that's exactly what GM does on cars it sells outside the US. That narrowband sensor is only good for switching around 14.7:1, so the ECU establishes fuel tables for that mixture. Once you get on the highway, the ECU goes into lean burn mode, which is actually open loop. Since the ECU already has a well-established fuel table that produces mixtures very close to 14.7:1, it can scale that table to produce whatever fuel mixture it needs. For example, 92% to run at 16:1. Because the narrowband sensor will read consistantly lean, the ECU occasionally wanders back to 14.7:1 to confirm that its tables are correct, then goes back into lean burn mode. On US ECUs, the mode is disabled.

I am definitely in open loop. I know the injectors should be either on or off but there must be a gray area there because it doesn't seem to be a knives edge. Maybe they open slow and part way open and I only do it when cruising at steady state. Yeah who knows about the cylinder to cylinder variation without an 02 in each exhaust header. Well i could do 8 channels of temperature, i guess.
Without being able to program the ECU maybe i would be better off reducing the fuel pump voltage and therefore the fuel pressure to force the mixture lean. The ECU can't deviate more than 10% or so from the fuel tables can it? This old truck is speed/density, bank injection. Obviously I would like to able to see and control pulse width. What is my alternative get some kind of after market programmable fuel management system. Staying in open loop and being able to the adjust the offset from theoretical 14.7 would be cool.

The VX engine (d15z1) is the same anywhere in the world, as far as I know. People have swapped in JDM d15z1's and registered them successfully in CA.

The only difference is the O2 wire and ECU. The CA model uses a 4-wire narrow band O2 sensor while the Federal model uses a 5-wire wide-band (which is $$$). I believe the Federal ECU is the P07 model. Unlike most other Honda ECU's, it cannot be modded.

On GS, one member made the sensor/ECU swap on his VX and still easily passed his CA smog inspection. For those who care, NOx can be partially dealt with through a NOx adsorber as used on the Insight. The Insight entered lean-burn much less often (and less aggressively) and purged the adsorber through enrichment, but its basic operation would transfer over to a VX.

Most OEM lean-burn engines that I've seen increase charge turbulence and/or use a specially crowned piston to concentrate the gasses. Honda partially closes one intake valve per cylinder to improve what they call "swirl."

Extensively recirculating exhaust gasses accomplishes the same goal as a lean-burn engine without the emissions issues.

You can probably build a MegaSquirt (w/ sensors) for $100-200 and gain much wider control over your engine. While it would cost more, I think it would be more worthwhile than tricking your ECU into lean burn. Just a thought...

- LostCause

If you're sure the motor will work, do the Federal ECU swap. The 4-wire sensor is a dead giveaway that the CA model doesn't support lean burn.

I'd imagine this absorber "purging" process cancels any benefit from burning lean.

John, how are you certain you're in open loop, is the O2 unplugged? I tried doing this on my Cavalier, but the variation in AFR was too wild to run reliably for any length of time. I would advise against slowing down your pump. If it produces less pressure than the regulator needs to open, the fuel supply line will slow to a crawl and the return line will stop. Depending on the design of your pump, it may be cooled by the fuel that runs past it, which will not be much if you go below regulator pressure. Try finding an adjustable fuel pressure regulator instead.

Be careful if you do this, because you will have leaned out your WOT mixture as well. If you need a sudden burst of acceleration, you could cause severe detonation. My car stays in closed loop at around 16.5:1, but if I stomp it, open loop is still around 12.5:1, so I can still get full power out of my engine safely.

JohnnyGrey, I would like to get into tuning these injected gasoline engines. What is a good direction to head so I don't have redundant equipment? What is the fifth wire on a wide band, temperature? I assume the other four are heater pwr, heater grnd, signal, signal grnd.

I'll look up this MegaSquirt.

The extra wire is bias current. There is no easy way to hook up and monitor the sensor alone. You need either a gauge or a controller box to drive it. Or you can look at Bosch's data sheet for it and try to make your own.

I'm new here but I think I'll jump in.

cool: "Can I buy a California Civic VX with a D15Z motor and put a Lean Burn ECU in it?"

Yes. I did precisely that, with the car I drive daily. But I don't live in CA.

I think it's been mentioned that you also need to swap the O2 sensor.

In a thread at GS (http://www.gassavers.org/showthread.php?t=4389) I provided very detailed instructions for how to do the wiring without cutting any of your stock wiring.

Unless you also swap the instrument pod, you'll still be missing the SIL (shift indicator light) that was provided only on the Federal model, but there's probably not much reason to care about that.

"What is the easiest way for me to go about this process as I live in California but want a Civic VX with lean burn? "

You might find that the easiest solution is to 'import' a Federal VX from outside CA. Finding a clean VX will be hard, and the first nice one you find might be elsewhere, anyway.

lost: "On GS, one member made the sensor/ECU swap on his VX and still easily passed his CA smog inspection."

I wonder if the comment you're thinking of is this:

http://www.gassavers.org/showpost.ph...5&postcount=43

That situation is a little different than what you described. Anyway, if you can find the thread you're talking about, that would interest me.

diesel: "What is the fifth wire on a wide band"

It might be interesting to notice that the so-called five-wire wideband sensor actually uses an 8-pin connector, and 7 of those pins are used. Two pins are attached to a calibration resistor that is housed in the connector itself. That's why you see only 5 wires traveling from the connector to the sensor.

You can find lots of info about wideband sensors if you google L1H1. The first link that comes up is especially helpful:

http://www.techedge.com.au/vehicle/wbo2/wbntk.htm

Thanks very informative looks like about $250 for the DIY wide band kit.

Ah, i see now wide band looks for hydro carbons on the rich side and oxygen on the lean side.

"looks like about $250 for the DIY wide band kit."

Sounds about right. The sensor itself is more than that, via the dealer or other typical channels, but they can be found in places like eBay for $150-200.

Then again, maybe the best way to buy a wideband sensor is with a VX already wrapped around it! I recently paid a lot for an L1H1, but it came with a free VX.

Welcome to the forum, monroe.

Feel like posting a garage entry? http://forum.ecomodder.com/emgarage.php?do=add

I like AEM's Uego 6-in-1 sensor/gauge combo. I have one in my Cavalier and I'm putting another in my Porsche. You should be able to get them under $260.

metro, thanks for the welcome, and the invitation. This place is great.

I will probably get my car into the garage at some point, but I think I want to wait until I develop more of a gaslog, and more consistency. Lately results are erratic, because I'm trying a bunch of different weird tweaks and tests, in the car and in my driving. I haven't had it very long.

Last count I had twelve P07 ECUs on hand. While they can be modified there has been no actual development on them, so they are effectively paperweights. I drop the OBD1 ECU plugs off of them and use them to make pass-through harnesses for various reasons.

Any of the OBD1 Civic/Integra ECUs, except the VX/P07, can be used with any of the common aftermarket enthusiast widebands to make a leanburn system.

JohnnyGrey, I understand you like your AEM UEGO and are excited about it. I understand you identify the AEM brand name with quality. I would advise you, however, not to recommend the AEM UEGO to anyone in the future; I have seen multiple AEM units that were as much as a point +/- out of calibration with 2-3 other widebands connected to the same vehicle. They aren't a good product. FYI, best bang for the buck is the NGK AFX followed by either Innovate (robust, programmable, a little finicky and requires free air recalibration on occaision) or PLX (dead nuts simple).

Also, I have had variable results out of the Techedge products in the past, and having to ship the wideband off to OZ to be warrantied is annoying. I currently have a 2A0, needs the SMT DAC replaced, and a 2C0, used once and then it died still looks brand new, if anyone wants to buy a DIY project...

AEM claims accuracy of +/- 0.1 AFR, which is line with what you're saying. I consider it to be an acceptable degree of accuracy, especially since the ECU swings back and forth about 1.0AFR constantly.

i think he is saying + or - 1.0 out of spec.

"they are effectively paperweights"

They show up on eBay every now and then, and pretty consistently go for about $80. I think the buyers are typically people who have a CA VX and want to make it Federal. That's exactly the situation I was in. Too bad I didn't know you were giving them away!

I unplugged the 02 signal from the ECU but still monitor it with my DVM. seems to be leaning much better now. still throws my mileage computer for a loop, cause it uses pulse width to calculate fuel flow. but it was off anyway cause i don't think it counts miles when the injector pwr is cut during engine braking.

That's interesting.

Not all vehicles run correctly with O2 sensor unplugged; some ECU interpret this as a full lean condition (0 volts on the O2 signal line) and start dumping in fuel. Poor mpg and trailerhitching @ cruise are the usual symptoms.

Most ECUs aren't completely stupid and they will only believe the "lean" condition for so long before they ignore the O2, throw a CEL and switch to open loop.

Ford trucks were a bit primitive yet in the early 90's and really until the 4.6L modulars came along. They definitely need a tow fuel map and an economy fuel map. That mega squirt looks like a lot of fun to me.

Interesting side note, when I am running along steady state, O2 unplugged, and I dial in more in series resistance with the injectors, I can get the O2 voltage to drop down between 0.2v and 0.1v. But at that same resistance setting if I go to WOT the O2 voltage still goes up to 0.8v. So at steady state the ECU cannot compensate for low injector voltage but at WOT it can.

Megasquirts either work well, or have issues.

I am currently having issues with the manner in which Megasquirt controls coil dwell w/ the TFI ignition. Defaulting to 50% duty on the coil signal results in misfiring 4000+ rpms, completely poopy. The Ford intake and coolant temp sensors are not supported by default and if you are paying for the modifications run ~$140 extra for the hardware modifications needed, and then the idle control motor's cold/warm duty cycle routine ends up incorrectly handled so there *is* no idle control.

IMO convert to 89-93 MAF from a Mustang, using one of the A9L ECUs. You can fiddle to your heart's content via the J3 port, Moates.net and TunerproRT are the things you need to check out on that.

Thanks for the warning.
i'll check it out the A9L.

If you have a honda, can we just use an Air Fuel Controller, like an Apexi S-AFC?

Identifying the 49 state vs the Ca VX Ecu
 

[QUOTE=Joseph Davis;25837]Last count I had twelve P07 ECUs on hand. While they can be modified there has been no actual development on them, so they are effectively paperweights. I drop the OBD1 ECU plugs off of them and use them to make pass-through harnesses for various reasons.

Hi,

Is there a way to identify the CA ECU by numbers? I have a '95 VX and I'm sure is a California car with 4 wire O2 and the car's book is in a California dealer folder. But if I look for the 49 state Ecu, how can I be sure I have the right one, as mine says P07?

Thanks,
Scott

Probably. I don't know off the top of my head, though.

The last three digits of the ECU part number would tell all, though.

VX ECU numbers - The Leanburn Quest
 

Hi,

I did more digging and found the answer, so I'll post it here.

ECU for 49 state:
37820-p07-a01

Calif:
37820-p07-l02

I know there are many threads about making leanburn happen in a Calif. emission car but I'm kind of boggled when I read that there are several adaptors to make the 4-wire car into a 5-wire care, while others I've read say "add one wire, but make sure it's shielded" to the 4-wire loom.

I have lots of electronic experience and don't mind tackling the project, but don't really want to have to do more head-scratching than necessary.

If someone can summarize the simplest solution, I'm welcome to suggestions.

Thanks!
Scott

Odd. I was thinking about this today, wondering if I could either trick my ECU into thinking it was at 14.7 when it was really at 16, or if I could run open loop at cruise, and reset the fuel tables to produce a 16:1 ratio? Maybe my PSC-1 could do it... From what I read here, and in other forums, a wide-band is pretty much a necessity.

No, a wideband isn't needed for daily operation. Only for the initial tune on the vehicle. Narrowband O2's are actually very accurate away from stoich; but their curve is logarithmic, a low amplitude analog signal prone to being molested by ground ofsets, and their calibration varies with sensor temperature. Run a heated four wire sensor a little ways down the exhaust stream so engine heat doesn't molest it - approx where the driver's feet are on a distributor Honda is fine - and make sure you keep the sensor's power and signal grounds seperate until they finally reach the block which is THE ground point in a car's electrical system. Chassis grounds are garbage.

I've been doing a mini engine R&D project with a friend, putting the 01-05 D17 cranks into earlier D16 engines. There's a lot of misinformation about the reliability of this combo resulting in few people doing this combo - it's mostly kids who don't know how to build an engine messing things up.

Anyway, 9:1 static CR 1.7 stroked D16Z6 1991 RT4WD wagon with an Evo8 turbo and Siemens Deka 500cc (at 43.5 psi, aka 04-05 SRT-4 injectors). Part throttle maps were tuned for 15.5-16:1 AFRs, and runs a (fresh!) stock O2 sensor whose lean/rich switch point has been set to 0.39 volts. The combo makes 185 whp at 7.5 psi and 235 whp at 12.5 psi, uncorrected figures. In 4WD, some spirited driving, 32 mpg. In 2WD, normal driving, 43-44mpg. Wagons are heavy and aerodynamic bricks, 4WD/AWD drivetrain loss is appreciable, and the air is thin as well as the land not flat up here on the mountain.

A third of the gains are tuning the vehicle. A third of the gains are having a working O2 sensor with a lowered switch point. A third of the gains are having a modern pencil core injector that atomizes far far better than earlier injectors. I've also spent a number of hours on the dyno placing the ignition event at the optimum point for all NA loads and speeds under 4000 rpms, as lean burn doesn't accomplish as much if the ignition timing doesn't place peak combustion pressure accurately at the "sweet spot" where the rod has best mechanical leverage against the crank.

This is about the most sense I have head on this site. What injectors are you using? Injector dynamics are very good and are all balanced within 5% of each other in any given set.

Are you tuning each individual cylinder according to EGTs or for overall advantage. The ID injectors will make this real simple as the RC injector in the past were not as linear. The IDs also work real well at high pressure around 100PSI to def atomize the fuel.

I am under the impression that no motor actually runs @ 14.7:1 as that would be unrealistic. I would assume you could get around 15:1 or 16:1 with almost no load on the engine. Throttle tip in would reduce the ignition in milli seconds and allow the injectors to richen the mixture to allow for acceleration with more timing.

In some programs on the Hondas you can allow the dwell angle in the distributor to accumulate more spark energy in the coil to help a more efficient burn with out having to fork out for an ignition system that would allow more sparks over a certain amount of degrees of rotation.

Injector Dynamics 1000 and FIC 900 are Bosch injectors modified to 880cc. As stated before, I am using the black/blue tip Siemens Deka cores used on the 04-05 SRT-4.

Flow balance, as it has been marketed to you, is only important with aftermarket modified cores. Most of these cores flow a certain amount in a raw fashion, and are then restricted by one or more precisely manufactured tips that are crimped or seam welded in place. These aftermarket modified units are flow match at 3% duty in the 2000-4000 rpm range, and again at 85% duty, for the sole purpose of good idle characteristics.

A 5% discrepancy at idle in an OEM injector of the last decade would likely not pass emissions. Most of these modified pencil cores would be unacceptable to any OEM in the last decade.



EGTs are for determining if there is a mechanical problem with the engine. The only time I'd do that are SBF in the 1400+ whp range as they have heat issues and are prone to thermal imbalance, despite which people still love them and insist on building them, so that's what you do. None of which has anything to do with a mild 200whp per liter street car, or for part throttle fuel efficiency.

Individual cylinder fuel and ignition trims, however, are vital for any performance tune. Those are best based off of the nature and condition of the carbon coat on top of the piston, and EGTs would not correctly reflect this. EGTs express the heat any one cylinder sheds, and not the heat that is absorbed and dealt with by any one cylinder. Much like octane, EGTs are not what people think.

All of this is entirely outside the realm of a FE tune, which would not require individual cylinder trims or temperature monitoring. Such things are largely a waste of time on a car like that. A highway cruise requires 12-18whp. Not to be hurtfully sarcastic, but oh no such power can hardly be contained?


You're talking about a huge power turbo car injector? 1000cc/min at 43.5 psi comes out as a stream and not a mist, at 100 psi and commeasurate increase in flow the bottom line atomization isn't significantly better. Not enough to make a FE related post in a FE forum about it, although the performance guys might like to hear that they have perks past smooth idle and big flow at big pressure.

For a 300-350 whp street car, I'll stick to the smaller pencil cores. Everything about them is better with regard to flow balance (irrelevant at the present technology level, unless you are an OEM appeasing the EPA/DOT) and especially FE.


Depending on the motor configuration, and injector atomization, 15.8-17.4:1 indicated AFRs is the tip over point where combustion pressures fall off. I ran an old D15B7 around at 16:1 part throttle and 13.9-14.2:1 WOT, you could feel the O2 sensor switch point at cruise as a slight surge. With the 12.5:1 D16Y5 I was in the 17's at a cruise and 13.0's WOT and it got much better efficiency due to quench/etc, despite the sportier gearing, with no closed loop surge, as well as better mpgs at all loads and speeds while making twice the power.


No, it doesn't work that way. I was the guy with the oscilloscope who tested that for eCtune, it was never correctly implemented. With 13.75-14.25 volts available you can only charge any given coil so much. Any particular design coil's inductive reactance, however, will require a different charge time at any given frequency (rpm) than another design coil will. That table is there to add a little bit more dwell to MSD Blaster2/SS coils in the 3000-6000 rpm range so that they function as well as a fresh OEM coil does - and due to the confusion I've passively advocated removing that table. There's no free lunch, at the end of the day performance cars need an ignition amplifier to get the job done. Conventional spark ignitions are very crude, and either the air/fuel mix lights or it doesn't. For low power FE setups, not worth thinking about.

Also, you want one spark, precisely timed, not multiple ones. That's another advertising campaign, thanks a bunch MSD.

I heard running the car without the O2 hooked up is very bad for the O2. I heard that since it is suppose to be heated by its heater ciurcuit, when its unplugged, its not getting this, and the hot exhaust gases can ruin it.

Maybe this is wrong, but i'd read up on this before continuing to do that.

Where do you get that I'm doing anything of the sort?

Right from this sentence in the post I quoted from you.

"Not all vehicles run correctly with O2 sensor unplugged"

That would lead me to believe you are running the car without the O2 hooked up. Maybe you took the O2 completely off the exhaust system and put a plug in the O2 bung.

So by not all, I have more than one vehicle I'm intentionally driving around with the O2 sensor unplugged? Would this number of vehicles be greater than two or less than four hundred?

FYI, I dyno tune cars for a living, been reverse engineering ECUs for a decade and running various shop's dynos for half that. When I make a broad statement like that it's a titdbit of technical information.

Actually, since the last few posts in this thread have been 50% me and I display quite a large amount of knowledge on the subject, you're either a troll or dumb.

#1 reason I don't post much to forums anymore. You don't help anyone by doing so. Anyone capable of understanding can usually figure 95% of it out by themselves, and they find you via email/etc to ask for a tip or to exchange info.

Look JOEY, some people read these forums for information. Some people may have read your original post about running a car with the O2 unplugged and thought it would be okay to do so.

I wasn't knocking on your knowledge as I don't know you. Nor do I know how many cars you have, nor was I being smartass or a troll as you put it.

Stop being a Dbag and realize that I was trying to help the "ecomodder" community by informing people its not good to run the car with the O2 installed in the exhaust, and not wired up properly.

#1 reason I don't like posting much to forums anymore is because of A-Holes like you bashing what people say, instead of thinking where people are coming from when they post things. You don't want Jonny-knows-very-little to read your post go home and unplug his $400 L1H1 O2 sensor, break it then come *****ing to you because he thought you said it was okay.