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2004 R1150RT Wideband O2 Sensors

At 4000 rpm, small throttle angles, the 1150 appears to be open loop. In the higher gears because you're going faster, the engine has to produce more power and your throttle is more open. At higher throttle angles the Motronic applies closed loop control.

I've spoken to the guys at PC and asked them about the chart below which shows where they believe the Motronic is closed and open loop. According to them, it is their understanding of it but they can't say for certain that it is accurate. The dark area is closed loop and the white area is open loop.

Why BMW has designated the various areas open and closed is harder to work out but it is either because closed loop is unreliable at those RPMs and throttle angles, or because they always want either leaner or richer operating conditions that closed loop would allow.

Back when I began this project it was partly because when shifting up in the low gears, I experienced slight roughness when the engine was warmed up, right at the "top" of the shift. It now appears that this is an area of leaner open loop operation. By reducing lambda with the Wideband we're also reducing lambda in these open loop areas.

pc1150map.jpg
 
As I mentioned earlier in the thread, I've been experimenting with some options for shifting lambda. A fully programmable, accurate solution, with the ability to datalog, is a Wideband O2 Sensor with a Wideband Controller like the Innovate Motorsports LC-1. (As a note, there are other manufacturers of this kind of product: Zeitronix, PLX, & wbO2. Also, I'm still working on a device that can pull a Narrowband O2 Sensor several percent to the rich side (this is looking pretty good).

The other day, I had someone build me a Wideband O2 Sensor (Bosch LSU 4.2), with a fixed-AFR shift Wideband Controller built into the cable (photo below, small controller not shown). At the moment it's not quite compatible with the Motronic MA 2.4 and it ends up running 9% richer than stock when it is set to 6% richer--still looking into it.

What was interesting was at 13.4:1-ish my bike's hot idle had increased to 1400 RPM from about 1200. I also noticed on a local trip to the Post Office I was in a higher gear (6th) than usual (5th). Like everyone, I shift by feel and was quite surprised that I was going 50 MPH at 2500 RPM.

While it's probably too rich (?), it seems the 1150RT likes its fuel.

RB

13point8.JPG
 
So back to the Narrowband O2 Shifter, here's a progress report.

Proto 2 of the Narrowband-shifter seems pretty well set for the R1150 series. I have found an interim connector supplier at a too-high-price but it does allow me to have some preproduction units built. (Proto 2 Photo below, it needs to be prettied up with black cable, etc. Also, there is no exposed chip on the production unit).

For installation: the procedure on an R1150 would be to pull the tank, connect the connectors in-line with the stock O2 sensor, run the grey cable along the right side of the frame, place the O2 circuit on the air filter cover, and attach a ground to the battery.

The specs look about like this:
(S1 means setting 1)

S1 14.7:1 (stock)
S6 14.35 +/-0.15 AFR (2% richer)
S7 14.15 +/-0.15 AFR (4%)
S8 13.8 +/-0.2 AFR (6%)

There are a lot of steps to get a product to production and to market but since this is a modification of a product already in production, Steve at nightrider.com will be working those issues. No dates yet on availability but it shouldn't be too long.

bmw.ied.2.JPG
 
Last edited:
wjg04oh said:
I had a chance to get out yesterday afternoon for a brief ride on the Interstate where I could get the bike into the upper gears. In 4th, 5th and 6th above 4000 rpm the AFR never got above 13.8, unlike the lower gears.

Does anyone have an idea why the Motronic apparently goes open loop (AFR 14.4) above 4000 rpm in the lower gears, but not in the upper gears? AFR stays right around 13.8 at steady speed on level going all of the time except above 4000 rpm in 1st, 2nd & 3rd!

I did observe a couple of times at higher rpm in the lower gears yesterday when the AFR dropped down to 13.8, but didn't get enough riding in to be able to replicate the conditions.

Last week I took some data from the LC-1 to see what was happening. The conditions of the plot below were:

Idled to log closed loop AFR.
Road in second gear between 4000-5000 rpm, throttle locked
Road in first gear 4000-5000 rpm, throttle locked.

Conclusions:
Above 4000 rpm in 1st or 2nd gear, the Motronic is Open Loop even if the throttle is locked-steady. Depending on throttle angle and load, the Motronic is leaner or richer than the lambda switch point, up to 4% lean.

On my bike 4% lean is 14.4; on a stock bike it would be 15.3:1, very lean. Add in some cylinder mismatch and the leanest cylinder could get close to 16:1?certainly in surging territory. This is the best measured evidence I've seen of surge-able conditions being created by the Motronic. This is much leaner than anything observed so far. As more bikes run LC-1s the Motronic will give up more secrets.

Also since the bike is Open Loop above 4K, the chart shows pretty good evidence of Adaptation being applied in the Open Loop area as the Open Loop AFRs seem well correlated to the lambda 0.94 target (13.8:1).

RB

fisrtsecondsurge.jpg
 
Any updates on the plug and play LC1 (almost) equivalent? I'm either going to buy an LC1 or your new plug and play device, but I'd rather buy something plug and play.

Any updates are appreciated!

Back a couple of pages ago I posted a short update, here. The Proto 2 photo is below, a product for all R1150s, R1100S and K-bikes as well--any BMW that is fueled by a Motronic MA 2.4.

The key pieces are the two BMW OEM connectors for which we now have a supply, you can see them in the photo. The connectors are what make it plug 'n play. Our manufacturing subcontractor has begun production on the first 25 units. Then after we've built the first couple dozen, we will gear production for a higher volume. Sometime in the next month I'll launch a web site that will allow the product to be delivered, the web site will be simple at first.

Because I also have the LC-1 installed that the same time I can compare Proto 2 to the gold-standard LC-1. For the past week, I've continued to ride Proto 2 which works very well. This weekend I'll be removing Proto 2 from my bike and sending it to a beta-rider.

I've also built an R1100, Motronic MA 2.2 proto which I'll post later this morning.

So progress is good, I'm evaluating thoroughly so that when we turn on production buyers will be able to expect prompt delivery.

bmw.ied.2.JPG
 
Although I'm posting this in the Oilhead forum, I am doing so because it further shows the benefits of installing something like an LC-1 on a another model of motorcycle. In this case it was a friend's 2007 F800S. We began discussing the project about a month ago and it is now complete. Most of the installation took place over about a week.

The F800S has a BMS-K the same as my friend Terry's installation last month on the R1200GSA. The same software settings worked but rather than a single load resistor to satisfy the BMS-K that an O2 sensor was installed, seven 1/4 watt 1000 ohm resistors were installed in parallel which you can see in the box below(he's a very neat craftsman) . His reasoning was that this would save space and slightly warm the box insides to keep it dry.

There are also two relays added inside the box. The first was a relay to switch the power, rather than use the O2 sensor Heater+. The second was a relay controlled by a panel switch to allow selection between the LC-1's two analog outputs. He has one setting at lambda 1.00 (14.7:1, stock) and a second setting at lambda 0.94 (13.8:1, 6% richer). This was a clever idea and he can switch mixture on the fly. (He comments on below.)

f800sbox.jpg


Hi Roger,

I managed to finish the installation work on the bike - only a faulty USB cable and a missing driver for the USB to Serial converter took some time to figure out.

And the first road tests (100 km today) have been really promising.

First, I'm happy and proud that everything worked in the first attempt.
--Function is easy to check with out lifting the seat to see the status led - what you do is to ride the bike at a steady speed, fix the throttle, read the current fuel consumption in the extended dashboard display, and flick the switch on. Two seconds later, the fuel consumption has stabilized it self at a slightly higher level.

--Your calceulations were spot on: 4,4 l/100 km became 4,7 l and 3,3 l/100 km became 3,5 l when the richer mode was switched on. I know the dashboard reading is not 100% accurate and there's only one digit after the comma, but both tests are indicating a 6% increase in fuel consumption - or something close to that on a spot measurement.

--So I'm not seeing a reduction in fuel consumption like you do, but it may be related to the non-ethanol fuel we got over here? (Editor's Note: I believe I get about the same fuel mileage overall at 6% richer due to being in one higher gear much of the time.)

The F800 was never surging badly at constant speed, but with the richer mixture, it's definitely running smoother and feels stronger in all closed loop conditions. Quite funny actually, because now you can really feel how hard the lean burning engine was [struggling] before.

I would like to take the bike to a Dyno at some point to have a performance run on both settings to compare them. My butt feeling says that the engine is a couple of horses stronger all the way from 3500 RPM to redline, and the torque dip around 4000 RPM seems to be gone. But a dyno run will tell if my butt is right?.

So it seems that your recommendation of the LC-1 complimenting my BoosterPlug installation very nicely?Open & Closed Loop. It's a real pleasure to ride the bike now with balanced richer fueling.

This setup is a keeper and is staying on my bike, and I'm happy that I have the capability to chose between fuel saving mode for cruising and power/fun mode for backroads and mountain riding.

I'm taking the bike to a rally tomorrow that will involve 70-80 km backroad riding, so I will get a good chance to test the LC-1 further.

Please accept my compliments for a bright idea and thanks for sharing it with me.

All the best.
 
R1100 Prototype Lambda plug n play device.

Today I got out for a test ride with an R1100 prototype device. It's appearance is just like the R1150 verson except the connectors are different so I built up it up with salvaged R1100 connectors on either end. Then I took a used R1100 (thimble style) O2 sensor, lambda element grounded to the case, different from the R1150 style, and installed the R1100 O2 sensor in my R1150RT's second O2 bung.

Lastly I built an adapter cable to convert the R1100 style output connector to the R1150 connector. So the build-up was:

R1100 O2 sensor, connecting to:
R1100 Proto lambda device with R1100 connectors on either end, connecting to:
R1100 to R1150 connector cable so that I could plug it into my R1150

It worked as well as the R1150 version, maybe a little better. I believe that is due to the R1100 O2 sensor having a more powerful heater (guess?). There was no discernable temperature effect, meaning it was less sensitive to exhaust temperature than the R1150 sensor.

It works well enough now that I will send it to a few R1100 owners soon for their feedback.

The R1100 OEM connectors are decades old. It may be that the package will be a lambda shift device and a new R1100 O2 sensor, as a way of getting the needed OEM connector. It will add to the cost but many R1100 O2 sensors are very old and would probably benefit from replacement.
 
Here another LC-1 install on a GS. The idle AFR variation he refers to was due to misadjust throttle stops. The throttle stop issue might not have been apparent for a while and it preceded the LC-1 install. One of the nice benefits here is that the constant AFR monitoring is a terrific diagnostic tool.


I've been following your threads extensively regarding the wideband 02 sensor installation on your R1150RT. All the data and discussion you posted in the forum really got me interested so I went ahead and got the LC-1 kit for my '02 R1150GS.

Installed it on Sunday, everything worked as planned. I put the 14.2 AFR tune you had posted on the installation guide in, adjusted the TB's for idle and balance again (idle was at like 1500 after the bike warmed up as it should). Today I took it out for an extended ride, about 250 miles.

WHAT A DIFFERENCE.

Acceleration across the board is better. Even starting out in first gear, the bike doesn't feel like it wants to stall below 1700 RPM. I can easily use one higher gear in all my driving, and there's no more pinging if I crack the throttle at low RPM.

Cruising at 75 mph was so much more enjoyable as well. The buzzing in the hand grips was drastically reduced, and the throttle seems a lot more forgiving. Before the mod, the throttle was so sensitive it was like a balancing act between accelerating and decelerating, very hard to maintain a set speed (a lot of people call this surging, maybe, or lack of throttle finesse. It's hard to keep steady even with everything setup perfect ). After the mod, I feel that the throttle is more forgiving, much easier to control. Much more like my old R65 used to handle.

I just wanted to say thanks for all your hard work and dedication to this project! It made the install a breeze.
 
Great news for my 1998 R1100R!

Great news that this may be "THE" solution for the R1100R I just bought. Surged terribly when cold, better when warm and little when hot. Due to feedback from this forum I ran techron, cleaned the tank of old gas, replaced the fuel filter and checked the hoses, added Q disconnects, cleaned the BBS's, added premium gas, grounded the neg. side of the injectors, chirped them with 12 volts to assure opening, and changed out the oil temp sensor (thanks to rxcrider!!) for a known good one. If anything the bike runs worse! much worse! It's a my indie ex-BMW master tech for help. I'm in his hands now. I am flabbergasted that everything I have done has not helped and most got me into more problems. I was going to buy a Harmonizer but have gotten tech-phobia! I will be watching for this to be available as you know more about this system than anyone I can imagine!
Thanks and keep at it.
Ralph

R1100 Prototype Lambda plug n play device.

Today I got out for a test ride with an R1100 prototype device. It's appearance is just like the R1150 verson except the connectors are different so I built up it up with salvaged R1100 connectors on either end. Then I took a used R1100 (thimble style) O2 sensor, lambda element grounded to the case, different from the R1150 style, and installed the R1100 O2 sensor in my R1150RT's second O2 bung.

Lastly I built an adapter cable to convert the R1100 style output connector to the R1150 connector. So the build-up was:

R1100 O2 sensor, connecting to:
R1100 Proto lambda device with R1100 connectors on either end, connecting to:
R1100 to R1150 connector cable so that I could plug it into my R1150

It worked as well as the R1150 version, maybe a little better. I believe that is due to the R1100 O2 sensor having a more powerful heater (guess?). There was no discernable temperature effect, meaning it was less sensitive to exhaust temperature than the R1150 sensor.

It works well enough now that I will send it to a few R1100 owners soon for their feedback.

The R1100 OEM connectors are decades old. It may be that the package will be a lambda shift device and a new R1100 O2 sensor, as a way of getting the needed OEM connector. It will add to the cost but many R1100 O2 sensors are very old and would probably benefit from replacement.
 
Great news that this may be "THE" solution for the R1100R I just bought. Surged terribly when cold, better when warm and little when hot. Due to feedback from this forum I ran techron, cleaned the tank of old gas, replaced the fuel filter and checked the hoses, added Q disconnects, cleaned the BBS's, added premium gas, grounded the neg. side of the injectors, chirped them with 12 volts to assure opening, and changed out the oil temp sensor (thanks to rxcrider!!) for a known good one. If anything the bike runs worse! much worse! It's a my indie ex-BMW master tech for help. I'm in his hands now. I am flabbergasted that everything I have done has not helped and most got me into more problems. I was going to buy a Harmonizer but have gotten tech-phobia! I will be watching for this to be available as you know more about this system than anyone I can imagine!
Thanks and keep at it.
Ralph

Ralph,
Rather than guessing about how this will work on a bad surging R1100, the beta unit is in Oregon now being ridden on an R1100RT for the rest of the month by one of the bmwmoa members who's a regular in this forum. I'd like to send the beta unit to you when he's done, when you're back in NH if you would be willing.
RB
 
That would be great.

Roger,
I'll know how good we can get this R1100R later in the week. I am in NH now and would love to try the Beta when it's back. I don't have any add-ons to improve this bike yet as I have only owned it long enough to ride it about 450 miles (bought just before snow here. I have no way to know but only 6,000 miles in 14 summers may be due to this issue. I will try to contact the origional owner to find out if it surged from the beginning or if I am seeing a new issue. Feel free to PM me if that works for you.
Ralph
 
Roger - do you know how soon the bike starts using the O2 sensor to trim the fuel? Specifically, if Ralph had a broken heater wire, could that cause his cold running issues?
 
On the R1100s, the heater comes on with the fuel pump, so it essentially runs all the time. Closed Loop control on the 1150 starts at about 3-4 bars on the RID. On my 1150 it seems to take about 4-6 mins.

I don't have a cold start profile on the 1100 yet but do have one on the 1150 single spark, dual spark and 1200 GS. They all have either a few or several minutes. I'd bet the curve is similar for the 1100. If you look at the top chart below, the first 4 minutes of the top curve shows the warm up enrichment function with much richer mixture. (The bottom curve also show the enrichment and there's a discussion of this plot a few pages back.

It's hard to guess what's happening on Ralph's bike. If he installed a Wideband O2 datalogger, most likely he'd know right away what was happening to the bike when cold.

Is there anything affecting: air balance when cold, throttle cable evenness of L/R throttle actuation, cold start lever somehow unbalancing the throttles, fuel injector cold performance, etc.

There isn't a lot of information you can read from the MA 2.2 but you can readout error codes. That might be worth doing.



lc1vsbmwied.jpg
 
We've been running some tests with the LC-1 and my GS-911 on Wally's bike. I've learned about several differences on the R1150GS single-spark Motronic. The important differences are that the ECU's microprocessor seems slower, it's data acquisition seems less frequent, and the GS locates its O2 sensor in a place that seems to have less air flow. As a result, at regular idle, the Closed Loop period is a VERY slow 4 to 5 seconds. One to two seconds would be the norm.

Other than that, the LC-1 and single-spark Motronic MA 2.4 play very well together. Here is a beautifully adapted cold start sequence with some notations.

RB

wallycoldstart.jpg
 
Thought I'd provide some updates on what's been going on lately.

There are three beta devices circling their way around the US and Canada?r1100, R1150s. All are progressing very well.

I took delivery of an R1200 wiring harness and harvested 4 female O2 connectors so I can build beta units for R1200s and F800s soon.

For the Narrowband device I expect to get production approval units this week.

On My R1150RT with LC-1
I added a small switch to my lc-1 connector box. The switch has three positions: off (so I can run open loop when I want), connect to LC-1 analog 1, and connect to LC-1 analog 2 (analog 2 is usually for the gauge but can be programmed like analog 1). The switch connects to the black (O2+) wire in the O2 connector cable. This allows me to do an a/b comparison of two different mixtures with just a switch.

I rode at lambda=1 which is 14.7:1, I'm doing it for comparison testing. I'll also try a very lean setting soon like 16.2:1 to measure economy.

Here is an LC-1 report from a recent self-done implementation.

"I'm really amazed by the performance of the motor with the LC-1. Peoples who don't try it are lacking something. I loved the old BMW powered with carburated motors because they had torque. Now with the LC-1 I have this feeling. Today I went for a high speed ride and I would be surprised to look at the time required to do 1/4 of miles. The motor revs fastly with authority. I'm in love with my bike.

My AFR is settled at 0.925 and 0.915.

The only drawback is idling which seems overly rich when it is cold and with the fast idle. The motor doesn't like to be kept at idle when cold because after some time it doesn't idle smoothly until I open the throttle to rev the bike. As stated I suspect overly rich mixture when cold and the exhaust gas stinks.

Thanks a lot for everything."
 
I wanted to update the thread with a status report. The narrowband-shifting device manufacturer continues to make progress. Below is a photo of the device, with a generic connector to which a model-specific (R1100, R1150, R1200, F800) cable harness with OEM connectors gets attached. The installation procedure will be: plug in the OEM connectors (and connect a ground wire in some cases).

Inside the "black box" is a small data acquistion and digital processor that intercepts the stock signal and sends a modified version to the Motronic.

There should be a production version with a small first run in about a month. This probably seems like a slow process but the manufacturer is handling this in a professional manner, which takes time.

narrowshiftproto.jpg
 
Narrow Band O2 Sensor Shift Device Beta Test Report

June 2, 2013, prepared by Happy Wanderer

I?ve returned from a 4,000+ mile beta test of Roger04RT?s narrowband O2 sensor shifting device on my 2000 R1100RT. Roger put one together for the 1100RT that was plug and play for beta testing purposes. Installation involved removing the right side fairing panel, unplugging the O2 sensor connector and plugging his device in series with existing connectors. Unlike the 1150 there is no ground wire required and installing it couldn?t be simpler. The device itself was placed under my seat on top of the air box for easy access. A 2mm hex tool, a few cable ties, resetting the ECU and about an hour is all that is required. The unit was installed on a well tuned stock bike known to be surging and averaging ~41 miles per US gallon.
I did some initial local testing initially at both recommended test settings which were:
F6 = 14.15 / 1 AFR or 4% enrichment
F7 = 13.8 / 1 AFR or 6% enrichment
Both settings produce noticeable changes and improvements. Initially I found F7 produced better results but long distance testing proved that F6 gave a better balance of performance and mileage improvements once adaptation by the ECU was allowed to complete.

Riding Observations:
- The first thing I noticed was in low gears (1, 2, and 3). Steady throttle in these gears typically produce a lot of annoying ?hunting? or surging which results in a jerky ride. This was smoothed out significantly with the device.
- Roll on throttle performance is greatly improved especially in the higher gears. The wonderful thing about this is that you can put through those small towns in 4th or even 5th gear without the usual complaints from a big twin engine. Goodbye jerky, surging ride through small towns.
- Available torque at low speeds in the higher gears is also much better. This allows you to slow down without shifting gears and then pull away again in a smooth controlled fashion. I normally downshift at around 3,000 RPM but found myself and bike quite comfortable down at 2,000 and even lower in some cases. When I noticed this I was quite surprised so I went riding around some back streets where traffic was light to nonexistent and tried it again several times. There is definitely a lot more smooth acceleration power available at low RPM. No pinging, no complaint from the engine at all, it just rolls on and away you go.
- The transition from on and off throttle is also smoother. This is great when adjusting your speed in traffic. The throttle is less snatchy.
- The fuel cutoff lurch you feel on an 1100 around 1500 to 1700 RPM as you come to a stop in gear is less pronounced. Still there but not as harsh.
Mileage Data:
My former average was 41 mpg. The data I collected over 4,000+ miles of riding shows it is now 44.6 mpg or 2.4% better on average.
Noteworthy points in the data: (see table below)
- Change in performance from the 7 setting to the leaner 6 setting
- Mileage improving over time during the first several days (Motronic 2.2 ECU adapting)
- Performance at high altitude desert conditions (Utah and Arizona) is just excellent.

To summarize the riding test I would say my bike is much happier running a slightly richer mixture. And happy bike = happy wanderer. J Although the surging is not completely gone as has been experienced and documented on the 1150 it is reduced to a much more manageable level. I am highly suspicious that this is due to my fuel injectors not being perfectly matched but having them cleaned again and re tested will have to wait until much later in the riding season or perhaps when I am gone on one of the other bikes for a couple of weeks!
Oh and one more important comment. I have to remove the beta and send it back to Roger now?
And I am NOT happy about that one bit!
 

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Part 1 of 4

Earlier in this thread, Terry posted on the installation of dual LC-1s on his 2011 R1200GSA. Since that time he's ridden thousands of miles but importantly, has continued to log air-to-fuel ratio (AFR) and engine data by using the LC-1s and a GS-911 in tandem. I've digested several of his test rides into four charts that I'll explain in four posts. The BMSK has some very good features that solve problems of the Motronic MA 2.2 and 2.4.

R1100s and R1150s use two generations (or three if you include dual-spark) of Motronics for controlling spark timing and fueling. Each of those systems works with one O2 sensor that is placed in a spot where it measures the average oxygen content of the exhaust. The R1200 has two O2 sensors (and knock sensing) which supply additional data to its engine control unit called the BMSK.

On an R1200, the BMSK manages two mostly independent Closed Loop programs. This means that it can nearly perfectly balance the left and right cylinders. This is an important feature that essentially eliminates surging. On 1100/1150s we meticulously balance air with TB syncs and valve adjustments but have to ignore fuel imbalances. Not so on the 1200, using its two O2 sensors it can easily equalize fuel, keeping left/right power (air plus fuel) equal?no surging, and a smoother engine. On 1100/1150s your choices are to clean and measure your injectors for balance or to add a few percent more fuel so that all the oxygen gets burned, making fuel imbalances less important, diminishing surging and making the engine smoother.

Although this is an Oilhead forum I feel that some of the insights from the R1200 will be beneficial to R1150 and R1100 riders too. So to that end Terry disconnected one of this two O2 sensors, reset his BMSK so we could see what things look like before Adaptation cleans-up the left/right cylinder differences and then reconnected the O2 and watched what happened (next post). He also made a short test ride with an O2 sensor disconnected to see what happened when an O2 failed.

One O2 Disconnected, BMSK Reset, Cold Start
Using the LC-1s, Terry's AFR has been programmed 7% rich and therefore his AFR runs around 13.6:1. In the left-hand LC-1 chart below take a look at the connected cylinder's AFR (purple line). One of the first things you can see is that the R1200 gets into Closed Loop operation very fast, only needing about 20 seconds or so (my 2004 RT takes a few minutes to warm enough to run Closed Loop). If you look very closely at the chart there is a difference between the purple and black lines at startup--about 4% AFR difference. Terry's bike is well tuned (TB Balanced and Valves) so I believe is the natural AFR imbalance of his motorcycle, a combination of a small fuel and a small air imbalance. This natural imbalance is interesting because it could easily exist on any 1100/1150, we just wouldn't know it.

The cylinder without an O2 is running pretty rich, in part because he has an air-temperature shift device adding 6% and in part because there is a slowly declining warmup enrichment (notice the injection time coming down), but also because without an O2 on one cylinder the BMSK seems to be leaving a margin of error toward the rich.

Looking on the right hand chart, which is GS-911 data over the same time period as the LC-1 chart on the left, you can see the base injection time (blue line). When cold the pulses are about 4.5 mS long and within 20-30 seconds they have been reduced to 2.5 mS. The same base time is used for both cylinders but there are also two LCFs (Lambda Correction Factors), one for each cylinder. Looking at the red line you can see that the Closed Loop program which creates the LCFs reduces the fueling to about 82% of the base time. The disconnect cylinder doesn't have any way to calculate an LCF and it stays at 100% and that cylinder remains rich.

The key takeaways here are: fast warm-up with O2 connected, 4% difference between the cylinders with no Closed Loop correction and the LCFs which are the short term Adaptation Values that I've mentioned before in this thread. Later there will be some charts showing long term Adaptation. You can also see what's going to happen in the short term if you lose an O2 sensor.

bmsko21.jpg
 
Part 2 of 4

In Part 1 we saw the 4% initial imbalance between the left and right cylinders of Terry's 2011 R1200GSA and then what happened in Open Loop with only one of the O2 sensors attached. The LCFs (lambda control factors) also showed how the BMS-K calculates its Adaptation Values. Next is how the injection time and both LCFs interact when the second O2 sensor is reconnected.

Reconnected #2 oxygen sensor
Looking at the lefthand side of the first chart below, at about 9:02 (point labeled 1) the second oxygen sensor is reconnected. It only takes about 15 seconds for the BMSK to smoothly compute the second cylinder LCF and lock Closed Loop, and in the process make a 14% fueling correction. If you look closely at the LCFs on the righthand side, they are 8% apart, more than immediately after being reset (about 4% at the start of the chart in post 1 on this topic). I don't have an explanation for this difference.

At point 2, the throttle is blipped, the BMSK sets both LCFs to 1.00 (it's in Open Loop mode) and you can see that the AFRs both go rich, but one is richer and the richness lasts longer. Later, when the BMSK has fully adapted, I'll show that both cylinders are nearly perfectly AFR equalized. The BMSK is simply amazing.

bmsko22.jpg



Looking at the chart below, the lefthand LCF graph is the same as above, but the righthand graph shows what's happening with the idle stepper motors (which seem to run in sync in the data I have on hand). What the BMSK does next, knowing that it has both O2s running, is to begin normalizing other aspects of its operation. First notice in the LCF graph on the left that both LCFs head together several percent richer. Since almost everything else has stayed the same (spark timing, RPM and TPS), why is the BMSK Closed Loop routine requiring more fuel (as seen in the LCF trend upward)?

The simple answer is that just before connecting the second O2 sensor, the average of the two LCFs was 0.92 (1.00 vs 0.84). After the second O2 is plugged and its LCF has adjusted, the average LCF (on the right of the chart) is 0.86, less fuel on average to hold the idle at around 1150.

The other interesting thing going on is that the idle stepper motor value is dropping. It looks like when both cylinders are balanced by the Closed Loop programs, both O2 sensors running, it takes less fuel (average LCF lower) and less air (idle motors lower).

So there's the Cold Start sequence and the role of O2 sensors, idle stepper motors and the BMSK's symphonic handling of its sensors and the LCFs (Adaptations). I believe that this is relevant to Motronic MA 2.2 and 2.4s (1100s/1150s) because there are things like this going on inside those ECUs as well. I hope this helps to illustrate the types of processes in Closed Loop that are more visible on the BMSK.

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Part 3 of 4

Test Ride on One O2 Sensor
On one of the tests, Terry left the cylinder 2 O2 sensor disconnect and went out for a ride to see what would happen. He told me that he barely made it out of the driveway the bike was running so roughly. And that's no surprise, one of his cylinders was in Closed Loop and running an AFR of 13.65:1 and the other was Open Loop and running and AFR of 11.4:1, hugely richer.

He persevered though and got out for about 10 minutes of mismatched torture before he reconnected cylinder two's O2 sensor.

The chart below shows about 6 minutes of that ride. It is remarkable. If you look closely, you can see that cylinder two's Open Loop fueling starts to converge towards Cylinder one's Closed Loop fueling. How is that happening? I can't be 100% certain without more tests but it seems pretty clear that the BMSK is using data from cylinder one's Closed Loop to estimate the fueling needed by cylinder 2. Wow!

A more important thing to note is the enormous variation in fueling when there is no O2 sensor. Cylinder one's fueling is tight to 13.65:1 whereas cylinder two's fueling varies grossly between 11.4 and 13.65. I saw this exact behavior on the R1150's Motronic and expect it would be the same on R1100s (except when an Open Loop coding plug was used). This certainly appears to be BMW/Bosch's Limp Home fueling strategy--significantly vary the mixture and hope that the catalytic converter gathers some oxygen during the lean peaks so it can function at times.

Running one cylinder with O2 and one without turned out to be a great way to show what happens when you run BMW motorcycles in Open Loop. There is a huge takeaway here: If you disconnect the O2 sensors and add a Power Commander V, you will run on the Limp Home fueling pattern and lose all the features that I've shown in these first three posts.

On the 1100s and 1150s, Power Commander has a Wideband O2 sensor so the behavior is different but as I will explain in a few days, not really optimal. (LGW loaned my a PC III USB with Wideband and I've made some tests against the LC-1.)

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