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Introduction and O2 Question


roger 04 rt

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I got out today with the GS-911 attached and a PC in the Top Case for a 100 mph run up a section of posted 50 mph highway that runs through a flat swamp nearby. I didn't get past fifth gear before running out of highway. I continue to operate at 52 psi fuel pressure and a mixture of 13.8:1 no BoosterPlug or any other modification to my '04 RT.

 

The idea was to see when and where the Motronic runs the Closed Loop program. I've got some charts coming but here are a few observations. Keep in mind that the max 95HP is at 7250 RPM.

 

--Closed Loop was operational at 100 mph (The engine seemed very smooth here)

 

--Closed Loop was operational in 2nd, 3rd, 4th gears at nearly 6500 RPM.

 

--Closed Loop was operational at 48 degrees throttle (80 degrees is wide open) going 100 mph

 

--In 3rd gear, while accelerating to 70 mph the Motronic was Closed Loop a lot of the time. Same in 4th gear to 90 mph.

 

--In 5th gear, WOT Motronic stayed mostly Open Loop from 65 mph to 100 mph. But as soon as I "relaxed" the throttle to about 3/4 open at 6400 RPM, Closed Loop kicked in. Amazing!

 

Given the amount of time and operating areas where the Motronic will enforce lean Closed Loop, I think it gets easier to see the advantages of mixture richening by using a Wideband O2 to shift Lambda from 1 to something less--0.94 in my case.

 

--At 6000 RPM & WOT the injector was on for 7.2 milliseconds. One revolution of the engine only takes 10 milliseconds at that RPM. At 7250 RPM (max horsepower) each revolution is only 8.3 mS. The injectors would be open 90% of the time!

 

(The air temperature was 90F today; had it been 20F the 7.2 mS injector pulse would lengthen to 8.1 mS. Were I to boost my fuel output using a -20C air-temp shifter on a 20F day, that pulse would lengthen to almost 8.6 mS. More than 100% on-time! Fuel pressure is a better method for boosting injector output (compared to IAT shifting or PCs or Techs) since it doesn't require the injector pulse to be lengthened.)

 

That's the raw data. I'll try and post a chart tomorrow after I've thought about it further.

RB

Edited by roger 04 rt
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I thought some might like to see the chart but I don't have time to provide the detailed annotation yet. Briefly, the Green line has two states: Closed Loop program running is the HIGH state but forget the label on the right side of the graph, it's just used to shift the 1/0 to the top of the chart. The red and blue curves use the left axis labels.

 

There are 6 RPM peaks. They are gears: 1st/2nd, 2nd, 3rd/4th/5th. I'll not them on the photo later when I get time for further detail but for now the comments in the prior post apply to this chart.

 

In first gear, Closed Loop seems to stop at 4000 RPM. In Neutral (not on the chart) Closed Loop ends around 3000 RPM, or maybe lower.

 

As I mentioned in the prior post, not that in 5th gear, 6350 RPM and 45+ degrees of throttle, the Motronic goes Close Loop!

 

closedlooprange1.jpg

Edited by Kathy R
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  • 2 weeks later...

How the Motronic handles spark advance has been something of interest. When the data in the last post was collected, I also collected ignition timing data, plotted below, for reference and for those who are interested. This data is for the Motronic MA 2.4, Pink Coding Plug.

 

Unlike fueling which can be modified externally, spark advance is under the control of the Motronic's internal program so can't be modified without an ECU chip replacement.

 

The charts below show spark advance compared to RPM and to throttle angle. In the RPM chart you can see that advance is increased with RPM, reaching a maximum of about 43 degrees above 4000 RPM.

 

In the TPS chart though you can see that the maximum advance is only for throttle angles below 18 degrees (80 degrees is WOT), and is then reduced for wider throttle angles. From 50 degrees to wide open throttle the advance is limited to 20 degrees.

 

The other thing worth noting is that while the spark is advanced with RPM up to certain throttle angles, there are a lot of points scattered well off the curve. This shows that there are other factors that the Motronic uses in its timing calculations.

 

sparkadvancescatter.jpg

Edited by roger 04 rt
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Interesting plot.

 

I believe the plots would be quite orderly if your software took the first chart and plotted separate lines for a few TPS angle on it. Can also be experimentally by doing runs at a fixed TPS angle as the engine speeds up.

 

I've been wondering for a long time if the AIT influences spark timing? Never got a good answer. Not that the other sensors might not also have an influence in a perfect world.

 

The BBP chip has a choice of step-up mod levels with, I assume, hotter and hotter spark advance.

 

Ben

 

 

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Is it just me or does anyone else see the possibility of getting more power at using 5/8 throttle if RPMs are low? There is 10 degrees more advance there.

Edited by roger 04 rt
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A scatterplot doesn't show it, but those curves (as I described) should be quite orderly (but not monotonic). If BMW left 10 degrees sitting around, I assume they felt they had good reason to fuss (like detonation).

 

After doing carb switcheroos on two BMW models (with good results), I believe it is very hard to modify fueling and spark without the resources a manufacturer has available. So an LC-1 maybe be a fun research tool, I doubt a Power Commander is likely to beat BMW's tuning.

 

Ben

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Hello Ben,

Say what you will but I for one am completely convinced these oilheads will perform far better with a richer air fuel ratio than what they come with from the factory. The factory guys are trying to reduce emissions and in so doing tradeoffs are made with performance. The LC-1 is a favorite tool of the automotive tuner because it just works and is hardly a toy. In my case I chose not to use an LC-1 to obtain a richer mixture mainly because I don't own a PC and the LC-1 software just won't run on a Mac and I am one of those stubborn Mac users that would rather return to an all analog world than own a PC. All this said, I think the LC-1 is probably the best way to richen the mixture because it allows the Motronic to do its thing as it normally would in closed and open loop. Best way to go, imo. Oh, and the data gathering capability of the LC-1 is super and takes much of the guess work and seat of the pants feel out of the equation.

Edited by JamesW
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Hi JamesW,

Yup, I think it's earlier in this thread but here is one of the most well known curves is internal combustion engine tuning. An aircraft readily and simply shows this effect. Climb to cruising altitude, lean your mixture to stoichiometric (or peak EGT), record speed. Richen mixture to Best Powe, fly faster (due to increased HP), and run with cooler exhaust temperature. The LC-1 is a mixture controller, directly using BMWs well designed fueling tables.

 

Further, it turns out that every engine has a leanness it doesn't really seem to like. For our Oilheads that often seems to be stoic. Run richer, run smoother.

 

powerout.gif

Edited by roger 04 rt
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Just a couple more points for those interested. The LC-1 let's you slide the vertical line labeled Stoic to the left or to the right--richer or leaner. What it does together with the Motronic is really that simple.

 

Slide the Stoic line right (which I experimented with and showed earlier in the thread) and the Boxer engine starts to stumble.

 

Slide the Stoic line left and the engine is smoother and stronger, especially cruising at speeds between 35 and 100 mph (closed loop range). It only takes a few percent. In addition you end up cruising in a higher gear a lot of the time because of the additional power and smoothness. Although I've shown a lot of data in this thread, this mod is not rocket science, the boxer runs better with a bit more closed loop/cruise fuel.

 

One thing you don't get though is more horsepower at WOT. In that condition BMW has already set the mixture to Best Power. You might if you advanced timing but I leave that to others who are interested.

Edited by roger 04 rt
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Here is the final mounting of the Aeromotive 13301 adjustable fuel pressure regulator that I used to richen Open Loop fueling 10% (20% increase in pressure to 53.5 psi).

 

It is mounted to the frame using an included mounting bracket, on the right hand frame near the alternator. (I misread the torque value and broke the bolt which led to having to drill it and back it out.)

 

The mounting bracket is soft steel and was easy to twist with a vise and adjustable wrench. You can see the fuel line routing in the photo below. After taking the photo I realized that I could attach the battery vent hose (no longer needed with the Odyssey battery) to the regulator atmospheric vent.

 

fprfinal.JPG

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Hi JamesW,

Yup, I think it's earlier in this thread but here is one of the most well known curves is internal combustion engine tuning. An aircraft readily and simply shows this effect. Climb to cruising altitude, lean your mixture to stoichiometric (or peak EGT), record speed. Richen mixture to Best Powe, fly faster (due to increased HP), and run with cooler exhaust temperature. The LC-1 is a mixture controller, directly using BMWs well designed fueling tables.

 

Further, it turns out that every engine has a leanness it doesn't really seem to like. For our Oilheads that often seems to be stoic. Run richer, run smoother.

 

powerout.gif

 

I wish people would stop talking about stoich as some kind of important benchmark. First of all, there are various criteria of performance and each has its own different best A/F and even that criterion and that A/F changes with RPM.

 

Whatever chemical ideal in the lab is stoich, it is different in engines and different in each engine.

 

The BMW boxers have never been great breathers and so stoic A/F has never been of much significance.

 

Narrow band O2 sensors have traditionally come in only one form and that is stoic rated. If you know feedback theory, you know a sharp sensor of the sort used on the Oilheads funnels you in a narrow direction which is not easily manipulated by electronics smarts.

 

Ben

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In the spirit of a picture is worth a thousand words, I've added a block diagram of the Motronic MA 2.4. This is my interpretation from research, the data I've taken throughout this thread and some deduction. I believe it to be a good-fit, functional representation of how the Motronic does it's job as a fueling and spark computer. As I find errors, I'll correct the diagram. (i.e. I don't know if there is a cold oil temperature spark timing adjustment.)

 

Next I plan to post other diagrams showing how the Wideband O2 mods of this thread affect the system, as well as diagrams of how the PowerCommander and Techlusion interact with the Motronic MA 2.4. Eventually I'll add all four diagrams with a PDF link.

 

motronicstk.jpg

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Before going to the diagrams of the Wideband modication, here is a view of the differences between the Open Loop and Closed Loop fueling.

 

Open Loop fueling starts with the TPS and HES signals and proceeds through adjustments for air temperature, barometric pressure, etc., proceeding to a fuel pulse being injected into the engine (ignoring the Adapt box for a minute).

 

Closed Loop fueling is a software program that begins with an Open Loop fuel pulse but then quickly uses measured Oxygen from the exhaust (the O2 sensor) to determine whether the mixture is richer or leaner than the target set by the O2 Sensor (switch). With a bit of trial and error, it locks into a range of fuel pulses that alternate between being a bit rich and a bit lean. The Closed Loop program is an aggressive "enforcer" of the mixture specifed by the O2 sensor. In a stock system that mixture is a lean 14.7:1 (for gasoline).

 

The Closed Loop program also has another activity which is to compare (the Compare box) the Closed Loop result with the Open Loop calculation. Over time, if these fuel pulses are different, the Closed Loop program "teaches" the Open Loop program some adjustments (the Adapt box). This means the Open Loop program gets corrections that can take into account: fuel type (e.g. E10 or gasoline), fuel pressure, air filter restrictions, fuel injector contamination, and throttle body, valve & cylinder accumulations. A weakness of the 1150 Motronic is that it treats both cylinders equally, which means we have to manually balance (left and right cylinders) the air (TB and valves) and fuel (injector cleaning and matching).

 

The diagram below can give an idea of which engine modifications will have a long-term effect on engine performance and which will be "learned out" by the Motronic's Closed Loop program.

 

My objective with the Wideband O2 project was to leave the many functions of the Motronic intact even while richening the overall mixture.

 

motronicloops.jpg

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Before posting the next few diagrams, I spotted a function that I'd left off the Motronic that is relevant to any fueling modifications that disable the Motronic's Closed Loop operation (1150 Motronic MA 2.4). If you look back at the previous two charts, they've been amended to add a "Limp" function to the final fueling decisions.

 

The Limp box is now the final step in Open Loop fueling, just after Adapt values have been applied. The Limp function as I have measured it (plot below but no BMW documentation that I can find) expands the variation of Open Loop fueling to a 10% range. That is twice the amount of mixture variation that occurs in Closed Loop. The full post was here, Open Loop fueling variation. Although there is speculation that Limp Home is a rich mixture, the measurements say that it is 5% richer than normal and 5% leaner than normal.

 

What that means on an 1150 is that if you disconnect the O2 sensor and run a Powercommander, Techlusion, 3.5 Bar pressure regulator or BoosterPlug as an Open Loop fueling enhancement you can count on the Motronic to vary the fueling in a 10% range, like the plot below.

 

The next post will be a block diagram of the Wideband O2 system.

 

open52psireset.jpg

Edited by roger 04 rt
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OK, but in the real world if you run open loop with a 3.5 BAR fuel pressure regulator with a Booster Plug and get from 43 to 49 mpg with absolutely no surging or backfiring just nothing but smooth stable performance what, in practical terms, is gained from allowing closed loop operation? Of course you eliminate the ability of the Motronic to learn from open loop operation and pass on to closed loop but what's the harm? Especially if you get great performance.

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Most of what I've written about is from measuring the 1150 motor and Motronic, so I'd say that's real world.

 

You've gotten a good result and when I rode Open Loop I thought the result was good too. Going further, many Techlustion and Powercommander implementations leave the Motronic in Open Loop. That said, there is a difference and I wanted to document what that was.

 

With a programmable Closed Loop implementation, you can set a mixture (e.g. 13.5 or 13.8 or 14.1) and know what it will be. With an Open Loop solution, you estimate how much fuel you'll be adding and how the result turns out. Using an Open Loop implementation, the Motronic will assume that it has to take measures to deal with a non-functioning O2 sensor and move the mixture in a 10% range around your target. For the same feel, I believe that will take more fuel.

 

My point is not that it is a bad thing to do, only to describe the differences of operation.

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Here is the block diagram showing how I've installed the Innovate Motorsports LC-1. The stock Narrowband O2 sensor has been removed, and it its place the LC-1 is installed. With months of measurements under my belt, I'm now confident that the Motronic functions the same with this sensor as it does with the stock sensor, it just programs and enforces a richer mixture.

 

Looking at the diagram you can also see that I've boosted the fuel pressure. This is an optional enhancement. When you shift the )2 setting from Lambda = 1 (stock) to Lambda = 0.94 as I've done, if you do nothing else the ADAPT box in the diagram will learn over time how much it needs to adjust the fueling to get the L=0.94 result. It takes time to adapt but eventually it does. Every pulse it sends out becomes several percent longer.

 

The other option is to give the Motronic a headstart. One way is to add something like a BoosterPlug. It tells the Motronic the air is 20C colder and that results in a 6% richer mixture. The Motronic then has less adapting to do and gets to the final result faster.

 

The option I choose was to boost the fuel pressure by an amount that was equal to the shift in Lambda (plus an amount for E10 fuel) so that the Motronic would have almost no Adaptation work. (Fuel Pressure balances Lambda shift.) That means two practical things: as soon as you fire up the Motronic it's in the right ballpark; and every cell of the fueling table has been corrected (every pulse is affected by the increased fuel pressure), versus the coarser correction of the Adaptation process.

 

It seems like I've made a lot of measurements and tests to arrive at a simple solution for mixture enrichening but a side benefit is that a lot was learned about how the Motronic does its job and I've got a good confidence that the LC-1 implementation is compatible and that the Motronic is fully functional and operating as intended by the designers, just richer.

 

Tomorrow I'll add a block diagram for a Powercommander and Techlusion implementation.

motroniclc1.jpg

Edited by roger 04 rt
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Hi Roger, e-mailed the LC-1 folks to see if they can pre-program an LC-1 to 13.5:1 AF ratio as this might be a good option for us non-PC users.

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Another way to add fueling to an 1150 (or 1100) is by using a PowerCommander III, block diagram below. This product includes a Wideband O2 sensor and an Add-On Fuel Table computer. It is a standard product, that can easily be added to an 1100 or 1150. Many believe that it is necessary to "Dyno Tune" the Powercommander after installation, but you could richen the mixture without having to go to that expense.

 

One reasonable way to use the PC III would be to install it along with its Wideband O2 sensor, use the included software to program the O2 sensor Lambda to 13.8, and fill in the fuel table with 6% everywhere, perhaps tapering off toward the high RPMs and high TPS angles. In this mode it would be similar to the LC-1 and somewhat easier to install.

 

With the O2 sensor programmed to 13.8, the Powercommander claims to operate its own proprietary Closed Loop program (see the shaded Closed Loop area in the second chart). That said, major parts of the Motronic are disabled when the PC III is installed, particularly the Adaptive ability. Powercommander makes no claim of Closed Loop adaptation within its module. Also, the Limp function of the Motronic is enabled when the O2 sensor input is disconnected. This means the pulse stream going into the PC III will have the 10% variation I wrote about a couple posts back.

 

The PC III looks pretty straight-forward to install but you do have to disconnect the O2, add two connectors to each injector, and install a piggy-back onto the TPS connector. So I would say it's fairly invasive to the Motronic system--if that matters to you. The PC gets its throttle position information from the TPS piggy-back but doesn't seem to have a TPS learn function like the Motronic. The PC III gets its RPM information from the injectors by measuring the frequency of fueling pulses. That works well but during Overrun Fuel Cutoff, the PC III doesn't have an RPM input. I think that might be a nit, but I mention it.

 

At its list price of $495.95, it's about three times the cost of an LC-1 but it is a Plug and Play solution. In terms of software, it's not clear to me whether the PC III has the logging capability of the LC-1 which I see as an important diagnostic tool. All the AFR charts of this thread have been made using that capability. It does come with a good suite of software for populating and managing the fuel tables should you wish to adjust them.

 

motronicpc.jpg

 

pc1150map.jpg

Edited by roger 04 rt
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A further note on using the PC III for richening:

 

I mentioned that a simple way to use the PC III would be to program the Wideband O2 that comes with it to (say) 13.8:1 and fill in the fuel table with 6% (maybe tapering to a lower number at the high RPMs and high TPSs). However, 6% is only the right number if you're running pure gasoline.

 

Since I haven't seen any documentation on the PC III's Closed Loop capability and haven't measured it; and since the Motronic's Closed Loop ability (and therefore its Adaptation capability) is disabled by a PC III; I believe that the fuel table should have 10% added for motorcycles that run E10 fuel. That would be 4% for E10 and (say) 6% for the richer Lambda setting on the Wideband O2.

 

The PC III may incorporate Adaptation capability but it may not. Many PC III installations don't seem to have Closed Loop but, from the software I've downloaded at their site, the 1150 has a Closed Loop function.

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I looked at the PC and the Techlusion and decided not worth it, to me anyway. I'm happy with my homemade booster plug and increased fuel pressure regulator. Couldn't ask for better performance. Oh, I bought a 3.5 BAR regulator but I think there is also 4 BAR unit that is used on a late model R1200. I'll stick with the 3.5 BAR. Still like the yellow ccp. Also, use an AP3923 primary plug with a one range hotter secondary NGK. Both plugs run dry and slightly dark, just right.

Edited by JamesW
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The PC gets its throttle position information from the TPS piggy-back but doesn't seem to have a TPS learn function like the Motronic.

Just FWIW the PCIII does indeed have a throttle position learn facility. It is not automatic though and must be activated while you have a laptop connected.

 

 

Many PC III installations don't seem to have Closed Loop but, from the software I've downloaded at their site, the 1150 has a Closed Loop function.

Their model naming conventions are a little confusing, there is the standard PCIII USB model with no O2 sensor (and thus no closed loop) and the PCIII Wideband (for BMW models) which does have a wideband O2 sensor.

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The PC gets its throttle position information from the TPS piggy-back but doesn't seem to have a TPS learn function like the Motronic.

Just FWIW the PCIII does indeed have a throttle position learn facility. It is not automatic though and must be activated while you have a laptop connected.

 

 

Many PC III installations don't seem to have Closed Loop but, from the software I've downloaded at their site, the 1150 has a Closed Loop function.

Their model naming conventions are a little confusing, there is the standard PCIII USB model with no O2 sensor (and thus no closed loop) and the PCIII Wideband (for BMW models) which does have a wideband O2 sensor.

 

Thank you for the feedback. I went back and reread the PC III manuals and installation instructions and found the Set-Up tool that let's you calibrate the TPS to the PC III, as you said. The installation instructions leave the O2 disconnected so the Closed Loop is function is within the PC III and their documentation doesn't mention long-term Adaptation.

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Yes, the PCIII Wideband model does disable Motronic closed-loop and substitutes its own closed-loop control (as I described earlier in the thread.) The manual isn't very technical (certainly nothing at the low level that we're interested in) and most of what I've learned has come from conversations their tech staff (actually their first-line tech support can't give you much engineering detail but you can get to the right guys if you're patient.) I never asked about whether the PC could maintain fuel trim info but I rather doubt it.

 

The PCIII is not inexpensive and probably overkill if all you want to do is richen things up a bit at part throttle (which is all the oilheads really need) but once you pony up it does have a lot of nice features if you want to tune the fuel map precisely, or want to have true (plug-and-play) closed loop control. I just don't like the way the Techlusion does things pretty much in the blind, but if you don't mind fiddling with them they seem to do the job.

 

And BTW, the Power Commander software does more than it seems (by just starting the software on a computer) as additional info appears once the computer is actually connected to the PC, such as real-time readout of A/F ratio, etc. But alas as far as I'm aware there is no logging function.

 

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...I just don't like the way the Techlusion does things pretty much in the blind, but if you don't mind fiddling with them they seem to do the job.

 

I have the same reaction to the Techlusion product. Here are some notes I prepared that go along with the block diagram.

 

Another method for richening the mixture is through the use of a Dobeck Engineering product. I'm aware of a couple: one disables Closed Loop (Techlusion) and the other allows Closed Loop in part of the RPM range (Electronic Jet Kit). Both products use the same technical approach of monitoring the injector electrical pulse. By measuring the time between injector pulses and their inection-on-time, the Dobeck technology can approximate the Load and RPM of the motorcycle. Neither product employs a Wideband O2 sensor like the LC-1 or PC III (although a gen 4 version does use a Wideband O2, I don't see it listed for the 1100s or 1150s).

 

The rider can then add fuel (lengthen the pulses) using three/four rotary dials (or plus/minus buttons) that allow different amounts of fuel to be added in cruise, acceleration or WOT. For me, the challenge of this approach is you can't specify how much fuel to add with a concrete setting (e.g. you can't specify 4% more than Closed Loop), and their is no Closed Loop monitoring of the result of the adjustment. However, with skill, I'm sure it can be made to work--provided that Closed Loop is disabled. With Closed Loop disabled, the fueling additions are made to the Limp Home pulse train with its 10% fueling variation that I showed a few posts back.

 

Looking at the block diagram below, the Narrowband sensor to the Techlusion but there is no indication in the documentation that suggests the O2 sensor signal is used to calculate the fueling addition:

 

motronictech.jpg

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Below are plots of Motronic Ma 2.4 injection times. The top plot is Injection vs RPM and the bottom is Injection vs TPS. I've added these to the thread as a reference. Looking at them:

 

1) The injection time increases with increasing throttle opening. So as you want more acceleration, it adds more fuel.

 

2) The injection time stays fairly constant when compared to RPM. In the crusing range between 2000 and 4000 RPM, injection times are 2 to 3mS (thousandths of a second). This means within that range they are on for somewhere between 6% of the time and 20%.

 

3) At WOT and 7250 the injectors are on roughly 100% of the time--8.1mS on pulse and 8.2mS time between pulses.

 

4) There are no Zero pulses (Overrun Fuel Cutoff) below 1800 RPM.

 

5) There are no Zero pulses above a couple degrees throttle opening. Taking point 4 into account OFC kicks in during deceleration when the throttle is below 2 degrees (idle is 0.32 degrees) and until RPM is below 1800 RPM.

 

injectionscatter.jpg

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  • 4 weeks later...

I've been doing some further research on the Powercommander III for Oilheads and now have a much different view of how the PC and Motronic work together. My prior view that the PC didn't drive the Motronic's O2 sensor input was wrong and was due to a lack of documentation. But that said, here is an update for those interested:

 

I've heard from Dynoject and although I'd like some further clarifications, I don't think I'll hear more. The product was designed nearly 10 years ago and as you would expect the designers have moved on.

 

" the testing was done so long ago I may not be able to answer your question thoroughly."

 

The BMW Powercommander III USB Wideband is essentially a Wideband Commander coupled to a Powercommander III USB.

 

The essence of what I've heard fro Dynojet is:

 

"The connection to the stock ECU narrow band input is tied to our Wideband sensor. We are able to offset the narrowband signal based on our wideband input."

This is how the Innovate LC-1 works, although the LC-1 is a later, better performing design with data logging capability.

 

The BMW Powercommander and Motronic runs closed loop and develops Adaptation values everywhere the Motronic would on its own. That's because the Wideband signal, converted to narrowband format, is "Always connected". The shaded area on the PC fuel map (see photos several posts back) is just a guess on PC's part about where the Motronic is in closed loop.

 

"The highlighted area is what we have interpreted as the closed loop area of the stock ECU."

 

I have many measurements that show the closed loop area of the Motronic is up to 62.5% throttle and up to 6250 RPM. I think we should expect that it is closed loop everywhere below those numbers.

 

I did some digging and found letters from Dynoject to Harley forums where there was a clamor for this capability. Here is part of what the design manager wrote:

 

"Let us start with why the BMW uses a wide band O2 sensor as part of the unit. The bike already has a "closed loop" circuit as part of the OEM injection system. It does not "auto map" the entire rpm/throttle position range of the fuel map. Generally speaking, the closed loop system only adjusts the fuel curve below 40% throttle. Above that the system is "open loop". The new Wide Band BMW unit only controls the stock "closed loop" area. Outside of that the bike is mapped in the normal fashion, on the dyno.

 

We would actually prefer not to maintain the closed loop section. Due to the design of the OEM injection system it is not possible to bypass it as we do with other models. Closed Loop systems are not the "magic" that most people believe they are. There are a number of problems that keep it from being the best choice for high performance applications."

This all means that the PC III for USB works very differently on an Oilhead than on any other motorcycle most Dyno tuners work on. It also means that the WOT "pulls" aren't likely to provide an optimal tuning since most dyno tuners don't seem to understand the interaction with Closed Loop Adaptation Values. There's no reason that they should be familiar since this product works differently than most every other PC they would work with.

 

With this information, it is now pretty clear to me how the Powercommander and Motronic work together. My plan is to update the block and show a recommended fuel map for implementation. I am a lot more positive on the Powercommander as a tool now than before. It can be implemented on the majority of BMW Oilheads with NO Dyno tuning.

 

If anyone reading this would like to loan me a PC for a couple weeks I'd like to run some tests. In the meantime I'm going to try and buy one used. Then later I'll resell it, all set up for installation.

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Roger just want to say thanks for all your research here. Even though there aren't a lot of comments I'm sure there are many who are following this thread with interest and I know your efforts and detailed posts are being greatly appreciated.

 

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You say the PC makers argue that for a sporty bike, riding on an open-loop table leads to better performance. I agree with that and agree with Tom Cutter that BMW spent a fortune in testing time to develop a good map.

 

And the only influence the PC has is by substituting its fudged O2 signal to the Motronic (based on a short-lived and expensive wide-band sensor). This fudged signal can only influence the Motronic's fueling during those periods when the Motronic has chosen to run closed-loop (not over 62% throttle, not just after the throttle has been jiggled, not at very low throttle or idle....).

 

So why not just disconnect/disable the stock O2 sensor and force the Motronic to be open-loop all the time so you don't need a PC? (Assuming the health of your cat converter, if any, isn't an issue.)

 

Or just broadly but mildly enrich using a Techlusion or use a simple O2 sensor scaling circuit?

 

Ben

Edited by Peter Parts
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I think it's interesting that PowerCommander III for Oilheads includes a Wideband O2 for Closed Loop with the Motronic; and PowerCommander V for the R1200s includes a Wideband sensor for tuning but not for Closed Loop.

 

The engineers at Dynojet realized that the Motronic doesn't run it's best without an O2 signal and added the Wideband. The reaction of the Harley crowd at the time (2004) was to petition Dynojet to make a Wideband PC III for Harley's. The problem Dynojet was trying to solve is that the Motronic MA 2.4 (and probably 2.2) goes into "limp home mode" (LHM) when deprived of an O2 signal.

 

Many believe that LHM on the Motronic is richer. What it actually does is vary the mixture about 5% leaner and 5% richer than gasoline 14.7 in an attempt to keep the catalytic converter charged with oxygen. That means the approximate Open Loop fueling swings are 14.0:1 to 15.4:1 while cruising with no O2 connected. If you run E10 fuel with no O2, the mixture varies from about 14.6:1 to 16:1. It's tough to tune in the presence of a 10% swing. So they added a Wideband sensor and allowed the Motronic to run in Closed Loop. And to make it interesting, the only documentation they provide is to say--connect our cable to the O2 input.

 

BTW, the data I've taken shows Closed Loop in the presence of throttle motion, during acceleration once the throttle movement has slowed, at idle and even cruising at 100 mph. It is Open Loop during warm-up, over 60% throttle (>48 degrees from what I've seen so far) and during large throttle movements.

 

I'm in the process of updating the Motronic/PC III Wideband block diagram and will have some more comments then.

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I think that the 2.2 Motronic simply looks for the presence of a CO potentiometer when it doesn't see an O2 sensor and a cat code plug. Also, I think the 2.2 Motronic has a fueling map (European) that is activated when no code plug is detected. In the case of the 2.4 Motronic if you remove the code plug what you refer to as "limp home mode" is activated and this mode of operation does not produce ideal fueling and is intended as a temporary condition only. Therefore, the 2.4 Motronic must see a code plug or proper fueling will be inhibited. So, I guess what I am saying is I don't think the 2.2 Motronic has a "limp home" mode. Also, when the O2 sensor is disconnected the 2.4 Motronic does not look for the presence of a CO potentiometer but rather remains in open loop with inputs from the other remaining sensors used to determine the fueling mixture. So, the long and short is I think the 2.2 does not have a limp home mode only the 2.4 does and I'm not at all sure why the difference. I also think there may be differences in the 2.2 Motronic beginning with production in 1996. My experience with the 2.2 Motronic is limited to my observations and experiments to my '94 R1100RSL which was produced in 06/93. I operate my '94 R1100 with the code plug jumper removed and a CO Potentiometer (9 turn 1K POT) connected and O2 sensor disconnected basically a European configuration. With this set up I get no surging and a 13.5/1 air/fuel ratio as measured on a dynamometer at Big Twin BMW of Boise, ID.

 

Early on when my '04RT was less than one year old I tried removing the code plug like so many R1100 owners had done with good results. I quickly replaced the code code plug (pink) as it was obvious removal did not result in improved operation in the '04RT at all! My nose told me that without a code plug the mixture had become extremely rich and over the road operation resulted in very loud periods of backfiring. One short ride was all it took and the code plug was re-inserted posthaste.

 

In the case of my '04RT with the 2.4 Motronic I performed the Rob Lentini zero-zero adjustment to the throttle bodies as described on the IBMWR web sight just to see what would happen and I am very pleased with the result especially at idle. I have never seen a 2 cylinder motor idle so smoothly. I know the 0/0 procedure is recommended for the R1100 but I thought it should work just as well on an 1150 and in my case it certainly did. I set the TPS at .390 volts. I also constructed my own booster plug (AIT sensor) and installed a later fuel pressure regulator to increase pressure by about 7 or 8 psi. Also, I have disconnected the O2 sensor to avoid closed loop operation. I would install an LC-1 with wideband sensor but my computer is a Mac and is not compatable with the LC-1 otherwise I would be using the LC-1. Oh, I settled on a yellow CCP after experimenting and test riding with the other configurations. Fuel economy varies between 43 and 51 mpg depending on variables like terrane and wind speed/direction.

 

Long and short is I am very satisfied with both my oilheads as they are configured. I must confess however, that I kind of wish I owned a pc. :)

Edited by JamesW
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Afternoon James

 

The 1100 (Ma 2.2 system) doesn't look for the CO potentiometer when it doesn't see an O2 sensor present.

The CCP (coding plug) determines IF the Ma 2.2 uses a Co pot to fuel to at idle or not.

Actually it (the Ma 2.2) only uses the Co pot when CCP terminals 30 to 87 are open.

So, no CCP fulfils that open between 30 & 87, as well as the light green CCP (no 30 to 87), & light Brown CCP again no 30 to 87).

I don't know how your 94 Ma 2.2 system fits in here as that has no CCP but has in-harness jumpers.

 

On the 0=0 for the 1150 MA 2.4 system. --0=0 really does no good on the Ma 2.4 system as the 0=0 is used to skew the air flow through the throttle plates vs TPS voltage seen by the Motronic. Seeing as the Ma 2.4 uses a LEARNING TPS when doing the 0=0 procedure on the MA 2.4 system any gain is negated as soon as the 2.4 re-learns the TPS low & high threshold as the air flow vs voltage skewing is right back to where it was before the 0=0.

 

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Hi D.R.,

Yes, the in cable jumper which I cut produced a yellow code plug configuration according to the factory manual I have for the '94 R1100RS. Maybe I didn't have to actually be concerned with this jumper but the factory manual showed a set up without code plug and the jumper simulates a physical code plug which is missing in the European configuration. I'm fortunate the motorcycle came with the factory manuals or I would have had problems as the schematic in my Haynes manual is very different for the R1100RS. That's what makes me think the 2.2 changed in 1996 and is different from the early version.

 

The 2.2 Motronic doesn't learn the limit points of the TPS as does the 2.4 but it seems to me the end result is the same in that both Motronics recognize the TPS limits and apply this data in the same fashion. The 2.4 apparently stores these limits in memory and this memory must be cleared in order recognize a new set of limits whereas the 2.2 doesn't have a memory that must be cleared and then new data entered but the end result, after re-entering the new limit data, is the same in both the 2.2 and 2.4 units. Hope I'm making sense here. In other words both Motronics use the same TPS output in the same fashion to perform the same purpose. Therefore, why wouldn't the 0/0 procedure also function the same with both units? Just that one system stores the TPS limits data in memory and the other always looks at the raw data as it comes directly from the TPS. I hear what you are saying but I just can't see it. Nor can I see why the difference between the 2.2 and 2.4 Motronic.

 

I wish Bosch offered a seminar on Motronic theory of operation because I would pay to attend.

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Earlier in this thread I presented an incorrect explanation of how the Power Commander III USB with Wideband O2 operated when integrated with the Motronic MA 2.4. The reason for this error was an omission in the Power Commander installation manual for R1150RT. Here is the correct explanation, please refer to the diagrams at the end of the thread.

 

The Power Commmander III with Wideband O2 for BMW R1150 and R1100 is actually two different functions in one package. One function is that of the Power Commander III USB an Add-On Fuel matrix of values according to RPM and TPS. The second function is much like that of the Innovate Motorsports LC-1. Rather than recapitulate the Add-On Fuel function you can read about it here: Power Commander III USB .

 

The second function, Wideband O2, functions just the same as an LC-1 Wideband O2 controller. You can read about that in detail earlier in the thread. In short, you replace the stock Narrowband O2 sensor that has a fixed transition point at 14.7:1 AFR (actually Lambda = 1, meaning that theoretically all the oxygen has been consumed) for a Bosch LSU 4.2 Wideband O2 sensor which has a programmable transition point. By selecting a Lambda value less than 1, the Motronic will automatically richen the mixture in the Closed and in the Open loop fueling calculation. I'll rephrase that: if you drop Lambda to 0.94 the Motronic will run Closed Loop at 13.8:1 which is 6% richer than stock 14.7:1. Then through the magic of the Motronic's Adaptation Values capability it will also add fuel to all Open Loop fueling calculations after a "learning" period.

 

The "learning" period takes some time and is not quite perfect because you have to drive your motorcycle at steady throttle for enough time in Closed Loop at a range of throttle openings and RPMs for the Motronic to "learn" the full adaptation map. It is likely that there are fewer Adaptation Values than cells in the Base Fueling Table of the Motronic, which means that there is likely a coarser correction. But I've measured it, and Adaptation works effectively, it just takes a while. The bigger the shift in Lambda that you're making, the longer it seems to take to "Adapt".

 

There is a way around the "learning" time. In short, find a way to either a) add a percentage of time to the pulse coming from the Motronic; or b) increase the fuel pressure so that the pulses coming from the Motronic deliver a percentage more fuel than stock. Since the Innovate Motorsports does not have an Add-On Fuel map I added a Fuel Pressure regulator and boosted the fuel pressure. However, if you use a PC III USB, you can add the fuel through the fuel table function.

 

Looking at the sample Add-On fuel tables below, if you fill in the fuel matrix with a 6% addition in every cell at 60% throttle and below, and then reduce to 4% more fuel at 80% throttle and 2% fuel at 100% throttle you will have a sound starting point. Note that this approach acknowledges the great work that BMW has done in their design of the Base Fuel Map in the Motronic; it just adds a proportional percentage to account for the amount of richness you want to add. I'm sure this seems like a simplistic use of the Add-On Fuel function of the PC III but it will work and you won't need to add a BoosterPlug or Fuel Pressure regulator.

 

I'll end with a short comparison of LC-1 and PC III. Both are technically sound methods for controlled richening of the Oilhead's mixture, leading to much better driveability and a bit more power in the mid-band (2000-5000 RPM) which it achieves by moving up the AFR vs Power Curve earlier in the thread. (There will not be an increase in WOT horsepower because the BMW fuel tables are already near Best Power Mixture there.)

 

Advantages LC-1:

--Lower cost: $170 for the LC-1, $395 for PC III (although I've seen PC III for $285)

--Calibration function for the Wideband O2 sensor

--Datalogging of the realtime stream of O2 readings

--AFR gauge included in purchase price. It is an add-on for the PC III.

 

Advantages PC III:

--Plug & Play: The PC III has all the connectors you need to plug it in out of the box. For the LC-1 you need to wire your stock O2 sensor connector and also power leads to its cable.

--Built in Add-On fuel capability. If you use the LC-1, you either wait for Adaptation, add a BoosterPlug which shifts fueling a fixed 6% or, as I did, increase the fuel pressure. A good fuel pressure regulator costs around $100.

 

RB

 

Notes

1) I am trying to get a PC III w/Wideband but have not run one yet.

2) The fuel table on the PC III allows you to enter percent increase/decrease. Typical injectors have a 1 mS dead (on/off time), I don't know if the dead time is taken into account by the PC III.

3) At 7250 RPM the injectors fire every 8.3 mS. The longest injection pulse that I've seen is 8.2 mS. This points out that you can't add 5% to the longest pulses with making them longer than the frequency of rotation in some cases. (However, the vast majority of the time injection pulses are less than 4 mS.)

4) I don't think there's a problem but I can't tell how the PC III responds to Overrun Fuel Cutoff when no pulses occur (i.e. the PC III isn't getting any engine speed info during that time.)

 

motronicpc1.jpg

 

pc3gasoline.jpg

 

pc3ethanol10.jpg

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Afternoon James

 

We are starting to step on Rogers 02 sensor thread here so I will respond to your questions if you start another thread on this.

 

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The second function, Wideband O2, functions just the same as an LC-1 Wideband O2 controller. You can read about that in detail earlier in the thread. In short, you replace the stock Narrowband O2 sensor that has a fixed transition point at 14.7:1 AFR (actually Lambda = 1, meaning that theoretically all the oxygen has been consumed) for a Bosch LSU 4.2 Wideband O2 sensor which has a programmable transition point. By selecting a Lambda value less than 1, the Motronic will automatically richen the mixture in the Closed and in the Open loop fueling calculation. I'll rephrase that: if you drop Lambda to 0.94 the Motronic will run Closed Loop at 13.8:1 which is 6% richer than stock 14.7:1. Then through the magic of the Motronic's Adaptation Values capability it will also add fuel to all Open Loop fueling calculations after a "learning" period.

 

How does the Motronic calculate an adaptation value for an area in the map where closed loop operation never occurs? With no actual data, there is no basis for selecting one value over another. Do you have a reference that explains how this is done?

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The second function, Wideband O2, functions just the same as an LC-1 Wideband O2 controller. You can read about that in detail earlier in the thread. In short, you replace the stock Narrowband O2 sensor that has a fixed transition point at 14.7:1 AFR (actually Lambda = 1, meaning that theoretically all the oxygen has been consumed) for a Bosch LSU 4.2 Wideband O2 sensor which has a programmable transition point. By selecting a Lambda value less than 1, the Motronic will automatically richen the mixture in the Closed and in the Open loop fueling calculation. I'll rephrase that: if you drop Lambda to 0.94 the Motronic will run Closed Loop at 13.8:1 which is 6% richer than stock 14.7:1. Then through the magic of the Motronic's Adaptation Values capability it will also add fuel to all Open Loop fueling calculations after a "learning" period.

 

How does the Motronic calculate an adaptation value for an area in the map where closed loop operation never occurs? With no actual data, there is no basis for selecting one value over another. Do you have a reference that explains how this is done?

 

A couple things:

 

I should have added a comment in the Notes section of that post to the effect that the shaded area of the Map attachment above is only Dynojet's estimate of the Closed Loop area. I have data that shows Closed Loop operation up to about 6500 RPM and up to about 50 degrees of throttle out of 80 which is about 60%.

 

I have measured Warm-Up, WOT and other Open Loop values as having been Adapted. As far as the algorithm, I don't know it exactly for the motronic but have read descriptions a few places, they're all similar, I'll try and find one for you. The idea is that the Motronic compares it's Closed Loop calculation of injector-pulse-width to its Open Loop calculation. Close Loop operates over a large fraction on the map, at higher RPMs and throttle angles I've read that the usual approach is the extrapolate from the nearest values. So if 50 degrees throttle had a +3% Adaptation it might carry that amount to 60, 70 and 80 degrees, as an example.

 

The main purpose of Long Term Adaptations is to calculate corrections that take cylinder dynamics, fuel pressure, fuel flow, air flow, fuel ethanol content, etc. into account. One of the big side benefits of having an O2 sensor for controlling mixture for the catalytic converter is that it can create Adaptation Values.

 

EDIT

If you google Long Term Fuel Trim you can find some other references. Here is an example: Long Term Trim Explanation . There are others. I remember that Bosch/BMW sometimes use percent trims and sometimes use additive/subtractive values depending on RPM. On our Motronic MA I know it occurs and have measured it but I've not found the formula.

Edited by roger 04 rt
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Roger,

 

Those are all good references, but they still don't really answer my question. I understand how long term fuel trim is calculated and applied in those regions of the map where closed loop operation takes place. I also understand that LTFT is applied in those regions even when the engine is operating open loop. But none of the references provide any concrete evidence that LTFT is applied in regions where the engine only operates open loop and never uses O2 sensor feedback,

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Roger,

 

Those are all good references, but they still don't really answer my question. I understand how long term fuel trim is calculated and applied in those regions of the map where closed loop operation takes place. I also understand that LTFT is applied in those regions even when the engine is operating open loop. But none of the references provide any concrete evidence that LTFT is applied in regions where the engine only operates open loop and never uses O2 sensor feedback,

 

Karl,

You'll have to look around some then but you will find it. One of the most valuable places to apply Long term trim is 80 and 100% throttle and systems are never Closed Loop near WOT. If the long term trims weren't applied at WOT you could have a lean mixture due to E10, low fuel pressure or flow, etc. just when you wanted the mixture to be on target.

 

If you look at the table here you will see examples of the trims that extend up into the WOT range, e.g. 77%+ kPa, 2200+ RPM.

 

I've measured it on my motorcycle so I know it exists. But it is disappointing how little clear info is out there, BMW/Bosch treat their EFI info like a state secret. If I come across something I'll add it.

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If you go to the detailed write up in the middle of this explanation of GM's system you'll see this equation:

 

BPW = BPC * MAP * T * A/F * VE * BVC * BLM * DFCO * DE * CLT * TBM

 

And BLM is the long term trim. It is part of the basic Open Loop fuel calculation (including WOT and warm-up)

 

Later it explains:

 

"BLOCK LEARN – Block Learn is a term that is related to closed loop mode, but continues its influence during all modes."

 

Granted this is for the GM system but since Bosch is secretive we have to learn about these things other places and confirm the behaviors by measurement.

Edited by roger 04 rt
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While the equation may be used everywhere in the map, not all terms have a non-zero value everywhere. The discussion in the article about BLOCK LEARN states that "Over time, the BLM numbers will settle at a value that gives a 14.7 A/F ratio with no closed loop term correction." To do this, BLOCK LEARN needs to know when an AFR of 14.7 has been reached. The ECU cannot do this in areas of the map that are always open loop, since O2 sensor feedback is not used in these areas.

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Right it does that in the Closed Loop area but the applies the "learning" in "all modes", and where it is most import, at WOT. And in any case, I've measured it happening.

 

 

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With all the variables in the equation, how can you really tell that there is an adaptation at WOT?

 

Good question, and skepticism has been important as I've tried to coax the Motronic into giving up its secrets.

 

If you were to read some of the other articles on the carprogrammer site and work down to this article, here, you would come to this next part which talks about BLM 15 the WOT BLM.

 

... Your BLM cell 15 used in WOT was actually learned under a non-WOT condition, not representative of WOT at all. ...

 

Taking a different tack, let's assume there was no BLM for WOT, and the target afr in the fuel table was 12.8:1. With no long term trim, as soon as you put E10 in the tank, WOT would be 13.3:1. Then say your fuel pressure was 6% on the low side. Now your WOT would be 13.7:1. Then go one more small step and your injectors were on the low side and a bit dirty and were 4% low. Now your WOT afr would be 14.2:1. You see where I'm going. It would be unquestionably bad.

 

Still, if you were to believe that WOT was not influenced by long term trim then anyone who runs E10 should install a 3.5 Bar fuel pressure regulator, and everyone should clean injectors periodically and check fuel pressure annually. Luckily, because of long term trims which come for free with a learning, closed loop ECU, we don't have to do that.

 

RB

 

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