Understanding the operation of the Motronics 2.4 ECU

[AirForceDirt]

Then whats the extra ticking noise at low revs and full open throttle?

Uh...

Knock?

Knock would sound like a ticking? a moderately louder tick than the spark plugs firing? At nearly the same frequency and perfectly in time with said spark plugs? Isn't knock when the gas is pre-combusted, not combusted at the right time? That seems like normal combustion to me. And then why is it only heard through the electrical system? I've heard a car engine knocking, and I know its got bigger parts but still, it was much more noticeable.

[Sunbeemer]

Maybe the secondary plug's firing is triggered by the Motronic solely off rpm and throttle position, for example under hard acceleration from low rpm the program triggers the secondary sparkplug to avoid predetonation (knocking). This would allow more complete burns of enriched air/fuel mixtures, and reduce emissions without CCP mapping.

[AirForceDirt]

Maybe the secondary plug's firing is triggered by the Motronic solely off rpm and throttle position, for example under hard acceleration from low rpm the program triggers the secondary sparkplug to avoid predetonation (knocking). This would allow more complete burns of enriched air/fuel mixtures, and reduce emissions without CCP mapping.

That makes more sense. Wonder who designed this thing, or if the service guys who fix them are supposed to know. Might swing by the dealership in the morning and ask one, see if he knows.

[boxermania]

Gentlemen......if the Motronic 2.4 doesn't have the smarts for a MAP sensor, rest asured that it will not have any fancy algorithm to fire a secondary spark plug as a result of combustion efficiency. Based on the smarts of the Motronic and the plug location (they straddle the combustion chamber at about the same location, the only diference being the angle of entry) Maybe there is a slight firing delay of the second plug, something in the low, low milliseconds to potentially extend the light off time of the flame in the combustion chamber, although I seriously doubt it.

First the noise (ticking) might be the left cylinder chain tensioner, if your bike is prior to the 04' model. I seriously doubt you can hear a spark plug fire.

AirforceDirt
I understand what you mean about the O2 sensor being so far away. I still think that, even without the ccp, its still active.

Regarding the quote above, it should be easy to find out, there are four wires out of the O2 sensor, 2 power and 2 signal, with a scope you can check each wire to ground with the CCP on and off......

As far as the PC, it can accept the input of a wide band O2 sensor which will improve the overall response of the engine, unfortunately our engines have the narrow band O2 sensor (read inexpensive and slow). The basic functionality of the PC is that it can both add (richen) and reduce (lean) the firing time of the injector as directed by the Motronic, as a comparison the Techlusion is a far simpler device that can only add time to the injector firing as the added time is allocated based on three ranges of operation low, mid and WOT just lke a typical motorcycle carburator.

Since or bikes run on the lean end of the spectrum and don't have the smarts, IMO, the Techlusion is a better and less expensive enhancement, however, the least expensive solution, albeit not the easiest to implement, (tedious) is to swap the stock 3 Bar fuel pressure regulator for the 3.5 Bar used on the previous generation K bike, I bought mine from Chitown BMW for $36 and is a direct replacement.....it does change the character of the bike.

In closing.....AirforceDirt.......yes, that would be an eye opener, swing by the dealer and ask away, it can go either way, but at least you will know who to deal with.......good luck

[Jammess]

A question: What does the output from the oxygen sensor look like? Is it a varying DC voltage or is it a pulse like maybe that produced by a 555 timer IC? Reason I ask is I would like to try and build a simulator that would fool the ECU into thinking it has a valid sensor input that is always constant. Seems to me this would eliminate surging. Also, does our sensors operate with heaters? If so one could sub a simple carbon resistor for the heater.

[riceburner]

So when does the second plug fire? Or is it always firing? Then whats the extra ticking noise at low revs and full open throttle?

I understand what you mean about the O2 sensor being so far away. I still think that, even without the ccp, its still active.

Looked up the power commander for the R1150....and the reason why its so damned expensive: Its a wide band (unlike, apparently, the normal sport bike PCs) which makes it much more versatile. Not sure if its worth $400 for what it'd do. It might help if one were to install the Boxer Boost cams from Wunderlich.

My understanding is that the CCCP just switches between different fuelling maps within the motronic. The default one is what you get with no CCCP, and the other ones (like the Californian lean burn map) you get with different cccp plugs.

[riceburner]

Maybe the secondary plug's firing is triggered by the Motronic solely off rpm and throttle position, for example under hard acceleration from low rpm the program triggers the secondary sparkplug to avoid predetonation (knocking). This would allow more complete burns of enriched air/fuel mixtures, and reduce emissions without CCP mapping.

The 2nd plug is ALWAYS firing.


want to proove it? pull the primary plug cap off, and start the bike - it'll run - it'll be a bit rough - but it'll run.

[AirForceDirt]

Know if you can wire a wide band O2 sensor into the system?

[boxermania]

Jammess
It's a continously varying DC voltage with very little use in raw form (kinda like a signal with a lot of white noise).....it has to be averaged over a one second span, in our case, to be of any use. I'm refering to the narrow band O2 sensor used the R1150R engines. It has 4 wires, two to power the heater element with 12 DCV and 2 for the ~ 0 to 1 VDC signal out.

Your process of thought hs some validity because if you offset the voltage output it will inrease/decrease the A/F ratio.....the problem is that the system cure is very steep and a small chnge in voltage will produce a large change in A/F ratio. I have enclosed a link for your review.

http://www.aa1car.com/library/o2sensor.htm

In your case you are better off placing a resistor in parallel with the ambient air sensor, easier and the same result. I'll dig up the Resistenace/Temperature curve I generated and post it.

AirForceDirt
I think you can, at least electrically, the question is if the Motronic 2.4 can process the signal??

[AirForceDirt]

AirForceDirt
I think you can, at least electrically, the question is if the Motronic 2.4 can process the signal??

I meant if one were to hook up a power commander and a wide band O2 sensor? Theorizing here. Would the PC be able to tell the Motronic what to do with the signal from the wideband O2?

[macx]

Although most heartily agreed that a system such as on the hex heads is superior, there is
a significant number of examples of a similar wasted-spark and "batch fire" injection in the major-mfg auto world.

Many of the more modern US coil-on-plug engines are "wasted spark".

I don't know about oem applications, but do know that a number of successful
"batch-fire" efi aftermarket systems have existed for some years and are in use in
sufficient numbers to demonstrate that the system works although obviously not as well
as a well engineered mass air sequential firing efi system.

There are a few aftermarket automotive systems available that are purported to be
adaptable to an engine of from 2 to 10 cylinders, but again not sure without reviewing
the info if any of them incorporate a catalyst into their management system, and
then if it's a narrow or wide band. Might have to do a little research just for s's & g's.
I do believe if memory serves that they still are speed-density, however, and require a
laptop to change tuning parameters which are then locked in and don't vary with
atmospheric changes other than within the 02 sensor driven minor adjustments.

I'm a big fan of mass-air type systems as opposed to the speed-density type which
ours is, having worked fairly extensively with mass-air on modified auto engines and
seeing first hand how adaptable and tuneable they can be to work very well with a
variety of engine modifications as well as with virtually any popular engine brand and
configuration. Too bad none of those are 2 cyl's though. On my car, I've got a wide-
band monitor (can even do data-logging for tuning purposes) and a device that actually
reads all the existing tables in the computer and can over-ride them via a laptop as long
as the device is plugged in, or the info can be used to burn a new chip. I've seen these systems used on a wide variety of engine displacements of different brands with great success, unfortunately, however, they're all 6 or 8 cyl.

Too bad it would be such a major problem adapting the hex head system, but then the
fuel and spark maps probly would be too far removed from optimum given the difference
in displacement and cam design to run properly anyway.

Sounds like we're sort of backed into a corner where a few tweaks, i.e. via a techlusion,
or the intake temp resistor or higher fuel pressure which are across-the-board constant changes as opposed to reacting to different ambient conditions only when needed,
is about the extent of the improvements we can readily make.

[Jammess]

Thanks Boxer, good write up on how the O2 sensor does its thing. I am thinking of using a multiturn pot with +12VDC on one end and ground on the other with the wiper connected to the sensor input of the Motronic. I would leave the O2 sensor installed and connected just to maintain continuity for the heater circuit. Not sure how the Motronic would react if the heater were disconnected. I would start by just picking off about .350 volts. Not sure if fooling with just the air temp sensor would have much affect as far as surging goes because the O2 sensor would still be sending a varying signal to the ECU. I have a Techlusion installed and it does improve and smooth out performance. I think my issues began about 2 years ago when one or maybe both of my stick coils began to malfunction. When this happened my '04RT began to surge hence the Techlusion. The condition became worse when both stick coils became unable to fire the primary plugs when they were gaped at .032 inches. When this happened I knew it was time to do some serious troubleshooting. Didn't take long to determine both coils had failed. The interesting thing was they would fire the plugs if the gap was reduced to .020" or less. I was surprised by this as I thought the coils would be go no-go in nature. My theory is that these stick coils fail because of a tendency to arc over to the internal static shield that is grounded by way of the center pin of the 3 pin connector used to apply the switched 12 volts to the coils. I clipped the brown wire on each 3 pin connector thus removing the ground from the static suppression shields on both stick coils to hopefully prevent a high voltage carbon trail producing path to ground. I could care less about having a static shield on my coils because I don't have a radio. One of the bad coils had a measurable 10 Meg resistance from the high voltage terminal to the center pin of the 3 pin connector no doubt proving the presence of a carbon trail to the internal static shield. Long and short is I plan to use the multiturn pot to simulate the O2 sensor and disconnect the Techlusion as I doubt it will be needed.

Would be interesting to know how many perfectly good stick coils were destroyed by this grounded internal static shield. Bet my new coils last a long time with the static shield ground connection removed.

This is somewhat off subject but another theory which I think is bunk has to do with the Autolite 3923 plug and its magical ability to eliminate surging better than an NGK plug. The AP3923 is simply a hotter plug than a heat range #7 NGK which is what is recommended for an R1150. So just drop in a heat range #6 NGK and you will no doubt get the same performance as that obtained with the mystical 3923.

End of off subject crapola.

[boxermania]

macx
Your points are well taken, manufacturers will tend to use the simplest systems unless they have a reason to do otherwise. Most recently we have seen a shift to sequential and direct injection, which obviously they have vastly improved the breed.

If you are a tinkerer, there are a few things that can be done to our systems to improve the operation of the engine, unfortunately and as you so aptly indicate we are dealing with an older and less capable system.

I've always wondered about the typical A/F ratio of a stock R1150R during operation with and without the CCP. That would be taken as a baseline to define avenues to explore. I do have an Innovate LM1 with the wide band O2 sensor and RPM module, which unfortunately I came about after I sold my bike. I would be willing to loan it to someone with the required understanding and skill set to obtain the engine A/F baseline.....after that the options are varied.

Jammess
What you propose to do is a bold approach and I can't find an objection, other than A) I hope you can monitor the voltage in real time and B) Insure the variable resistor (pot) can provide small voltage changes. Remember the curve between rich and lean is quite steep.

I'm troubled by your comment that with all plugs in operation and the addition of a Techlusion the engine is not smooth and sans surging.......air filter and most important TB's sync in good order????

In respect to the Autolite 3923 and their "magical ability to suppress surging" I must confess this is the first time I heard the statement. The AP3923's claim to fame was that they were less costly replacement to the original two prong NGK plugs with no apparent performance decay. Regarding the heat range, if correct, I would hesitate to use a hotter plug on an engine that is already running on the lean range (high combustion temps) to begin with.

[Jammess]

Been thinking about my multiturn pot O2 sensor simulator and to really do it up right I will have to construct a simple to build DC to DC voltage regulator with a 12 VDC input and about a 1 or 2 VDC output to my multiturn pot. that way the voltage I send to the ECU will be spot on and ulta constant. Also, when I set the pot wiper at the .350 VDC output point the 10 turn pot wiper will be at the midpoint or about 5 turns from either end. Will be a fun little winter project.

James

[boxermania]

Jammess

I think is very much doable....I will sugest that you monitor the voltages on the sensor circuit of the existing O2 sensor for reference. You might want to refer to my recent post on this forum dealing with Bosch O2 sensor replacement.

I further believe that you could potentially splice onto the output of the O2 sensor going to the ECU.

Keep us posted on your progress.

[Jammess]

Boxermania, when I first started having surge symptoms or problems which I now believe were caused by stick coil malfunctions I did replace the original O2 sensor with the Bosch replacement and the performance was unchanged which indicated that there was nothing wrong with the original sensor.

I have decided to go with a 1.8 volt zener diode for a simple voltage regulator. I have a project I must accomplish immediately, non motorcycle related, so I will not be able to do this project for awhile but I will keep you informed. I plan to start with.350 volts to the ECU and then make adjustments while closely monitoring the fuel economy. Then of course, winter is fast approaching if you know what I mean.

[Jammess]

Boxermania, when I commented about the AP3923 plug I was referring to the many threads by people who seemed to credit this plug to curing surge symptoms with their motorcycles. Some folks like the plugs because they are so cheap compared to the NGK and they are. I believe the AP3923 is about one range hotter than the recommended NGK and I believe this is the only difference other than cost. If someone thinks this AP3923 works better than an equivalent heat range NGK or Champion or whatever I say bunk!

By the way, I believe the ECU draws very little actual current from the O2 sensor. Would you agree?

[AirForceDirt]

I think in the coming months, I'm going to be spending a lot of time at the local race-sport bike shop playing with the 1150 on their dyno. I'd like to see the effects of certain things on the operation of the beast and in the end find the most stable, efficient operation while still maintaining the power and torque that I've come to expect out of the boxer. This is probably going to be a long and expensive winter.

[boxermania]

Jammess
The ECU provides 12 VDC to the O2 sensor for the heater and receives the 0 to 1 VDC from the zirconium cell as an input along with other inputs to control the A/F ratio during closed loop operation (steady state runing)

AirForceDirt
I like your way of thinking.

Gentlemen, please keep us advised. There always something new to learn. Good luck.

[Jammess]

Okey dokey, curiosity got the better of me and I ordered the parts to construct my o2 simulator today priority mail.

James