I am currently undertaking swapping out the stock Motronic ECU unit with a Microsquirt system. I have a good grasp at all the sensors and work involved. My issue is starting with a base map tune which I have not come across, well one that I think is a reliable start anyway. The map I found came from a forum where they convert the K series engine to run in a Mini Cooper. So it leaves me thinking that I can install the microsquirt as a “piggyback”, passively listen and capture all the values that are needed from the stock ECU and then tune from there. Does anyone have any insight to this insanity that I’m attempting

Can't help you at all with this but I am interested in tracking what you do/how you go about developing a new ECU.  Keep posting!

Most definitely!

I've been in the midst of collecting what I can scrape up from the deep webs and google cache archives. From my searches, it looks like a fellow 'bricker got his K running successfully a little less than a decade ago on a K75. Here's the start of the thread on Motobrick: https://www.motobrick.com/index.php?topic=936.0.

I've managed in the past day to get his tune files and other related project plans. I'm thinking I can port what he has done over to my K1100 to start as a base and go from there. It'll be interesting reviving an almost decade project for the K series. I'm got the Microsquirt V3 and donor harness in hand. The MAP sensor and wideband senor should be here this week. My weekend just filled up.

Keep us posted please.  I'd like to get a few more horsies out of my 94 K1100RS.

the port structure and breathing on a 4 valve engine is really different to the k75  - 2 valve type motor  so some modifications will need to happen to the map , also don't forget that the usual method for injection on k bikes is all injectors squirt at the same time   so some issues to consider during the rework of the system
good luck

duck wrote:Keep us posted please.  I'd like to get a few more horsies out of my 94 K1100RS.

Having just read the wee byline on your sig over there, I think I'm gonna hide in the bushes and trip the ponies up 'coz you deserve it for such an awful pun!!!

charlie99 wrote:the port structure and breathing on a 4 valve engine is really different to the k75  - 2 valve type motor  so some modifications will need to happen to the map , also don't forget that the usual method for injection on k bikes is all injectors squirt at the same time   so some issues to consider during the rework of the system
good luck

Definitely will be modifying the tune to compensate for the 4 valve vs the 2 valve. This just provided me some sort of footing/reference to start from rather than feeling around in the dark. I just took a look at the Microsquirt wiring diagrams, seems that there are 2 outputs for 4 injectors each, totaling a possible 8. Of course not going to need all 8. But from the drawings, I can wire the injectors all in concert to "squirt" at the same time same as the OEM configuration. So looks like it naturally can do the thing it needs to for the K1100.

Also luckily for me, the '93 K1100 includes a ignition control module that is needed for the MS upgrade with the BSK ignition coil pack that I've installed a few months back. The '94s and on don't seem to have this in the wiring diagram according the the Clymer manual. But not so lucky for me, the donor engine/fuel/ECU harness that I have on hand does not include this since it's from a '95. So I'm left with bridging off directly what I have installed, unless I find a compatible connector for the ignition control module.

Basically, the goal is to have a temporary harness to interface with the engine and get the connections/wiring correct with a running engine, then I'll make a proper harness based off the donor harness I will be working with.

Decided to do an update since its been some time since I have embarked on Microsquirting/rewiring of my K bike build. All has been ticking along as planned. I have installed the Microsquirt and created a bracket for the m unit blue:




Since I'm a paranoid fellow, I installed a backup keyed ignition lock that overrides the keyless go function of the m unit just in case
[url=https://servimg.com/view/20146454/2][/url]


I know it looks like a mess but I am sorting out all the connections before the final wiring. One thing that is tripping me up is the hall sensor. I'm am currently researching how the Microsquirt system interfaces with the hall effect output. the MS V3 version seems to handle the output better with the latest version. I might need to install an additional signal boost component that boosts the square wave of the hall sensor for the microsquirt. But this is to be determined.

After several weeks of research, thinking, reworking wiring and fiddling with settings in TunerStudio, I'm excited to report that I have successfully started up/had idling my microsquirt'd + motogadget'd K project. It's definitely not perfect. But its a big step forward (finally). Now its time for refinements and tuning the map.

mjones866 wrote: But its a big step forward (finally).

Hafta agree with that statement

And we finally have a decent microsquirt’d startup. This was a cold startup. Literally popped into the shop to test. 

Nice job! 

Love it, well done!  We'll all need to know what you had to do to get there  

@Woodie – OK, you asked for it. LOL!

I was going to start with the other modifications I've done but I'll keep with the topic specifically related to the Microsquirt install.

So here is a story/overview and list of modifications  on how I got to this point Microsquirt-ing + M Unit Blue-ing my 93 K1100LT. Even though this is lengthy, I have glazed/skipped over some of the details. There would be a lot to cover and type. I’m happy to dive into details on a particular area if anyone wants. Also, this isn’t a detailed “how to” nor am I a professional mechanic. This is more of a general summary of several months wrenching and researching prior work of other fellow Brickers.  I hope someone finds useful.

A few months back, before the initial overhaul of the wiring, I installed a 4 tiered ignition coil pack with bracket and spark plug leads from BSK Speed Works (http://www.bskspeedworks.co.uk/k-ignition-coil-ht-leads.html). From my research, this type of coil pack is used in vehicles like a Ford Fiesta. The guys from BSK are very responsive especially when it came to explaining to me the pin out on the coil pack to replace the BMW dual coil setup. In my set up, I did choose to tap the lower mounting tubes (for lack of a better description) on the intermediate housing where the original coils were located in order to get the BSK bracket on the bike. 



Now on to the actual Microsquirting, I started by labeling all the relays in the mysterious relay box. I used a few resources around on various forums that were super useful. Thus began the gutting and unplugging of the mass tangle of wiring of both the main and ignition harness.



I got rid of all the relays and the original fuse block except for the relays for the fuel pump, fan and starter. The Microsquirt cannot directly handle turning on and off those components. I made sure to leave enough wire length when I clipped them from the harness. Note: in TurnerStudio, you have to manually configure an output to run the fan to be triggered by your defined values. You can choose from a few output wires to use such as “FIDLE”, “WLED” or “ALED”. I chose WLED since I may install an idle air control valve later on. 

Another component that I could not part with is the BMW original starter relay rated at 70 amps. The M Unit Blue does have outputs for a starter relay built in, but it’s only rated for 30 amps. I played it safe and kept the original relay. 

The M Unit replaces all the fuses in the bike. It digitally monitors any faults that might occur and resets automatically with a power cycle, which is really cool. Of course, hopefully you have corrected the problem by then. I believe that it also alerts you audibly via the app as well if you have earphones in your helmet. In the manual for installing the M Unit, it calls for a 40 amp fuse that is to be wired in between the M Unit and the battery. I found a resettable breaker/fuse on Amazon that fit the bill. The M Unit does not come with a 40 amp fuse. 

Final list of components in the electrics box:

1. BMW original fan relay
   
2. BMW original fuel pump relay
   
3. Microsquirt V3
   
4. M Unit Blue
   
5. BMW original starter relay
   
6. 40 amp breaker/fuse for M Unit
   
7. Just mentioning: Roll up unused and untrimmed wires from the Microsquirt such as the MAF wire (this is just for the time being, making sure I don’t need anything in the future.) 
   

Now that I had the components placed where I wanted, it was time to start to interface the various sensors with the Microsquirt according to the documentation.

I kept the following BMW original components:

1. Hall effect sensor – this was fun (sarcasm) to figure out. 
   
2. Both BMW original coolant temperature sensors – I’m currently using the coolant sensor thats located at the top of the timing cover. The one thats a b*&!@ to get at. Not sure what I’ll do with the temperature sensor at the water pump. Thinking about replacing it with a NTC thermistor that variably increases fan speed in relation to the rising coolant temperature. Turning this on only on those 95+ Georgia summer days. 
   
3. Manifold air temperature sensor
   
4. Ignition control unit (also seen it called an “ignitor unit”)
   
5. TPS sensor (K1100s have a potentiometer not a switch type like the older K100s)
   

Components that were installed:

1. 3 bar MAP sensor (GM type DIYautotune.com recommended)
   
2. 7 port vacuum manifold (this is connected to the 4 individual vacuum ports on the throttle bodies. One connection goes to the MAP sensor, 4 for the throttle bodies. Future plan is to upgrade to a fuel pressure regulator that adjusts with vacuum line from the manifold)
   
3. LC2 wide band O2 sensor and controller
   
4. installed 4-hole Osidetiger fuel injectors 
   

All initially went well wiring each sensor to the Microsquirt (as prescribed by the documentation, theres A LOT) except for 2 things. The hall effect sensor and the MAP sensor. I initially bought a compact 3 bar from ebay. Either it was DOA or I fried the sensor somehow. I could not get it to react to a vacuum or show a correct vacuum signal for the life of me. I swallowed my pride (and not wanting to spend the money) and purchased the DIYautotune.com’s recommended GM 3 bar MAP. After it was delivered, I had it up and running within 5 minutes. Super easy. TunerStudio conveniently has setting preprogrammed for the GM 3 bar sensor instead of a manual calibration. So this was an easy fix, but had to spend double to get there. Should have gone with the recommended part. Another lesson learned. 

AND FOR THE HALL SENSOR……

At this point I had the bike cranking, controlled by the M Unit and I had spark at the spark plugs (I kept the injectors and fuel pump disconnected for testing). I read that the V3 version of the Microsquirt had a built in pullup voltage on the VRIN- input wires. So no extra modifications were necessary. IT DOES! I was able to provide the hall effect with 12v from the AUX switched output from the M Unit, ground the sensor (and ground the shield wire with it) and connect the VRIN1-. Initially I connected both VRIN1- and VRIN2- to each the orange and brown signal wires of the sensor. I tested the cranking and I had a tach signal. It was consistent at around 120 RPM. So progress was had!



To make sure that my timing was correct, I bought a 12mm with extension TDC gauge from ebay for around 50 USD. I followed the Clymer manual’s procedure for setting the timing at 6 degrees BTDC.  I also DIY'd a hall effect tester with an LED and a 1K resistor. It worked a treat. What’s funny is that I’m fairly certain the final angle I rotated the HES to was the original rotation when I first opened up the HES cover. So that makes me feel good that I got it close to factory I suppose. I can’t remember if it was the Clymer Manual or some another, but I remember reading a mistake was made in one of the manuals in regards to direction of engine rotation. The proper rotation is CLOCKWISE when you are facing the timing cover from the front of the bike. 

I decided it was time for a startup test since all looked good. After a couple of weeks of fiddling with settings and options, doing more research, fail starts, many nights having to put down the wrench because the battery was dead from start attempts, I finally got the bike to catch and startup. I had to hold the choke wide a$$ open for it to even catch (this is a whole story in itself, I’m having to adjust the tune map fueling down from really super rich). When I got to to idle, TunerStudio was showing me roughly half the RPM (roughly between 400 and 500) of what I know I should be seeing at idle. I confirmed this with a RPM sensor attached to the high tension lead and it showed ~900. I could also tell that something was off and the idle sound didn’t match up with the RPM reading. Without a proper higher RPM, TunerStudio wouldn’t get out of “cranking” mode (there are indicators in the interface to let you know when you are cranking, going through “WUE” – Warm Up Enrichment and “ASE” – After Start Enrichment) nor would the VE or Ignition tables in TunerStudio come into play since they started at 700 RPM based on the default map I was starting from. 

At this point, it was back to more research... and a beer or three. 

I continued to wrestle with TunerStudio settings, eventually got my configuration so far off that the bike wouldn’t even startup any more. But luckily I was able to restore where I was at. All wasn’t lost. 

On a whim I decided to test to see if both hall effect sensors were sending signals. They both tested good (used the aformentioned DIY’d LED tester). I then focused on the VRIN1- and VRIN2- connections. I disconnected each VRIN wire one at a time from the HES and turned the engine over. Only the VRIN1- wire was seeing a signal from one HES. I confirmed this in TunerStudio and was seeing the same half RPM before with only the one HES. Since the BMW HES has 2 individual sensors 180 degrees opposed, this lead me to thinking that I could connect 2 HES signal wires to the VRIN1- wire, in theory doubling the RPM. I connected both sensors to VRIN1- and cranked the engine...

HOLY S%*&, I HAD A FULL RPM READING. 

VE table, ignition table, AFR table, etc were all being used. WUE and ASE indicators were lighting up. 

At this point in time, I’m not entirely sure that this is a correct setup and I’m looking into making sure that there’s not another configuration that I need to explore before calling this good and permanent. There are two other trigger inputs on the Microsquirt (optoin+ and  optoin-). From what I understand, you can only use either VRIN+/- or OPTOIN+/- since they both connect to the same processor. 

This brings us to the present. As mentioned earlier, I am fighting with turning down the fueling due to the mixture being so rich. I’m getting there slowly but surely. And oh, I’ve started to clean up the wiring. I’ll finish the clean up in the next few days and get back to tuning the fuel mixture. 

Hey brother thanks for taking the time to document this - fascinating!  I was very heartened to hear that beers are part of the development process.  It gives one (me!) hope.  So once the mechanics of all the components are worked out you develop your own tuning map?  Does TunerStudio provide feedback/guidance for this?  I am intrigued by the possibilities that the Microsquirt offers but my knowledge, understanding and experience are probably more in line with a 1970's Briggs & Stratton lawn mower motor than what you have taken on.

Cheers, Woodie

mjones866 wrote:I can’t remember if it was the Clymer Manual or some another, but I remember reading a mistake was made in one of the manuals in regards to direction of engine rotation. The proper rotation is CLOCKWISE when you are facing the timing cover from the front of the bike. 

Maybe it was from the 05/99 BMW K1100 LT/RS Repair Manual that provides this line in its Technical Specifications section for the engine.

@Woodie – Beers are a must when in the shop wrenching! Makes you brave enough to wire 2 hall effect sensors together on one input to a opensource EFI controller HAHA, You can literally download the code from github.

And yes, you're on the money. And oh, figuring out the whole alternator exciter situation. AKA the BMW alternator lunchbox charging light. I will begin to tune the map tables now that all my base constant values are set, such as injector flow rating, squirts per cycle, etc. There are a few main tables that I'll spend most of my time adjusting: VE (Volumetric Efficiency, aka fueling), Ignition Advance (spark advance) and AFR (air fuel ratio).

TunerStudio itself doesn't quite guide you along as much as I would like especially since I'm a new comer (noob to the world of DIY EFI). There are short tool tips beside the options to explain what it is and sometimes what a typical value or default value should be. But from what I've read, you have to take these with a grain of salt. There are guides on how to react to particular situations. For instance, I had to set the cranking pulse curve (the percentage of fuel injected when you press the starter) up above 400% at some of the temperature ranges when it dropped below 40F a few days here in Georgia, no we did not declare a state of emergency, LOL. I used a guide from diyautotune.com that let me know to do that if cranking was an issue. There are also a multitude of support forums that help out as well.

BUT the biggest caveat it seem is that "you tune to what the engine wants". That is to say my brick currently has 110K miles on her and given the wear, and other internal nuances that it might have compared to say a brick with 30K, the tune could possibly be different.

Oh, and youtube has been invaluable for information about how to tune with TunerStudio.

There are repositories of base tune files for particular car engines that you can download like for Miatas for instance. There is a cult following around this car and Megasquirting/Microsquirting them. But these maps are base value and are general enough to get an engine started. Apparently each engine is unique in what it wants the tables value to be at.

Unfortunately for me (and us), there are no base maps for a K1100. The only known tune file to my knowledge that I was able to stumble on was from wmax351 from the motobrick.com forum. This thread: http://www.motobrick.com/index.php?topic=936.0 is what got my brain started on my Microsquirt project. It died on the vine about 3 years ago. But my tune is now completely different from what he set up since he installed his Microsquirt on his K75 and I'm running full ignition and fuel control.

I think I might post mine on here in the end for whoever else is loco enough to defy ze German engineering.

So cool, this project is not for the faint of heart!  It is too bad the build you linked to on Motobrick never came to be. It would have been very similar to what I have toyed with doing.  Your taking the time to document the process and issues that you run into and solve along the way is worth its weight in gold for anyone attempting to do this.  Is the first road test a long way out or have you done this already?

Woodie (cheering you on from frosty Canada)

Yea, this type of mod does definitely takes time and research on multiple levels. But definitely doable. I do hope someone will be able to use what I’ve done and apply it to their own application. 

However, I’ve hit a bump currently. I began the job of cleaning up the wiring and got too excited when the LiFePO4 battery I ordered arrived. Unknowing to me, these batteries are only kept at a low storage volt levels when sitting on the shelf. I hooked it up and cranked the K bike. It actually did run and I cut it off. When I went back to trying to tune, I only got a click out of the starter relay and not starter motor turn. 

I did some thorough trouble shooting. Removed the starter, bench tested it. It spun. Made sure all my grounds were solid. Did a fresh sanding of all metal contacts. Spent about 8 hours disassembling, sanding, reassembling, checking grounds. I got it to crank but only for a time or two until the relay just gave me the loud click I hear prior to my 8 hour gauntlet of ground checking and disassembly. 

I can confirm my original lead battery is testing good. And is only a year old. I know batteries can do some weirdness. I charged up the lithium bat and hooked it up to the K and same result. The same loud click. 

So now the conclusion that I can come to is that my starter relay is faulty. I’ve heard of these relays fusing closed due to a low voltage battery start attempt. Producing the “stuck cranking” effect. But I suppose the relay can fuse open as well. Either way I feel better that a newly refreshed relay is will be installed. I assume the relay was original equipped from 93. 

This is was a long post to say “no”. I have not road tested anything yet sadly. I should receive the new starter relay within a week. I’ll continue to finalize the wiring while I’m waiting.

There is a recent similar thread in the electrical section "starter issues-k100rs" that might help.  Good luck with it.

Fantastic piece of research and documentation, thanks. Beyond my wildest dreams and skillset (but that’s what I thought a year ago when Dai told me he made his own brake lines, and mine haven’t killed me yet so who knows).
Keep cracking away and savour your first ride 

Well, new starter relay arrived. Installed and tried to crank. No joy. I heard the click of the starter relay but the starter motor did not turn. So did a test and I was getting power to the starter motor, but no spin. So might have found the culprit!

Another item that arrived along with the starter relay was a starter motor rebuild kit from Euro Motoelectrics. Took about an hour to disassemble and clean the guts of the motor.



Lots of crud and dust. The brushes were almost gone. Installed all new gaskets, bearing, bushing, brushes/holding plate, and oil seal.

I think someone was inside the motor before. There was only one seal in one of the end caps.

I greased it up and put it back in the bike and VOILA! She cranks once again. Now back to tuning Microsquirt... FINALLY.

I really did enjoy the reading. It gave me hope that one day I will be putting micro squirt on my bike. Thanks for sharing and please do keep up posting new experience you get along the way. Cheers!

My apologies I've not posted about the project in a while. It's still moving forward, but had a standstill for a few months. This might be a long winded post on the project.

Nothing like a pandemic to get you back to wrenching. 

After rebuilding the starter, things looked back on track. The K bike was cranking, one evening as I was troubleshooting the starter kickback problem. She just.... stopped. She would crank, all sensors were giving readings. But nothing. In TunerStudio, you can turn on test mode and manually fire the injectors, fan output, fuel pump output and coils individually. All tests were good except no sparking from the coils. 

So I've spent the last few months troubleshooting and scratching my head. In the end, I traced it back to a combination of 2 issues. The ignition amplifier (or ignition control unit, I've heard various terminology) was toast and the IGN1 logic signal pin from the Microsquirt was showing no continuity when IGN2 was. IGN1 is the main leading spark trigger when the engine begins to crank and the Microsquirt is getting RPM reading from the hall effect sensors. All I can think that was the cause of this was user error in the settings in TunerStudio. One setting in particular that is VERY important is the Spark Output option in ignition settings. This needed to be set as "Going High". Where as "Going low" would eventually make the coil pack and igniter get really really hot. So hot it would burn you. I definitely screwed with this setting when the bike died, not realizing what I had done.

OK so,
issue 1: igniter was dead. 
issue 2: No continuity on IGN1 pin at the Microsquirt.

So I had to crack open the Microsquirt case and trace out where the path to ground was broken. On visual inspection I didn't see any burn marks or indication of fried electronics on the printed board, but this thing is so extremely tiny in the circuity, to be honest it could have fried anywhere along and I wouldn't have noticed. I checked for continuity all the way up to a resistor in the board, and wouldn't you know it, on the side that continues into the Microsquirt I got the continuity "beep" but from the resistor out to the pin which eventually leads to the igniter, I got nothing. 

So at this point, one would assume that this TINY ASS resistor was fried. I surgically jumpered around it with a 100ohm resistor and reassembled. 

In the spirit of reducing wiring, and making things as compact/efficient as possible. To replace the igniter I found one of these:



This is a Bosch wasted spark "smart" coil pack. It combines both an igniter and the coils in one package. This type of smart coil is also spec'ed out in the Microsquirt installation documents as a suitable option. The cost was pretty much the same as sourcing the original igniter. I went with the smart coil combo.

With the Microsquirt reassembled and the new smart coil pack installed, I ran through the testing using the test option in TunerStudio and all was working again!

For the time being, I DIY'ed a mounting plate for the coils:


I'm not quite satisfied with how the plate ended up, I actually just received in the mail the other day a coil pack bracket from a K1200 for a more solid mounting point. I may need to modify it just a bit, but that's a project for later.


Now back to the starter kickback... timing timing timing. Also, proper injector bank wiring. These contributed to the kickback issue I was facing.

Here's how I got things worked out:

In TunerStudio, Instead of using a not yet tuned ignition timing map while you're setting things up, you can lock the timing in the software just for this purpose of testing and adjusting the timing. 

I have the hall effect sensor plate as perfectly aligned with the edges of the curves as possible. I wanted to have as clear of a window view of the notch and case marker as I could. Since it's set and that I can control the trigger angle in TunerStudio, I should never have to move the HES plate manually to adjust timing later on.



I removed the spark plugs, locked the timing in the software to 0°,  began firing the timing light while cranking. There is a feature called "Trigger Wizard" that you can adjust the trigger angle on the fly as you are cranking until it matches up with the engine's timing marks. My goal here was to get the triangle notch to align with the TDC marker on the engine case so that I could be sure at what degree TunerStudio was reading as top dead center.

The result of this was that my timing marks line up at 45° as TDC. Knowing that K1100 spec for setting timing is 6° BTDC, its simple to get the final timing adjustment degree setting. 45° TDC - 6° spec'ed BTDC = 38° BTDC final trigger angle.

OK, I got my trigger angle set. If I see that after this process that it's off when the engine is idling with a timing light, I can make fine adjustments to the final trigger angle in the software to really dial it in. But for now, a degree or so off is fine. Confident that the ignition timing was now set, It was back to getting the K started and idling.

The K would start (meh sometimes), but idled like complete garbage. There were sometimes where it wouldn't even start. But hey, NO STARTER KICK BACK!!! Well, this is where proper injector bank wiring comes into play.

There are two injector bank control wires coming from the Microsquirt (labeled as "INJ1" and "INJ2"). You can run up to 4 injectors per bank wire for an 8 cylinder engine. I do have it wired into split banks. Initially I had INJ1 connected to injector pair 1 and 4, and INJ2 connected to pair 2 and 3. My initial thinking was that I should wiring them similar to how the coils are connected to the coil pack. WRONG.

Reading through some of my past notes, I found that the proper firing order is 1-3-4-2. Reworking the wiring, the injector pairing is now:

INJ1 – Injector 1 + Injector 3
INJ2 – Injector 2 + Injector 4

After these changes the bike fired right up and idle. All be it, I needed to open the choke and make adjustments to the idle screws initially. The fuel table will need to be tuned. At this point, the project is up to date.


Now, on to the ignition timing table in TunerStudio. I've done some deep web research into unraveling the mystery of ignition timing of the BMW K1100 in order to generate a viable ignition table to start with and test.

If anyone has any comments or more insight into this area, please feel free to correct me to add to the project. Here is the table that I have come up with:


Key takeaways from my research to get to the table map above. Timing is set at 6° up until 1300 RPM after that, timing increases as RPMs rise up to 6,000 RPM where "full on advance" is set at 30° and above. The column at 8777 is what I read to be the overrun safety in order to protect the engine from damage. Timing is set back to 6° at 8777 RPM.

With the important points established in the table map (6° at idle up to 1300 RPM, 30° full advance at 6,000 RPM, timing reset to 6° at 8777), there is an interpolate feature that will automagically generate the values between the columns. That is how I came to the values between columns 1300 RPM and 6,000 RPM.

I will note that this is most definitely an UNTESTED and UNOFFICIAL ignition table.

I'm aware to have any verification about power and efficiency the bike will need to be dyno'ed. One day I will do that. But for right now, I am going by feel to see what the engine wants.

Again, I'm open to anyone who has knowledge on this subject. I will post further on the results of the initial ignition table and once the fuel table are dialed in.

I'm feeling I might actually get her on the road in the coming weeks!!!

That's some very good reading with my first hot cuppa of the day.  

Great read indeed!  

"automagically" is what I would be relying on throughout this endeavour should I ever take it on.    Do you have a part number for the Bosch smart coil pack?  Your documentation of all this will be the bench mark for anyone taking on this kind of project.

The part number for the Bosch smart coil is 0986221048. From my research it was used in some VW models.

The BMW OEM leads do fit on the coil. But mine need to be refresh. I've got some that were delivered the other day from EME.
https://www.euromotoelectrics.com/Ignition-Wire-Set-BMW-K1100-K1-BMW-WSK1100-p/bmw-wsk1100.htm

I was doing some fuel tuning the other night and have come across a curious issue with it not wanting to rev past 2500 to 3000 RPMs.

This could be a combination of untuned/uneven fuel map, dwell settings, noise from the HES sensor, or some other gremlin that I'll need to chase down.

But she starts right up and idles strong. I'll update when I find a solution.

Time for a quick update. 

Did some wrenching in the garage today. Well more so electrical work. I sorted some grounding issues, or what could be future grounding issues specifically with the O2 sensor controller and the ground shielding wires coming from the Hall effect sensors and the shielding wire on the VR1 input coming from the micro squirt. This actually solved my TPS “pulsing” when I wasn’t touching it. As to say the values I was seeing in tunerstudio were constantly changing by +/- .5 ish volts constantly. Now after sorting the grounds, I have a nice solid and stable TPS value. 

I ensured all the ground connections went to frame/engine ground and not the sensor ground the microsquirt provides for various sensors. 

BUT, the most exciting piece today is that SHE FINALLY REVS ABOVE 2700 RPM. I still need to road test. But it looks like I’m able to hit the whole rpm range. 

In short, I connected a 1M (yes a 1,000,000 value) resistor to VR1+ Between both HES signal outputs connected to the microsquirt VR1+ input. Here’s a short ACII diagram:

HES1—
          |—[1M resistor]—VR1+— Microsquirt
HES2—

The explanation (non electrical engineer / mansplation): with connecting both HES signal outputs to the VR1+ input to the microsquirt, the signal voltage was too much or not in the range that the microsquirt was expecting.

Obviously I’ll take a deeper dive into this or come up with a dual resistor input circuit for the Hall effect sensors. 

I’m wondering if the stock HES would function with 5v instead of the spec’d 12v to be able to bring down the 1M value resistor. But that’s a future sidebar. I’ll continue with the 1M resistor at the moment. 

BUT SHE REVS!!!

sounds about right , likely expecting 5 volts ....a voltage divider might be the good way to go

keep at it , watching with interest

Im looking at running a raspberry pi with a-d converters to gather information on the venerable k100 system before moving to microsquirt , interested in injector durations etc , will need to install a k1100 throttle bodies for the tps sweep to gain that relationship also with the afm opening formulas

@charlie99 — AAAAAAAH YES! A voltage divider could work a treat. I’ll explore that avenue. Thanks for the direction. 

I would be interested in what values you gather from the injector durations, coil dwell, etcl. I’ve been kind of flying by the seat of my pants on that front. I’ve kept the engine rich in its operations at this point but definitely would like to dial it in. 

Yea, K1100 throttle bodies would provide the TPS sweep as it’s a variable potentiometer rather than a switch type in the k100. 

But would love any information you gather to put towards my project.

Did a test ride around the neighborhood this evening. 

Just realized that I put the K up on it’s center stand last June to start cutting on her. And there she stayed until tonight. So kind of a mile marker. 

But back to the ride. She rolled. Nothing too exciting other than I remembered how to ride. And fuel definitely needs to be tuned. But I was happy to be back riding. Smiles were abound.

mjones866 wrote:@charlie99 — AAAAAAAH YES! A voltage divider could work a treat. I’ll explore that avenue. Thanks for the direction. 

I would be interested in what values you gather from the injector durations, coil dwell, etcl. I’ve been kind of flying by the seat of my pants on that front. I’ve kept the engine rich in its operations at this point but definitely would like to dial it in. 

Yea, K1100 throttle bodies would provide the TPS sweep as it’s a variable potentiometer rather than a switch type in the k100. 

But would love any information you gather to put towards my project.

will do ... but I predict the injector timings - opening will be really short durations , as the squirt ex factory are timed for all 4 cylinders at every tdc ... rather than banked timings .... but your information about the timings for the relative cylinders is a good wake up to what really happens regarding advanced hall sensor timings ...may have to install a real time multi fingered type timing wheel on the front of the crank to really see whats going on ... ala Ben kinghams racing beast eh ?

OK. Been doing some tuning testing and ignition timing today. 

The 1M ohm resistor isn’t doing the job trying to touch the entire rpm range. Ran into another rev limit at about 4500 to 5000. I noticed it when trying a real road test the other evening and today checking the timing and making adjustments.  I’ll be configuring the voltage splitter suggested by @charlie99.

This should hopefully let me really push her to the full potential. 

I have a Nano Pi k2 (a raspberry pi like single board computer) that can run Linux and also TunerStudio. My aim will be to run the auto tune feature and really start to dial in the fuel map as I’m in situ riding the K. I’ll be able to stop and make adjustments with the nano pi on board. Not to mention being able to see all the gauges I have configured.

More to come. She’s running smooth and drivable at low RPMs at this point.

Installed the voltage divider last night and IT WORKED. 

Took the K for a quick zip up the road a bit and didn’t run into the “false rev limiter”. I got her up to 6500RPM To 7K ish. Here is the wiring diagram I referenced:



“Vin” is the signal coming from the Hall effect sensors. After some experimenting with resistor values, I landed on for “R1” a 10k resistor and “R2” I used a 5.1K resistor. 

Now the ground connection had me scratching my head. I initially was connecting to the frame ground under the tank. This actually produced no RPM signal while cranking. I then realized the VR1- going to the microsquirt is the ground path for the VR circuit. Connecting the 5.1k resistor side to VR1- made all the difference. The microsquirt documentation says to leave VR1- “floating” for hall sensor installs. 

So far so good and looks promising. Need to really open her up and test this weekend.

I’ll report back on the results.

great to hear the voltage divider works well

no image of the wiring map appearing for me ,,?

that auto tune feature sounds encouraging ...

ride well

@charlie99 – I fixed the broken image of the voltage divider diagram. Sorry about that.

The voltage divider circuit is completely functional. The K bike is able to fully reach it's entire rev range without a hiccup or stumble.

Before I really opened her up, I needed to tweak a change on how I configured the "squirts per cycle". Initially I had it configured as 2 squirts simultaneous. All 4 injectors were putting in fuel on each engine revolution signal from the hall effect sensors. So 2 injector squirts, per injector, per hall effect signal, per every 720 degrees. This setting had a less than desirable running behavior above idle rpms. It just sounded/felt a bit on the rough side and not the smooth like I knew this engine should be. Plus a friend of mine mentioned that he smelled gas as I drove away.

My thinking is that it was injecting fuel on the piston stokes that it didn't want or need, essentially just wasting fuel. This is my most educated guess here.

The injector setting that I have now is "4 squirts per cycle alternating". This provided a smooth rev all the way to red line. Since I have the injectors split to banks (1+4 & 2+3), the fueling seems to be coming in just where the engine is wanting on an alternating bank pattern per HES signal events rather than all 4 injectors at the same time on each HES signal event.

From some research on the alternating squirts setting, this helps keep a more constant and even fuel pressure in the rail, rather than large dips in pressure. So A+ all around.

On a deeper note into other software settings, from what I've initially noticed that the K engine doesn't quite favor a good bit of the more advanced features and settings in TunerStudio. Such as "AfterStart Enrichment", "Warmup Enrichment", "TPS WOT curve" and "Time-Based Accel Enrichment". In particular the "TPS WOT curve" feature. I have completely turned this off with being disappointed with how responsive the throttle was. As soon as I tuned it off, boom, I had a nice throttle response. Essentially, you're telling the computer at what RPM the throttle is open at by percentage turned open.

Maybe these are things that I need to take a look at again once I have a solid base tune established.

More to come on this adventure. But I believe I have a fully functional Microsquirt'd K bike.

Awesome project and thread! Ping to read later.

Not sure what your status on this project is right now, but if you need help with anything feel free to ask, I am also working on a similar project but with an ms3pro and I have my setup working very well right now, just need to get the whole bike into a ridable state so I can tune the whole ve table. And If you want to probe my brain about tuning I might be able to help there too. I also have some other things you might be interested in like a simple circut that will let you read gear position and maintain neutral detection for starting and such... If I recall correctly, the microsquirt does not have a dedicated input for gear... So you would have to set up a custom channel for that in ts.. but I think it can be done.

In any event good work, it's looking good!

Wiz

@Wiz – Thanks for shaking me down. I’ve been meaning to post an update. Even though I’m able to work from home during the pandemic, I have had little wrenching time in the shop. On top of that, my family and I just moved so I am still getting my new shop space setup at the moment. 

I would actually be interested in looking at your tune settings, @Wiz. Specifically the ignition settings, I want to compare notes to see if i’m on the right path since it sounds like you’re dialed in. Are you using the stock hall effect sensor? And are you using TunerStudio? Any chance you would be able to do export your tune for me?

I was thinking about the gear indicator, but only for the Motoscope Pro’s neutral light. But I’m definitely interested to see if I can get the gear registering in the Microsquirt! At the very least, your simple circuit would help me get the neutral light working.

Thanks for offering your wisdom! 

Here’s where I’m at … I’m dead in the water at the current moment. LOL!!! I’m dealing with the dreaded stuck/jammed, possibly broke sprag clutch issue. But no worries, I have a new (well new to me) sprag assembly and parts to do the work. Just need to find the time to literally take apart the entire bike. I’m sure the starter kickback I had in the beginning contributed to its ultimate demise. 

But I digress. Here’s my journey to receiving the well known sprag love:

After getting the voltage divider installed and tested, I was able to take it out on the road for a short test as I briefly mentioned a friend smelling fuel as I rode away in my post on June 23. So it rolled…. but power was really lacking especially starting off. I think there are a few causes here.

I updated the fuel pressure regulator to an adjustable type with a gauge and the vacuum hose connected to the throttle bodies. This is recommended in the Microsquirt install manual, but probably assuming you’re most likely installing in a car. Since a vacuum reference on the FPR isn’t OEM on the ’93 K1100, I’m going to leave it disconnected for now since It might be dumping way too much fuel into the mix at higher RPMs.

After some light research on air fuel ratio, I realized I might have made a mistake with how and what I used to connect the wideband fuel sensor to the exhaust. Here is how it’s bolted up with a couple of adapters in between: 

EXHAUST BUNG –––> 90DEG ELBOW –––> MINI CATALYTIC CONVERTER –––> LC–2 SENSOR

I have no idea why I thought that this was a good idea. I initially wanted to redirect the cable so that it pointed parallel to the exhaust opposed to perpendicular. Thought this would be cleaner. But for starters, this takes the sensor away from the heat produced by the exhaust pipe and it takes it away from being directly exposed to the vapors in the exhaust pipe. I read that these types of adaptors for fuel sensors are bad and don’t give accurate readings. Sure, I’ll bite. I have these currently removed. 

In my tinkering type way, I purchased a 3D printer. So I had to learn an entirely new hobby and the technicals around printing plastics. So this got my brain really thinking about the electronic brackets and prototyping body parts. I reworked the wiring and electric devices not being happy with the organization and mounting situations that I originally made. I’ve been printing and designing brackets for the various devices to fit inside the OEM electrics box. I’m actually super happy with how it all turned out so far. I’ve been able to cram the Microsquirt, M-Unit Blue, starter, fan, fuel pump relays, MAP sensor and the O2 sensor controller into the box. Ideally I would love to get an antigravity battery in the electronics box but I’m afraid that space is not going to allow me the luxury that I can see. Maybe I’ll print up and new box in the future I’m sure I’ll go through some other iterations of the wiring box.

In my tinkering type way … again … I’ve installed throttle bodies from a K1200 that has a stepper motor type of idle air controller. The IAC will be a future update. The Microsquirt can’t directly control the IAC, it needs a separate stepper adapter which efisource.com sells at a decent price. Having the throttle bodies from a K1200 presents an issue of no longer having access to the stock K1100 “choke” connection. I think I can come up with another solution until I get the stepper motor ready. I also had to rework the throttle cable connection to the throttle bodies since it connects differently. I was able to cut the covering sheath and expose more cable. It’s action is smooth and looks to be working. Another situation that arose was that if I have the stepper motor installed on the K1200 bodies, the stock K1100 fuel line routing is really tough. The stepper motor is in the way of the return fuel line. I found an anodized red fuel rail from a K1200 GT (I think) that has banjo bolts at either end. I have seen this fuel rail used on some of the old turbo applications on the K series. This will give me plenty of options for routing fuel lines when working on the stepper motor. 

And back to the sprag. In testing the K1200 throttle bodies and the reworked wiring, she eventually gave up when trying to turn over. I thought it was the starter motor since it was essentially the original but only having refreshed the brushes. Bought a new motor just for good measure. Having the new starter motor installed, she only free spins and doesn’t want to grab.  

But this is where I’m at. I can take photos of the various projects and share the 3D print files (currently using Blender for 3D designs but looking at learning Fusion360) if anyone is interested. But the immediate task at hand is getting at the sprag for replacement. 

TBD. My K bike project is far from over.

I can send you my current tune if you want, just know it is only partially tuned at this point, I am still waiting on a new muffler so I can ride it around the neighborhood without annoying the other people. I notice you are trying to imitate the stock timing table, it would seem, I suppose if safe is what you want to be then this is fine, but there is performance on the table as well as stability in idle to be had with a more modern approach to the timing, since we have a modern ecu, timing can be whatever we want wherever, unlike the old days where it was all analog. But in any event at the very least I would recommend you put a bit of a V shape around the idle rpm, such that the rpm you want to idle at is roughly at the bottom of the V. This helps stabilize idle because as rpm falls, timing increases, making more power and pushing the rpm back up. I will edit this post and throw my timing table in the bottom.

Here is my afr target table and my timing table that I am currently using. And no, I am using a magneti marelli sen8d with a toothed wheel (purchased from bsk speedworks) Details on my project are available here on mu thread if you want to see what I have been up to: https://www.k100-forum.com/t17053-k100-ms3-pro-conversion



Oh, and as a side note, you should try mounting your wideband sensor with an angled bung like my setup if you need room, just make sure the element has a clear shot to the inside of the exhaust pipe and you should be good, Here is mine, pardon the awful weld it was my first time with TIG.


Lastly Here is a link to my current tune files, VE table with be very different mind you, since im on an 8 valve and I have 205cc/min injectors. https://drive.google.com/drive/folders/1IMYpwHIgfjPd1ecGGAEXa-HBSmDQcAMZ?usp=sharing
Wiz

Quick update on my K-Microsquirt'd project.

I have completed disassembly and reassembly of the K to replace the sprag as well as tested it's functionality turning the engine. The teeth in the old part are definitely worn and very visible signs of pits. I think I will look into rebuilding it when/if it goes out again in the future I will have a fresh part on the shelf ready to go. 

I did some initial start up testing to see if I could get her to catch and idle. After some tweaking, she started and idled, all be it between 500-600-ish rpm. I call this a success for sure. 

Now it is time to head into tuning the systems.

@Wiz, thank you for all your information and data! I'll be referencing your project posts and the other documentation, obviously making the necessary adjustments given the differences. 


Stay tuned!

Glad to hear you are finally getting some progress underway again, I just took delivery of some long awaited parts for my project, and will be getting back to work soon. I hope to get my new front end dialed in, new rear shock in, rear lighting, and then have a ridable bike! Wont be completely done of course but most of the way there.

Wiz

I have been looking at this most and an earlier one for a K75.   I have taken several of the parts like the timing wheel from the K75 thread and created it.  I have used most of the same items you have on this project, and worked closely with the recommendation from the Microsquirt manual.

Thanks for uploading your Microquirt project, I noticed you listed a fuel pressure sensor "2", can you tell me which one you are using and it you added a bong to the end of the fuel rail to install it?   Also have you changed your fuel regulator?

Thanks everyone for the great information so far and the new knowledge you will post.

Todd