What K is your Scorpion based on?  I'm guessing K1100 from what looks to be a 50A alternator.

That two pin plug in pic 2 for a Powerlet socket for powering aux gear. (Like a cigarette lighter plug.) It can also be used to hook up a battery tender.

Those four terminal connectors look custom since in the factory wiring the colors usually match from one connector to its mate.

The one with the three yellow wires and a brown is the from the GPI (gear position indicator) switch on the transmission which tells the instrument cluster what gear the transmission is in.

http://www.kbikeparts.com/classickbikes.com/ckb.tech/0.ckb.tech.files/gpi/gpi.htm

You should also post up a pic of the whole Scorpion.

Many thanks for chipping in

It's a K1100 but I don't know what year and it seems there are quite a lot of differences!

So I can ignore the 2 pin plug for now, that's good to know

The GPI is one of the bits that works so I'll leave that alone!

Pic of the car is below:


I was swaying towards ECU failure so I just pulled it off the car and it rattled!! I opened it up and found a cap flapping around so I've just ordered another one, I know it won't be as simple as just that but I'll start there.

Is there any kind of resource that shows the Motronic pin outs? I want to check the clutch/neutral start/kill switch is all in the right state

Thanks for the pic. Always wanted to see one in person.

Clutch, neutral, start/kill is handled by the instrument cluster and right combo switch, not the Motronic.  If it's in neutral or the clutch is pulled in then the starter motor should spin up even without the Motronic connected.  But of course the Motronic is needed for it to fuel and fire.

Early K1100s have a different Motronic than later ones.

Early:



Late:



Which is yours?

Neither



Great thanks, so the fact I've got no voltage at the injectors is not likely to be any of that then?

As for the car, it's chassis #3 so quite special if I can make it go (which is hasn't for a long time!)

The body tells us that it's an early one.

Some K1100s came with catalytic converters, some didn't.

All of the US ones are cat'd but I think yours might be a non-cat one.

THIS site says that Bosch number is from a K1. Of course there is overlap in ECU on different BMW motorbikes. Is there a BMW number on it starting with 1 464 7XX, the 'XX' representing the remaining two digits?

Further research shows it to be a BMW part number 13 61 1 464 417, which supersedes to a number of other part numbers, all interchangeable.

13 61 1 464 479 the most recent part number

13 61 1 464 710
 
13 61 1 464 196, 288 & 289

Fits K1100 and K100-16V, prior to 7/93, when BMW eliminated the separate ignition amplifier. I have two extras in my spares supply, both function.

HERE'S a great link for deciphering Bosch/BMW ECU part numbers. Just add the main group number of 13, the subgroup number of 61 and then what BMW calls the 'seven digit unique identifier' X XXX XXX.

Thanks, the engine was originally a K100 8 valve apparently. 

There is no BMW number on it sadly. Do you know if the K100 ECU could drive a K1100? I have no idea what they changed between them

It would be great to know what other ECU options I have as this has been chipped and is now damaged so is suspect!

I'd love to get a schematic of the ECU if anyone knows of one

jseaman wrote:Thanks, the engine was originally a K100 8 valve apparently. 

There is no BMW number on it sadly. Do you know if the K100 ECU could drive a K1100? I have no idea what they changed between them

It would be great to know what other ECU options I have as this has been chipped and is now damaged so is suspect!

I'd love to get a schematic of the ECU if anyone knows of one

The ECU from a K100, because it uses a 'flapper' inside the airbox and is a totally different type of fuel injection known as LE-Jetronic, will not function in a K100-16V or a K1100. The latter are 'Motronic 2.1'.

See my list of part numbers and other details above for more info. There are several companies worldwide who will repair a damaged ECU. But I'll wager you can get a clean, used spare from eBay or a forum member locally for not much dosh.

Please post a picture of the fuel injectors and throttle bodies and we'll be able to tell if it's a 2V or 4V motor.

I don't 100% know off the top of my head if 2V motor can be run with a 4V Motoronic but it's probably possible.

I know that Grinnell chipped those bikes which you can't do to a 2V L-Jetronic so that might be why they have a 4V Motronic running a 2V motor.

duck wrote:Please post a picture of the fuel injectors and throttle bodies and we'll be able to tell if it's a 2V or 4V motor.

I don't 100% know off the top of my head if 2V motor can be run with a 4V Motoronic but it's probably possible.

I know that Grinnell chipped those bikes which you can't do to a 2V L-Jetronic so that might be why they have a 4V Motronic running a 2V motor.

In my experience, one could, with the correct engine wiring loom, run Motronic 2.1 on an 8V engine as all the critical pick up points required are the same, though you might find a temperature sensor that has a different configuration to its connector. Of course, the 8V airbox guts would be redundant, but the ignition wiring plug is the same pattern. Only K1200RS/GT differ from K100/K1100 there.

As Duck suggests, to determine whether K100 8V or a 16V motor, describe the rubber intakes just above the throttle bodies. Are they rubber accordian-shaped, or smooth rubber 'tubes'?

So I can use any of these:

13 61 1 464 479 
13 61 1 464 710
13 61 1 464 196
13 61 1 464 288
13 61 1 464 289

Is that right?

And I must have a K1100 ECU then based on the AFM (is it MAP on the K1100?)

I'll do the cap repair myself, the PCB looks fine but it's the invisible issues that concern me.

It has a Grinnall 'Superchips' install.

See attached pic of the injectors and TB inlets, they are accordion shaped

The injectors fire into the base of the TBs, not directly into the cylinder head port, so it's a K11 or K100-16V. There is no AFM on this model, only K75 & K100-8V. Yes, any of those ECU in my list, but click on the link in one of my previous posts to determine which other numbers you can use by crossing it from the Bosch number.

Thanks, sorry for my ignorance but by K11 do you include K1100? I don't know the numbering at all yet? And how would I tell if it is  a K100 16V or 'K11'?

Sorry just gone through the link, lots of options there!

jseaman wrote:Thanks, sorry for my ignorance but by K11 do you include K1100? I don't know the numbering at all yet? And how would I tell if it is  a K100 16V or 'K11'?

Sorry just gone through the link, lots of options there!

By K11 I mean K1100RS and K1100LT, but also interchangeable with K100-16V and K1 models. Stay away from K1100 from late '93 unless you wish to remove the separate ignition amplifier. Your part number suggests your trike has this, the earlier type. Without the ign amp it would then be using the later Motronic 2.1 as I have in my Big Block (shown elsewhere). This later ECU was used in catalyst/oxygen sensor equipped models.

Wow there are a lot of K numbers!! So a K11 refered to K1100xx, what is the difference between an RS and LT ECU? And the K100 and K1 are interchangeable also with the K11, why so many numbers?!

Any idea how I work out what year my current engine is? Mine does have the separate ICU, I can't find any wiring diagrams for that either!

You know where the oil level sight glass and filler cap are? Under the filler cap there is a smooth upright section facing to the right hand side with the engine and engine code numbers stamped on it. Can you get at it to read them. I have a friend has a Scorpion but his is K1100 and you can access both. You might need to use phone to take a photo but the engine code is on that

Fantastic thanks, will take a look tonight

The K1 and K100RS4V are both 1,000 CC motors that use the same Motornic. They do not use the same Motronic as the K1100s though.

K1100s are 1,100 CCs.  The difference between the RS and LT is the frame and fairing but the motors and Motronic are the same. RS is the sport version and LT is the touring version. 93- and 94+ K1100s use different Motronics.

There is a date cast into the top of the engine block above the rear of the crankshaft but you need to remove the bottom half of the air box to see it.


.

Brilliant, that's really useful, thanks

OK so I have:

114EA 0293 2259

February 93?

jseaman wrote:OK so I have:

114EA 0293 2259

February 93?

See link to help decipher the engine number:
https://www.k100-forum.com/t7276-complete-2v-engine#83840

Reading yours it says:

• 11 = 1100cc 
  
• 4 = 4 cylinder
  
• EA = emission code
  
• 02 = manufactured in the 2nd week of the year (not "Feb" as you guessed)
  
• 93 = 1993 (year of manufacture)
  
• 2259 = number of engine off the production line in that week/year
  

Great thank you for that (and indeed everyone who has been helpful on here!)

So at least I now know what I have, the only ECU I can find is this one:
https://www.ebay.co.uk/itm/BMW-K1100-LT-ECU/362261830507?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2763.l2649

And frustrated to miss this bargain the other day!

https://www.ebay.co.uk/itm/-/273292038674?nordt=true&orig_cvip=true&rt=nc&_trksid=p2047675.l10137

I'm still no closer to a pin out for the ECU or ICU sadly which is what I really need but will see how the ECU behaves with this new cap on later in the week

That's a 93 Motronic pinout I did some years ago.  Not 100% sure it's correct and it's probably for a cat'd US bike and I suspect yours may be non-cat.

Thanks, from what I can tell, pin 1 is +12V and pin 2 is ground which doesn't tie up


Mine doesn't have a cat now but no idea from the factory!

I've never struggled to find a wiring diagram for an ECU before, it makes things very tricky!

Pin 12 is output to the diagnostic plug. On a bike that diagnostic plug would be a capped off (with a blue cap) three wire connector somewhere near the left top of the battery.

Thanks, I'll see if I can find that

I finally had a bit of progress!

I've soldered the new cap onto the ECU and it did nothing as expected. I realised that I have an immobiliser in the loop which, whilst it appeared to be working (solenoid click when you put the fob on), could have been interfering. I got bold and ripped it all out only to find the two wires it interrupts were the starter signal and the 12V feed to the injectors. 

The good news is I now have volts at the fuel injectors which is great. I need to do some more work to track the starter signal wire issue (hopefully I can get that resolved pretty swiftly). I'll rip out the rest of the alarm stuff (just LED and fob bits) then start working on spark. 

Oh, and I found the diagnostic connector tucked away under a bit of the loom so that may come in handy too.

Maybe it will live again one day ...

OK back to you guys again, hopefully you can help me move forward again.

I have soldered back in the original loom and I can crank the engine on the starter now. I have +12V at the spark plugs and +12V at the fuel injectors. Neither appear to be firing though.

I've done a crude voltage measurement on the hall sensor and I can see it changing state when cranking so it doesn't appear to be dead. 

So, any ideas on where to go next. My thoughts currently are that if the hall sensors are doing their job I'm really only left with an ECU fault but all other ECU functions appear to be working.

Considering that both functions rely on an earth being exended to make the circuit then have you checked that all (and there are quite a few) the brown earth wires are connected under the screw on the main spine tube under the tank. Have a good search around and make sure one has not escaped and is hiding in the mass of wires.

Thanks, I don't have a spine tube or the tank and the earths are all black but it's a good idea to have a hunt around them so will do so asap

Starter signal issue may be affected by what was done with the side stand and clutch switch wiring off the original bike.

If you have a working neutral light you should be k, but if you don't then you will need a working clutch switch or preferably a looped out clutch switch and possibly a looped out side stand switch. These are easy to do once you find the connectors......ones off broken switches work fine.

I have spare Motronics - let me know if you want to borrow one for troubleshooting.

FYI The one on eBay you are looking at has a broken mounting tab.

Yes the neutral light works correctly. From what little schematic I have found, the stand switch hits the fuel pump relay (which is working) and the clutch switch seems to go to the 'combined right' so I guess starter/kill switch which are working. That said, I'd really love to know which pin on the Motronic it is so I can actually measure it!


I did notice the broken tab but thanks. I'd be absolutely delighted to try an alternative ECU if you are willing to help out? Really appreciate the input as usual folks, thanks

PM me you address and I will send it to you

The Motronic is not involved in getting power to the starter.

When the clutch is pulled in the clutch switch sends 12V to the start/kill switch via a black/green wire.

When the bike is in neutral the instrument cluster sends 12 to the start/kill switch via another black/green wire.

If either is sending 12V to the start/kill switch then pressing the start button sends 12V to the starter relay via a black/yellow wire.

Ah I see, thank you!

None of those wire colours tie up with what I'm seeing but the principle helps. There is a white wire with a red stripe that is the signal to the relay which, thinking about it, is straight from the ignition barrel so I guess I have bypassed both of those?

OK so I'm pretty much back to stock now I think. I fitted a new ignition module which made no difference.

I've got the hall signal right up to the ECU which changes voltage when cranking so the only thing I can think of between that pulse in and the injector/coil pulse out is the ECU itself. Whilst checking for spark I managed to get a little shock when turning the ignition off so I know everything is doing what it should except the signal to pulse the coils.

Fingers crossed Ringfad's ECU might confirm my suspicions...

Motronic tested yesterday , got distracted fixing a friends K1100RS (burst brake pipe) so missed the post.

Will try and get it posted tomorrow but at least you will have a known good one to play with.

That's amazing, thank you very much for your help! I'm hanging all my hopes on that being my fix now!

I wonder if Ginnall's replacement ECU ICs deal with the fueling mismatch between the Motronic and the K100 engine?  Mike put that setup on a rig when he was building the Braun replica and the resulting power graph was - to say the least - a bit ugly.

Don't throw the old Motronic away. You may need those ICs to get the engine to run properly. If it fires up with Simon's Motronic but runs like the proverbial bag of shit, consider that might be the problem.

Today I changed every fuse in the car just in case. I found I can't read error codes out so the ECU is definitely suspect

For the TPS, when I ground pin 3 of the diagnostics connector, pin 1 is always +12V. Measuring the TPS signal at the ECU, I had 1.7V at idle (should be max 0.4V) to 4.7 at wide open. I've now set this to 0.38V at idle but still have +12V on pin 1 when pin 3 is grounded

On the plus side I have headlights and half of one side when indicating

Dai wrote:I wonder if Ginnall's replacement ECU ICs deal with the fueling mismatch between the Motronic and the K100 engine?  Mike put that setup on a rig when he was building the Braun replica and the resulting power graph was - to say the least - a bit ugly.

Don't throw the old Motronic away. You may need those ICs to get the engine to run properly. If it fires up with Simon's Motronic but runs like the proverbial bag of shit, consider that might be the problem.

I certainly won't be throwing the old one out!

It looks like there is just one 'superchips' Grinnall chip that is fitted. What is the mismatch you refer to?

The fueling is simply wrong - it's mostly running rich IIRC.The Motronic is trying to feed a 4-valve engine whereas yours is a 2-valve engine. If you're refering to the 20-pin (?) IC in the middle of the PCB (it should be mounted in a socket), then yes, you'll need to fit this instead of the standard IC in Simon's unit.

Try Simon's unit first; if the engine runs then try swapping ICs. This will tell you if your IC is still okay. If it isn't, it's worth talking to Grinnall but they'll most likely want to charge a fortune if they still have the fueling map.

Simon - if you want to leave your Motronic with James, I have one here you can pick up next time you're passing. It's not a great deal of use to me and came with a bunch of 2-valve stuff.

Dai wrote:The fueling is simply wrong - it's mostly running rich IIRC.The Motronic is trying to feed a 4-valve engine whereas yours is a 2-valve engine.

In posts #20–#23, it seems to me the engine was identified as a K1100.

Thanks Laitch - missed that - serves me right . The comment about replacing the IC still applies though.

Yes indeed it's an 1100 and that's exactly the process I was going to follow thanks

Can't get over how helpful you guys are, thanks!!

The Motronic is on it's way, it is travelling from Dublin so may not be as quick as Royal Mail :-)

Ringfad wrote:The Motronic is on it's way, it is travelling from Dublin so may not be as quick as Royal Mail :-)

That should be there for Wednesday if it's in this evenings mail!.