Gentlemen: HELP !!!

A while ago, my K100 suddenly ran on 2 cylinders (2&3).  After some useless farting around, I did this:

1. Installed 2 brand new coils that tested ok (per Frog's prescription: ~3Ω / ~2.6kΩ)
2. Installed 2 brand new Hall sensors that tested ok (per FP: on w/o metal blade / off with blade)
3. Checked continuity of wires to ECU plug.
4. Started the beast first crank and it ran A1 (I mean, really A1 - smooth - sound - power)...for one lap around my subdivision here in Manila and then suddenly died.
5. I added some gas.
6. It ran on 2 (2&3 again but I don't think that's significant
7. I checked the coils (OK)
8. I checked the Hall sensors (OK)
9. I checked the continuities (OK)

I'm ready to torch it unless someone comes to my rescue.  Please.

Klaus

Then it's only the ignition ECU left, as all other things in the chain seems to be OK.

Thanks, Inge
Your analysis sounds alright, I guess, but how do you explain the loss of 2 cylinders (per one of the coils)?  The ECU seems to get the correct signals from the Hall sensors (they work and the lines are continuous and the male and female connectors are fine).  I guess there's that small probability that the ECU packed in just then, or at least, some of it since 2 cylinders are still firing
K

Have you checked if you have a signal from the ignition ECU to the rearmost coil?

Not yet, Inge
But will do tomorrow (it's 10pm here now)
K

If you have a signal in to the ignition ECU and not out, the answer is given.

Inge
I assume that signal out would be approximately 12V rapidly intermittent.
K

The coils have constant 12V+, the ignition ECU grounds the coil in the correct moment.

Ahh.
Would be grateful for a test procedure then.
K

Using a 12V LED across the terminals would the safest way I'll guess.
Or a high impedance analog multimeter.


Green/yellow wire is power, black/red is signal.

Hi Inge
Call me dense...which terminals?
K

Where the wires is connected at the coil.

Hi Inge
Thanks for all of your helpful comments.
I'm not sure, however, just how to test the ECU - connecting wire - coil system with the LED and so, would really appreciate a step-by-step description.
K

Connect the LED between the green/yellow and the black/red wire terminal.
Push the starter button, the LED should flash every full rotation the engine does.

Note: the LED functions only when it's correctly connected regarding the polarity.

Add some length of small gauge wire and a pair of plastic covered alligator clips,
then you have a small handy instrument to check if power is present or not....
also on sensitive electronics.

Don't know if it helps.  This is the signal going to the primary side of the coils, measured relative to ground (frame).

Great - that should do it.
I already have an LED tester I made to test the Hall sensors (Per Frog's details).
Should have results in a flash (so to speak).
k

Inge & Rob

Thanks for the electronic details - I note that the ~7ms frequency is hard to discern with the naked eye but I did see the LED flicker.

I connected the +side to the front coil (black/blue wire) and got a steady light when I grounded the LED and a flickering LED when I pushed the start button.

The same procedure on the rear coil (black/red wire) did not light the LED.

Since the coils are new (and tested OK), I conclude that the fault is in the black and red wire to the ECU.

Is that a reasonable conclusion or could it still be a partially faulty ECU?

k

Do check and clean the electrical connections at the ECU. Many times on the K the problem is a poor electrical connection and not the component. Can you swap the ECU?

Inge, Rob, and Olaf

Re ECU connections: I sprayed both sides with contact cleaner and all male and female connectors look ok

Re ECU swap: only got one at the moment

Re continuity: black/blue wire continuous to ECU terminal 14 and black/red wire continuous to terminal 9

I did another test that may provide clues as to the problem.

The LED test rig: alligator to + side of battery and other side to - lights up the LED

1. Inge B.' advice:

alligator to yellow/green wire and other end to black/red wire (rear coil)...ignition on - LED on (steady), starter - LED on (steady)

alligator to yellow/green wire and other end to black/blue wire (front coil)...ignition on - LED off, starter - LED flashing (maybe one per rev)

2. robmack's advice:

alligator to black/red wire (rear coil) and other end to ground
...ignition on - LED off, starter - LED off

alligator to black/blue wire (front coil) and other end to ground
...ignition on - LED on (steady), starter - LED on (flickering)

I am really stuck here 

any thots?

Hi Klaus (and others on this thread)
Sounds pretty frustating.
This may already be understood so forgive me if so.
You mention the ECU which is commonly used to refer to the fuel Injection control unit located under the seat just above the battery. The Ignition Control Unit (ICU) is located under the tank just behind the head stock. Hopefully you've identified the correct unit.

Hope you get it sorted
Cheers

I don't want to cut across what is a very good train of thought.

But on my LT I had a problem and checked and cleaned all the ECU contacts and it still didn't solve my problem. I know at that time it as centred around the two earth pins from the ECU. However when I swapped it out with a replacement the problem was solved. Out of morbid curiosity I swapped the 'old' one back in more recently only to find it works. I never had it tested so this was all that was done. My conclusion is there was some intermittent problem with the pins, either on the ECU where they go into the unit, either in the plug, between the pin connector and the loom.

I have not had my coils off for a while but just trying to remember is there a connection from the 1/4 coil to the 2/3 coil? If there is could there be a problem in that? You do now know both coils are good.

The puzzle for me is having one coil working and the other not working! Does the Hall sensor give a single signal to fire all 4 plugs on the wasted spark system or does it give 2 separate signals...one for each coil?.

Klaus from what you say there the Black/red has a permanent earth on it. Remove the plug from the ignition control unit under the front of the tank and test the black/red wire for earth If there is an earth with the plug removed then the fault is in the wiring loom and the B/R wire is probably chafed or similar. If the earth is not on the B/R wire then the fault is in the ICU (Ignition Control Unit) They can be repaired, I know of a place in Sydney that repairs them but whether in the Philippines I couldn't say.

Thanks for all the ideas.

Kap H: these computers are called different names by different people in different publications - YES, we're talking about the ignition module, or ICU, here.

Olaf: Intermittent problems are obviously the most difficult to solve and I may have one of those, or not.

Rick G: I will have another look at the black/red wire situation tomorrow but I'm not hopeful.  It may indeed be the ICU (see question below).

Let's see...

I have installed 2 new Hall sensors that I tested.

I have wires that are continuous from the HESs to the ICU female plug; therefor, the 5-pin connector must be OK. 

The HESs are connected to the correct pins (TDC to #5 and the bottom HES to #13)

I have installed 2 new coils that I tested

The rear coil has the sensor wire black/red and it is continuous to the female ICU plug pin #9

The front coil has the sensor wire black/blue and it is continuous to the female ICU plug pin #14

Note: the green/yellow power wire essentially connect the 2 coils as do the brown ground wires.

The female receptacles in the ICU plug are clean and look ok and the matching pins in the ICU are also clean and straight and look ok

And with all that new and tested and continuous stuff, I only get the right reaction from the front coil (per Inge B. advice); i.e., a flashing LED when the starter is engaged while the rear coil only produces a steady LED.

Here's the question (maybe the only one remaining???): could the ICU be capable of producing a correct signal to only one of the 2 coils?

Any theories will be gratefully received and tested.

I don't have the answer to the question about the ICU sending signal to only one of the two coils, but that goes back to the question if its sending signals in separate wires to the coils separately then your question is good, but also I would be suspecting the wiring down to the 2/3 coil in that case.

Its just that when I had my coils out I have a vague recollection a wire went from one coil to the other one......I think it was an earth too.

Anyone near you to swap an ICU?

RicK G wrote:Klaus from what you say there the Black/red has a permanent earth on it. Remove the plug from the ignition control unit under the front of the tank and test the black/red wire for earth If there is an earth with the plug removed then the fault is in the wiring loom and the B/R wire is probably chafed or similar. If the earth is not on the B/R wire then the fault is in the ICU (Ignition Control Unit) They can be repaired, I know of a place in Sydney that repairs them but whether in the Philippines I couldn't say.

Hi Rick
In case it comes to the repair - what's the cost?
I'd hate to install a used one and new ones are as much as a used K bike

92KK 84WW Olaf wrote:I don't have the answer to the question about the ICU sending signal to only one of the two coils, but that goes back to the question if its sending signals in separate wires to the coils separately then your question is good, but also I would be suspecting the wiring down to the 2/3 coil in that case.

Its just that when I had my coils out I have a vague recollection a wire went from one coil to the other one......I think it was an earth too.

Anyone near you to swap an ICU?

Olaf
As I noted, the green/yellow power wires essentially connect the 2 coils as do the brown ground wires.

the output switching devices could be at fault
but its worth breaking the seal on the icu and having a quick look inside

a problem exists in that the output switching devices are mounted to the housing - guts of the icu  preventing lifting of the circuit board without unsoldering them  from their lands (connection points )

if you have a little experience with soldering - desoldering  and it doesn't worry you, I recon lift the legs and have a look inside,  if nothing is black (where it shouldn't be )  a repair could be possible else get a new - replacement unit  

a good electronics person might be able to make a repair ...keep in mind that labour charges are the biggest hit to repair costs of electronics these days ....making what is perceived a high cost for such ......with cheap (secondhand perhaps ) replacements available  ..but consider the new price if none can be found and the repair could be economical . keep in mind that there is little documentation available and could be a specialist job in reality ,,,as testing of the repair will present some issues .


the output devices have come miles  and miles in capability's since production date ....and cost as well has plummeted for some thing equivalent .

good luck

Klaus,

I don't think you should even consider a new one. Certainly not at the moment. I got a used one off Motorworks and even still they are only about £50 and they guarantee used parts. Even with postage costs its a cheap deal. When mine was down it was €75 just to have it tested so I figured it was cheaper to get a used one anyway as it was less than the cost of the test.

I suspect a used one will be less than the repair cost too.

charlie99 wrote:the output switching devices could be at fault
but its worth breaking the seal on the icu and having a quick look inside

a problem exists in that the output switching devices are mounted to the housing - guts of the icu  preventing lifting of the circuit board without unsoldering them  from their lands (connection points )

if you have a little experience with soldering - desoldering  and it doesn't worry you, I recon lift the legs and have a look inside,  if nothing is black (where it shouldn't be )  a repair could be possible else get a new - replacement unit  

a good electronics person might be able to make a repair ...keep in mind that labour charges are the biggest hit to repair costs of electronics these days ....making what is perceived a high cost for such ......with cheap (secondhand perhaps ) replacements available  ..but consider the new price if none can be found and the repair could be economical . keep in mind that there is little documentation available and could be a specialist job in reality ,,,as testing of the repair will present some issues .


the output devices have come miles  and miles in capability's since production date ....and cost as well has plummeted for some thing equivalent .

good luck

Thanks for the tip, Charlie
Btw, a new ICU is only $US1304.22 at Max' and I saw a used one for $190.
If that black/red wire ground fault finding doesn't result in a fix, I will attack the ICU.

92KK 84WW Olaf wrote:Klaus,

I don't think you should even consider a new one. Certainly not at the moment. I got a used one off Motorworks and even still they are only about £50 and they guarantee used parts. Even with postage costs its a cheap deal. When mine was down it was €75 just to have it tested so I figured it was cheaper to get a used one anyway as it was less than the cost of the test.

I suspect a used one will be less than the repair cost too.

no doubt but keep in mind that I already have a used one.  Pretty well all used parts shops guarantee their bits but it's the bother (and cost) to ship the things back and forth.  Here in the Philippines, you get to pay duty on the cost of the parts, the shipping cost, and the insurance plus a few add-ons PLUS the mind-numbing experience.

Used - Ignition control unit | ELK59018 Fits K100, K100RS, K100RT, K100LT
Larger Image	Situated underneath the front of the fuel tank, just behind the headstock, this part applies to four cylinder models only. For the K75 version, please see ELK59018 .	£60.00 No VAT payable

Motorworks.!

This one is for 8 valve engines.

This is the guy in Sydney that repairs them http://www.cdirepair.com.au/  He is mainly noted because he can change or remove the rev limiter.
I would be inclined to get a used unit they are fairly trouble free, we see very little problems with them here.

charlie99 wrote:the output switching devices could be at fault
but its worth breaking the seal on the icu and having a quick look inside

a problem exists in that the output switching devices are mounted to the housing - guts of the icu  preventing lifting of the circuit board without unsoldering them  from their lands (connection points )

if you have a little experience with soldering - desoldering  and it doesn't worry you, I recon lift the legs and have a look inside,  if nothing is black (where it shouldn't be )  a repair could be possible else get a new - replacement unit  

a good electronics person might be able to make a repair ...keep in mind that labour charges are the biggest hit to repair costs of electronics these days ....making what is perceived a high cost for such ......with cheap (secondhand perhaps ) replacements available  ..but consider the new price if none can be found and the repair could be economical . keep in mind that there is little documentation available and could be a specialist job in reality ,,,as testing of the repair will present some issues .


the output devices have come miles  and miles in capability's since production date ....and cost as well has plummeted for some thing equivalent .

good luck

Based on all the checks and tests, I was pretty well convinced that a look inside the ICU may be revealing and so, I bought a cheap ($2.65) desoldering pump and attacked the thing.  Obviously, I was not the first - the seals on the screws were gone and so was one of the screws.  Once inside (after 21 unsolderings !), I noted a few anomalies:

1. cracked (what look like) little transformers repaired with some epoxy stuff - I figure that since the bike ran like that, I'd leave it alone
2. Lots of dirt or soldering paste remains on the 15 pins so I cleaned that nicely with a little SS brush before and after soldering - this may have been the cause of the grounding of the black/red wire
3. a component missing in the case - a\what would have been a 1 inch diameter thing screwed in with 2 screws - I figure that since the bike ran like that, I'd leave it alone and in any case, I don't know what's missing
4. one of the 15 pins was broken off - maybe due to my work - but I soldered it on again
5. One of the 6 central pins had been repaired so I left it like that

And then, I put it all back together and installed it and found that the tests at each coil were positive; i.e., the LED flashed as prescribed by Inge B.  

Unfortunately, the bike won't start because the fuel pump doesn't work. So, I fixed one problem and apparently, caused another.  Well, there's tomorrow.

Klausmeister wrote: Unfortunately, the bike won't start because the fuel pump doesn't work. So, I fixed one problem and apparently, caused another.  Well, there's tomorrow.

The fuel pump relay coil is grounded through the ignition ECU at pin #7.

You will get the no 7 pin sorted easily enough, its a common enough thing.

At least now you know where the problem arose.

I would over time get myself a cheap used ICU and swap it to make sure its good. Keep your current one as a spare.

Yours was worked on before and its possibly a fail again at some time. Nothing like having a spare one there if it happens. Like when my rear shock needed replacing day before going to France. Went out with a cup of tea and had it swapped with the one on the spares bike while enjoying the tea!

92KK 84WW Olaf wrote:You will get the no 7 pin sorted easily enough, its a common enough thing.

At least now you know where the problem arose.

I would over time get myself a cheap used ICU and swap it to make sure its good. Keep your current one as a spare.

Yours was worked on before and its possibly a fail again at some time. Nothing like having a spare one there if it happens. Like when my rear shock needed replacing day before going to France. Went out with a cup of tea and had it swapped with the one on the spares bike while enjoying the tea!

thanks

Inge K. wrote:

Klausmeister wrote: Unfortunately, the bike won't start because the fuel pump doesn't work. So, I fixed one problem and apparently, caused another.  Well, there's tomorrow.

The fuel pump relay coil is grounded through the ignition ECU at pin #7.

thanks

Just make sure the multi pin plug into the bottom of he fuel tank is fully home and a good electrical connection. No doubt it has been on and off a lot.

92KK 84WW Olaf wrote:Just make sure the multi pin plug into the bottom of he fuel tank is fully home and a good electrical connection. No doubt it has been on and off a lot.

no doubt about that - I think I can get the tank off blindfolded in 2 minutes

btw, I found an identical like-new plug wired but unconnected in the relay box so I amputated it and grafted it onto the tank connection - that plug looked pretty sad.

3. a component missing in the case - a\what would have been a 1 inch diameter thing screwed in with 2 screws - I figure that since the bike ran like that, I'd leave it alone and in any case, I don't know what's missing

Is quite likely where the 3rd switching transistor goes for the K75.

You have done well.

That is what the forum is for. Now you are glad you did not buy a new one. That tank connector plug can be an isue. Let us know how its going.

The same bottom half of the housing is used on both models, so all of them
is made ready for three output transistors.

92KK 84WW Olaf wrote:That is what the forum is for. Now you are glad you did not buy a new one. That tank connector plug can be an isue. Let us know how its going.

Right after opening up the ICU again last night and NOT discovering anything obviously wrong with pin #7, I found a used ICU at Pinwall. I want to plug Pinwall here for all of you who are not aware of them.  I have bought quite a few parts from them for my K100 and Suzuki and always got excellent value and never a dud.  They test all parts and point out all damages, if any.  I paid $54 for the ICU and should receive it shortly.  At that time, I will advise the forum of the conclusion of my current problem.

In the meantime, thanks again to all of you who took such an interest in my troubles and helped to get to the bottom of them.

k

Klausmeister wrote:

92KK 84WW Olaf wrote:That is what the forum is for. Now you are glad you did not buy a new one. That tank connector plug can be an isue. Let us know how its going.

Right after opening up the ICU again last night and NOT discovering anything obviously wrong with pin #7, I found a used ICU at Pinwall. I want to plug Pinwall here for all of you who are not aware of them.  I have bought quite a few parts from them for my K100 and Suzuki and always got excellent value and never a dud.  They test all parts and point out all damages, if any.  I paid $54 for the ICU and should receive it shortly.  At that time, I will advise the forum of the conclusion of my current problem.

In the meantime, thanks again to all of you who took such an interest in my troubles and helped to get to the bottom of them.

k

Dear K100 Forum members

Based on the enthusiastic support I got from so many of you, I had another go at the ICU with emphasis on Pin 7.  It was a lot easier the second time. And so I had a closer look at the possible cross connections on the board and maybe found a couple.  Anyway, I resoldered the 21 connections and cleaned up really well with my little SS brush and a clean rag and an Exacto knife and guess what...it fired up right away and runs as sweet as a nut, or at least, as well as intended by the beemer bunch so many years ago.  How long?  Well, the bike is 30 years old and if it were a dog, that's 210 people years. 

Luckily, it's not a dog.

Cheers

ps - here's the link to the ICU I bought from Pinwall

http://www.ebay.com/itm/110211004188?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

great to hear

another k bike returns to the road ....with a great big smile on the new owners dial ...

cheers

I have bought gear from pinwall a few times and they have always been very good. The international postage has been a bit excessive at times but that isn't all their doing.

Now that is what we call a proper outcome. You saved $1300 and had a very positive experience. Hope you get to meet a few forum members now.

The $1300 saved entitles you to buy a beer and feel really good because now you know so much more about the K.

You're a braver man than me opening an ICU. Soldering is one of the Black arts as far as I'm concerned!

@RickG - Good to know theres a fix(er) for the ICU I have an old one gathering dust in case they become scarce. If so I'll suffer the postage!

Excellent news!

These are the type threads and thread originators I love....

People sharing knowledge and the OP actually posting the resolution so others can benefit.

88KE wrote:You're a braver man than me opening an ICU. Soldering is one of the Black arts as far as I'm concerned!

@RickG - Good to know theres a fix(er) for the ICU I have an old one gathering dust in case they become scarce. If so I'll suffer the postage!

hmmm...don't know about brave.  You need a smallish soldering iron and a desoldering pump - as I noted before, I bought one of those for around $2.50 so it's not a big investment.

There are 2 groups of 3 pins in the middle of the board (once you take out the 4 screws holding the top down.  While there, make sure the o-ring gasket is intact - if not, get another one.  Those 6 pins are easy to loosen but then come the 15 in 2 rows.  They are close together and you must get the solder away or they'll never let go.  I also used a stainless steel brush to wisk away some solder - you heat and once the solder is liquid, you brush quickly.  So, after a while, it should look like most the solder is removed but the pins will still be stuck.  Next, undo the 4 screws that hold the male pin section and gently move it - the idea is to break the last little solder seal.  I also pushed down on the pins to aid in that loosening process.  And it worked - twice.  Remember to extract the pin part (you'll see what I mean when you got it in your hand) in a radial motion out and up.

OK, so now the board can come off (after another 4 screws).  Mine looked quite pristine except for what looked like 2 little brown transformers (they may be something else) that the last person who opened my ICU had cemented with some epoxy stuff.  As I noted before, since the bike had run OK, I left that alone.  If I had new spares on hand, I would have replaced the grotty looking ones.

All I really found was dirt and grime (maybe old soldering paste?) that likely caused a short.  I cleaned that and put the thing back together.  Soldering the pins ON is pretty easy.

So there.

BMW should be ashamed to charge $1300 for that thing.  There's not much more technology than in a transistor radio - maybe less.