BMW K bikes (Bricks)

You are not connected. Please login or register

View previous topic View next topic Go down  Message [Page 1 of 1]


1Back to top Go down   ECUs never fail... Empty ECUs never fail... Mon Mar 09, 2020 3:05 pm

Suzi Q

Suzi Q
Life time member
Life time member
Every once in a while there'll be a 'bike not running' thread, and the OP will looking narrow-eyed in the direction the ECU...
I'll head for the keyboard, probably post a picture of a mashed up, highside-then-hit-a-tree K100 ECU and point out that the thing still carried on working once I'd bashed the ally casing straight again. Nope, nobody need worry about the ECU.

So after three days of troubleshooting, everything, on the Madass, turns out it was the ECU, that had gone poorly with some very weird symptoms:

Bike started & ran fine, but misfired (just like a HT/plug cap/spark plug fault) at 5500rpm. Coughing and kicking and refusing to rev any higher (no matter how much I tried, ahem).
Rode it for a while like this, thought it was the damp weather - must look at the HT leads etc.
Bike would rev to 7-8 ish if not under load - i.e. testing in the garage.
Plugs not bad, maybe a little sooty.
Exhaust gas nice and clean.
Bike would nearly rev fully out if I stuck my hand 3/4 over the AFM inlet, whilst fully opening the throttle.
Bike would do the same if I manually turned the AFM vane fully open.
(Okay, so the last couple of points suggest a weak mixture - I replaced the blocked & collapsed 30 micron fuel filter (yay I've found the fault!) and this gave NO improvement, gnash gnash gnash)

FINALLY, swapped the they-never-fail ECU and bingo.
Took the old ECU to bits and saw this....

ECUs never fail... 01115

....which is what I'd expect to see inside a thirty year old ECU - I have no idea what I'm looking at lol  Very Happy


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

2Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Mon Mar 09, 2020 3:26 pm

duck

duck
Life time member
Life time member
I know of one that failed.  While the K75 was sitting for years some tiny ants decided to make a home in it. affraid

(Sorry. No pics.)


__________________________________________________
Current stable:
86 Custom K100 (standard fairing, K75 Belly pan, Ceramic chromed engine covers, paralever)
K75 Frankenbrick (Paralever, K11 front end, hybrid ABS, K1100RS fairing, radial tires)
86 K75C Turbo w/ paralever
94 K1100RS
93 K1100LT (x2)
91 K1
93 K75S (K11 front end)
91 K75S (K1 front end)
14 Yamaha WR250R
98 Taxi Cab K1200RS
14 K1600GT
http://www.ClassicKBikes.com
    

3Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Mon Mar 09, 2020 8:28 pm

RicK G

RicK G
admin
admin
The only ones I have encountered that failed all were when water got in and they were turned on before being dried. Usually from using a pressure washer.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1998 K1100 LT, 1993 K75 RT, 1996 K75RT, 1986 K75 GS, 1979 Z1300 Kawasaki
    

4Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Tue Mar 10, 2020 3:52 am

Suzi Q

Suzi Q
Life time member
Life time member
In my dimly-lit view of all things electronic, these kind of things tend either to work fine, or not at all. The 'let's-pretend-I'm-a-faulty-spark-plug' had me fooled, which isn't hard I suppose.

Can't even blame vibration/faulty solder joint/broken track, 'cos the thing didn't work properly even when I was nursing it in my hands.

Oh well, fixed it with a new one borrowed from the project bike. Make a good spare for anyone who doesn't ever rev things past 5k/has too many points on their licence/etc.

(Seriously, only posted this in case the symptoms help future troubleshooters Smile )


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

5Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Tue Mar 10, 2020 6:03 am

Dai

Dai
Life time member
Life time member
Chris: it  sounds like you're describing a duff capacitor (or possibly resistor) in the advance curve circuit. I've not had a K ECU fail like that, but your description exactly matches a problem I had with with a Pirahna ignition system on a Guzzi 1000SP some years ago (minus the MAF bits of course!).


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

6Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Tue Mar 10, 2020 6:24 am

GF Wollongong

GF Wollongong
Life time member
Life time member
It's a pity you can't plug it in (on the garage bench) and power it up to try and identify the fault.

My father did this with a TV (I should have thrown out), then with the back off, got the WD40 sprayed away. Then a little crackle and wisp of smoke rose up. Loose connection found ... little bit of solder and the TV was good until i finally got rid of it. 

Don't think I've bought a TV in the last 20 years. People keep giving them away.

Then again, maybe you can give it 12V through the appropriate pins and give it a light spray (warning: I am NO electrical expert ... defer to wiser heads)

Other than that, surely it's a capacitor as Dai was pointing to

If you need one, I am pretty sure there's one in the spare box. Postage might be about 2 weeks

PM me if no joy

GF

    

7Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Tue Mar 10, 2020 7:40 am

Suzi Q

Suzi Q
Life time member
Life time member
Thanks guys. I’ve just had a close look at the capacitors and one does look as though the soldered connection might not be 100%. So thanks for heads up.
Now where’s that five hundred watt soldering iron....?


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

8Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Mar 12, 2020 6:10 pm

Snod Blatter

Snod Blatter
Life time member
Life time member
What kind of capacitor are you looking at Chris? Can we see the solder joint?

I'd imagine Dai is alluding to dried up electrolytics..?


__________________________________________________
1989 K100RS SE ABS 8v  VIN: 0149214
Others: 1.5 x Honda CBX250RS-E, '94 CB250, '95 TRX850, '16 Z250SL
http://justbikethings.blogspot.co.uk/
    

9Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Mar 12, 2020 7:34 pm

Dai

Dai
Life time member
Life time member
More or less. Sometimes they just rot through the dielectric medium and short out.


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

10Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Fri Mar 13, 2020 5:54 am

charlie99

charlie99
VIP
VIP
can you take a pic of the underside chris ? especially around the external connector area .


don't forget that electrolytic capacitors dry out internally ...its a natural thing , with work that they get and the smaller the value the higher the percentage change in value

not hard to find to replace with standard values used commonly in bmw stuff  but I only see 1 of such in this pic , most are polyester types by the look , mostly glued down , if you had the glue, fail leg - lead fail could happen through vibration

but does sound as if its a supply issue , or possibly a rise time issue through a conditioning circuit area caused by a "dry joint "  (badly soldered or stressed solder joint )


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%OECUs never fail... Au-log10

'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
    

11Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Fri Mar 13, 2020 12:21 pm

Suzi Q

Suzi Q
Life time member
Life time member
Here's the best pic I can manage of the only suspect-looking joint I could see. It's directly top left of the upper square cutout in the board. I've scraped a little of the flux/whatever away.
ECUs never fail... 01410

It's one of the legs of this capacitor, centre picture.
ECUs never fail... 00516

Which, although the writing on it is obscured by an adjacent component, appears to be the same values as this - 2.2mf, centre picture:
ECUs never fail... 00616

The board itself seems quite twisty, either heat or age:
ECUs never fail... 01411

I don't suppose this could be the culprit (it's about the only component on there whose function I understand lol!)
ECUs never fail... 00913

Thanks for your help. A replacement arrived today from German Germany, blue label, different part number, all-metal casing. I guess it'll work on the new bitsa project. I'll definitely have a crack at fixing this one though, if you think it's worth a try.
I also started having those mad thoughts again - why wouldn't a K100 ECU work a K75?


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

12Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Fri Mar 13, 2020 3:53 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
chris846 wrote:
I also started having those mad thoughts again - why wouldn't a K100 ECU work a K75?
It may possibly because the Hall Sensor signals are at different points in the rotation of the crank(120 vs 180 degrees). 

It's possible that the airflow sensor has a slightly different door deflection based on only three cylinders pulling air in the K75.

The thought has crossed my mind as well because I see my K100 ECU through a somewhat jaundiced eye and it seems that used K75 ECU's are a lot cheaper than K100 units.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

13Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Sat Mar 14, 2020 4:31 am

Suzi Q

Suzi Q
Life time member
Life time member
Well, Mr Point Seven Five,
I'm going to try!


The Jetronic takes its signal from the ignition module outputting a cylinder 1 firing signal, and it bank fires all three/four injectors once every engine rotation.
I'm guessing the 3-coil 75 is still wasted spark, same as the 2-coil 100, because there's no camshaft sensor on jetronic.
So, in the land of the dimwitted at least, both the triple and four jetronics output an injector pulse of a duration mainly mapped to engine revs, but also modified according to AFM. The duration of the pulse needn't be massively different between a triple or a four, 'cos each injector only serves one cylinder.

As you have said, it's the modification-according-to-AFM that could make a difference - a four will have more airflow at a given rpm than a three, so a four cylinder jetronic on a triple, will think that the throttle isn't open as much as it actually is, and maybe run things a bit leaner than they should be. Likewise a triple jetronic on a four, will think that the throttle is open wider than it is and put a bit too much fuel in.

All of which could be crudely offset with an adjustable FPR.

But why? It's seven am, and this kind of thinking is just perverse.


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

14Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Sat Mar 14, 2020 6:33 am

Stumpy

Stumpy
Silver member
Silver member
Mr chris846, you have motorcycles on the brain. I also find that sometimes you will wake up in the middle of the night and think about your motorcycle. It means that you need someone who will understand your situation and offer help.


__________________________________________________
BMW K100RT 0095857
    

15Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Sat Mar 14, 2020 3:05 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
As I struggled recently with my K100RS overfueling issue I began to daydream about putting a motronic in place of jetronic ECU. 

Swap the engine harness, ignition modules and ECU, replace the MAF airbox with the Motronic airbox and throttle position sensor.

It seems so simple...


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

acftfliehr

acftfliehr
active member
active member
chris846....  I had the same issues on the freeway on the Bay Area California that started acting up at the end of February ...  (It may had been acting up but barely noticeable).


At speeds of about 140K, the engine would stop producing power all of a sudden...  Then when it slowed down a bit would come back on and run for a while and the same would happen if you started to demand more speed / power.


I played around with it a bit and noticed the tach was always alive indicating proper engine RPM.  Also, whenever it restarted, never received backfiring from a fuel delivery without spark situation...  


So I thought just like you...  ECU's never go bad...   And changed out the fuel pump ( 20 year old Bosch Unit)   Bike is a 1985 K100RT I've owned since new and use it for travel commuting and all other sorts of needs for theses past 36 Years....


Nevertheless the pump didn't solve the issue...  Changed out the Jetronic ECU and I've put 400 Miles on it since with no recurrence of the issue..  I've taken mine apart to compare with your pictures and it does look differently in placement of some of the chipsets etc....  Nothing appears bad or cold solider joint obvious issues...  How do you post pictures on this?


Also does anyone repair these that you know of?  10 Years ago I used an outfit in the Netherlands that worked on the ignition module I thought I had problems with (another intermittent shutdown, but all power would cut off and then a backfire - Isolated it to the ignition switch, that gotcha can cause a lot of grief!!!)


Another strange thing, when I changed out the ECU, the one that repaired the issue was idling at 500 RPM but in all other cases normal, brought the Idle up on the fuel rail no issues.... 

    

17Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Mar 25, 2021 7:22 am

Dai

Dai
Life time member
Life time member
@Point-Seven-five wrote:As I struggled recently with my K100RS overfueling issue I began to daydream about putting a motronic in place of jetronic ECU. 

Swap the engine harness, ignition modules and ECU, replace the MAF airbox with the Motronic airbox and throttle position sensor.

It seems so simple...
Actually started buying parts to do just that some time ago... then found out the Moronic badly over-fuels the 2-valve engine in the mid-range. It's buried on here somewhere - the guy who built the JJ Cobas replica did all the research.

Ringfad became the unexpected recipient of a Moronic and cables Very Happy


__________________________________________________
1983 K100 upgraded to K100RS spec, 1987 K100RT
Others...
1978 Moto Guzzi 850-T3, 1979 Moto Guzzi 850-T3 California,1993 Moto Guzzi 1100ie California
2020 Royal Enfield Bullet 500
    

18Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Mar 25, 2021 8:28 am

robmack

robmack
Life time member
Life time member
You'd be much better off adapting a MegaSquirt or MicroSquirt EFI to the 2-valve engine.  There is a thread over on the other K-bike forum by wmax351 which discussed that.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

19Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Mar 25, 2021 8:55 am

Ringfad

Ringfad
Life time member
Life time member
BSK SpeedWorks - BMW K Series Engine Management Package

Most of my bikes cost less than this, but I have seen it fitted to a racing K1


__________________________________________________
ECUs never fail... Ir-log10

   ;BMW; K100RS Style Black 1987 105K Km     ;BMW; K1 Black 1993 60K Km     ;BMW;     K1100LT (Swiss) now a RS     ;BMW; K1 Blue 1990 25K Miles
    

20Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Mar 25, 2021 10:48 am

Laitch

Laitch
Life time member
Life time member
@robmack wrote:You'd be much better off adapting a MegaSquirt or MicroSquirt EFI to the 2-valve engine.  There is a thread over on the other K-bike forum by wmax351 which discussed that.
Here's a description of the result . He sold it. Last time he posted, he indicated he adopted his uncle's 1998 Moto Guzzi California and was enjoying the ride. Smile


__________________________________________________
1995 K75 81,000 miles
ECUs never fail... Usa-lo10
    

21Back to top Go down   ECUs never fail... Empty Carmo Mon Mar 29, 2021 9:49 pm

acftfliehr

acftfliehr
active member
active member
Here is the outfit that inspected and repaired my Ign. Module in 2013 they also repair all the other Hi Tech stuff that is no longer supported by BMW...

https://www.carmo.nl/index.php?main_page=index

    

22Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Apr 08, 2021 2:58 am

gabriel

avatar
Platinum member
Platinum member
Hi

Did you check the flux capacitor??


__________________________________________________
;BMW; 1984 BMW k100..frame number 6228?
1992 BMW K75s
    

23Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Apr 08, 2021 3:30 am

Suzi Q

Suzi Q
Life time member
Life time member
DiLithium-Iron crystals is on another thread, about batteries.
Do pay attention!


__________________________________________________
Sometimes I'm not really Suzi Quatro.
    

24Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Thu Apr 08, 2021 4:34 am

tinyspuds

tinyspuds
Life time member
Life time member
chris846 wrote:Do pay attention!

No one was expecting him to go for the juggler Very Happy


__________________________________________________
1985 BMW K100RT + Hedingham HUB and LL’s. VIN 0028106. (Not blind to the irony of an April 1 production date).
1986 K100RS in boxes. VIN 0141918.
1954 Royal Enfield 350 Bullet. Original.
    

25Back to top Go down   ECUs never fail... Empty Re: ECUs never fail... Sat Apr 10, 2021 6:32 am

gabriel

avatar
Platinum member
Platinum member
@Suzi Q wrote:Thanks guys. I’ve just had a close look at the capacitors and one does look as though the soldered connection might not be 100%. So thanks for heads up.
Now where’s that five hundred watt soldering iron....?

Hey Marty!

A 500 watt soldering iron is overkill, even for a flux capacitor..


__________________________________________________
;BMW; 1984 BMW k100..frame number 6228?
1992 BMW K75s
    

View previous topic View next topic Back to top  Message [Page 1 of 1]

Permissions in this forum:
You cannot reply to topics in this forum