The K100 sidecar left me stranded today, and had to be trailered home.    In an attempt to didagnose it beside the road, I pulled all the plugs, which were wet, and then cranked it over a few revolutions to clear the cylinders. When I tried to start it again, I noticed fuel running out of the exhaust pipe where the muffler attaches to the header, so I pulled the fuel rail, and all 4 of the injectors are spraying the entire 1.5 seconds that the fuel pump stays on.  (and what seemed to be a large amount!)


Any ideas on this one??  

Thanks,
Ken

Seems to be working as intended.

If the fuel is not burnt it will come out as liquid from the exhaust after cranking the engine for a while and all the injectors fire at the same time.
Not sure about the spray staying on though.
Was that while the engine was trying to crank or when the ignition was turned on and the pump ticks over for those 1.5 seconds?

Rossko, You can just bump the starter, and all 4 spray for 1.5 seconds.


I've not really had time to research it yet, but the volume that they are spraying seems tremendous.  They are spraying a cone, and not pissing a stream however. 

ken

Ken F wrote:The K100 sidecar left me stranded today, and had to be trailered home.    In an attempt to didagnose it beside the road, I pulled all the plugs, which were wet, and then cranked it over a few revolutions to clear the cylinders. When I tried to start it again, I noticed fuel running out of the exhaust pipe where the muffler attaches to the header, so I pulled the fuel rail, and all 4 of the injectors are spraying the entire 1.5 seconds that the fuel pump stays on.  (and what seemed to be a large amount!)


Any ideas on this one??  

Thanks,
Ken

It sounds like your injectors are shorted to ground and so remaining open.  You should only have ground when running or cranking and then it should "flash" ground signal.  Verify power and ground, power should be constant.

are you sure that the temp sensor ....to the ecu ( not the dash dial) is connected properly

I seem to remember that  depending on the resistance coming from the temp sensor, it will cause more fuel to be delivered for the reading .
so a hot bike is very low in resistance and a leaner mix ...whilst a cold bike is up around the 3000 ohms region and supplies a much richer mix

If the temp sensor was open circuit ...could it cause this issue ?


its easy to measure on the old 8 valve units ...but unsure on the newer models

just food for thought
good luck

Ken try it with the plugs disconnected that way you then know if the injectors are stuck open with crud or being held open by an electrical fault.
If its an electrical fault leave only one injector connected to prevent too much fuel being around when testing or set up a test lamp in lieu of an injector but a test lamp probably wont light with the very short pulse time.

Steve & Charlie, thanks for the replies.  There does not seem to be any "flash of the ground signal" 
I've not checked the temp sensor from the ECU, a good suggestion. What is puzzeling to me is that the previous owner said this was why he 
parked the bike 4 years ago.  He had had it to the local BMW dealer, and they declared it fixed.  However he rode it about 70 miles, stopped for lunch and it would not restart, whereby he had it towed home and never got it running again.  (he had just purchased a new K1/EZS sidecar)

This same thing happened to me the night before I had to tow it home, but at that time it restarted, and you could tell from the exhaust smell that it had been flooded.  

I had ridden the rig 20 miles, ran into a shop, and when attempting to restart it about 5 minutes later, I discovered the above mentioned problem. 

I picked up a 12v. LED today, and made a fuel pressure gauge this evening so tests are in order! From the volume of fuel it is spraying in the 1 1/2
seconds that the fuel pump is on, I'd guess that the fuel pressure is staying around 60 but the test should show. 

Thanks again for the replys, this forum is such a help!   

Ken

RicK G wrote:Ken try it with the plugs disconnected that way you then know if the injectors are stuck open with crud or being held open by an electrical fault.
If its an electrical fault leave only one injector connected to prevent too much fuel being around when testing or set up a test lamp in lieu of an injector but a test lamp probably wont light with the very short pulse time.

Rick thanks for the response  that makes good sense!  I stopped and bought a 12v. LED lamp today, won't that work for testing the injector plugs to see if they are pulsing or not? (the starter doesn't spin it that fast, correct?

Ken

You may pick the pulse up with an LED but the pulse is very short at idle speeds. I cant be sure but I seem to recall that it was 406 microseconds which considering the injectors fire at every ig pulse (4 times in every 2 revolutions) then it is about 2 milliseconds opening for each firing cycle

Ken F wrote:Steve & Charlie, thanks for the replies.  There does not seem to be any "flash of the ground signal" 
I've not checked the temp sensor from the ECU, a good suggestion. What is puzzeling to me is that the previous owner said this was why he 
parked the bike 4 years ago.  He had had it to the local BMW dealer, and they declared it fixed.  However he rode it about 70 miles, stopped for lunch and it would not restart, whereby he had it towed home and never got it running again.  (he had just purchased a new K1/EZS sidecar)

This same thing happened to me the night before I had to tow it home, but at that time it restarted, and you could tell from the exhaust smell that it had been flooded.  

I had ridden the rig 20 miles, ran into a shop, and when attempting to restart it about 5 minutes later, I discovered the above mentioned problem. 

I picked up a 12v. LED today, and made a fuel pressure gauge this evening so tests are in order! From the volume of fuel it is spraying in the 1 1/2
seconds that the fuel pump is on, I'd guess that the fuel pressure is staying around 60 but the test should show. 

Thanks again for the replys, this forum is such a help!   

Ken

Ken, when trouble-shooting fuel-injector signal impulse I use something called a "noid" light. it has an led and resistors that imitate a fuel injector, and they come in various sizes for plugs specific to your application.  They can be purchased at an auto-parts store or harbor freight.  I am lucky because my son has a set and is a garage rat.

Ken F wrote:Steve & Charlie, thanks for the replies.  There does not seem to be any "flash of the ground signal" 
I've not checked the temp sensor from the ECU, a good suggestion. What is puzzeling to me is that the previous owner said this was why he 
parked the bike 4 years ago.  He had had it to the local BMW dealer, and they declared it fixed.  However he rode it about 70 miles, stopped for lunch and it would not restart, whereby he had it towed home and never got it running again.  (he had just purchased a new K1/EZS sidecar)

This same thing happened to me the night before I had to tow it home, but at that time it restarted, and you could tell from the exhaust smell that it had been flooded.  

I had ridden the rig 20 miles, ran into a shop, and when attempting to restart it about 5 minutes later, I discovered the above mentioned problem. 

I picked up a 12v. LED today, and made a fuel pressure gauge this evening so tests are in order! From the volume of fuel it is spraying in the 1 1/2
seconds that the fuel pump is on, I'd guess that the fuel pressure is staying around 60 but the test should show. 

Thanks again for the replys, this forum is such a help!   

Ken

yes indeed steve
we have seen these temp sensors be a real intermittent pain in the proverbial
the problem arises because of the atmosphere of the surounding equipment (just behind the radiator) and the difficulty to get in there .
worth testing and cleaning regardless

Charlie, I have been looking around, where is the coolant temperature sensor located on my 4-valve?  Thanks

There is 2 sensors one is for the gauge and is down on the water/oil pump and the other is left side behind the radiator on the outlet of the engine. It's a real difficult thing to get at and you need to remove the filter and the lower section of the air filter box and of course the lower of the fairing on the right side.
The 2nd one is the one you need to get at, if all you want to do at the moment is measure resistance you can do that by going to the wire at the ECU plug that goes to the sensor.
I dont have a circuit for a K100 4V so I dont know which pin to go to. On the K1100 it's a black/ blue wire and most likely is the same for the K1004V

Ok wise ones....I'm still stumped.  

It's been awhile since I've been able to work on the K100.  An old friend was operated on for throat cancer, and had no one to accompany him to the hospital, or provide care afterwards, so I made the ride up to assist.   

The fuel pressure is fine coming from the pump, and the FP regulator is doing it's job just fine, however pressure bleeds off to zero within 10 seconds of turning it off.  No visible leaks, so possibly the FP regulator is allowing it to leak back into the tank? 
.  
The 12v. LED works like a champ for testing injectors!  You can see the pulse, and after letting off of the starter button it stays lit until the FI relay cuts out, which I feel is where the problem lies.  The fuel injectors do exactly the same thing-they keep squirting until the fuel pump shuts off causing the engine to flood.  The injectors are shutting off just fine during the pulsing while cranking, so they are not failing to close off the fuel flow- it's an electrical problem.

From what I have learned so far, the ground (pulsating) to the fuel Injectors comes from the EFI computer.  Thinking possibly it was the EFI Computer I borrowed a known good one, and it operates exactly the same.  I intend to go and borrow the ICM also, and try that too.  

The problem persists with the plug disconnected from the butterfly valve also.

I'm not real good with electrical schematics, but could the FI relay be causing the problem with the ground staying connected after the starter is released?  

I appreciate the help thus far, and hopefully some of you may be able to provide some further insight.  

I've not checked the connection to the temp sensor yet, but by looking at the schematic, I fail to see how that could be causing this problem.
As I said though, I'm not to good with them.  This was an intermittent problem for the previous owner also, the bike left him stranded a few times, but would usually restart after a period of time.  This has also happened to me twice, but this time the problem persists, which is good! 
At least you can diagnose it when it's not working properly.  

Thanks again,
Ken

For a K100 2v, the connections to the computers are:

EFI:


Electronic ignition:

Well, I've been working on this cussed motorbike for almost two weeks every evening, and weekends.   Still no joy.  

I've cleaned all connections, changed hall sensors twice, L-jetronic, Electronic Ignition, traced wires, ect, ect, 

My problem (to save having to go back through the thread) is that the injectors pulse while the engine is cranking, but when you take your finger off the start button, they do a continuous spray until the FI relay shuts off. there by flooding the engine.  

My thinking is that this should not be happening. It was definatly flooding the bike to the point where it would not even fire, and fuel was running out the connection of the header pipes and the muffler.   For the life of me I can not figure out why the injectors are staying grounded after the engine quits rotating. 

I've done all the checks for the electronic Ignition, and it tests good.  I've even tried substituting for a known good one.  Same with the computer.  I've not tested the air meter but fail to see why it would cause this. 

 Starter relay is one thing that might possibly cause it?  

Maybe it's normal for them to stay on after the start button is released and I'm chasing nothing?
I dunno....my mind is turning to mush!  lol

I would sure welcome any advice anyone has to give!  

Thanks for listening to me vent.

Ken

When the fuel pump stops after the 1.5 seconds do the injectors stop immediately or do they slowly drain the pressure from the rail and pump?
There is a black/yellow wire on pin #4 of the ECU plug if you disconnect that wire does it still happen?

Thanks for helping Rick!  

It's been about a week since I have had the tank on, and I've been testing it with a 12v. LED. at the injector plug.   In all honesty I didn't pay attention at the time, but will put the tank back on and check first thing in the morning.  What I recall is that they stay open until the relay kicks off but by then almost all pressure is gone from the rail, (down to 10-15 psi.) and pressure continues to bleed off somewhere down to zero.  

The Black/Yellow wire has been replaced previously, and now is run on the outside of the harness. disconnecting it will be a piece of cake, and will do that also in the A.M.  

Thanks Again, 

Ken

Rick,

Once the FI relay shuts off, the injectors close (power shuts off).  By This time however almost all of the pressure is relieved from the fuel manifold.  

By disconnecting the Black/yellow wire from pin 4 at the computer, the pulsing of the injectors is no longer there, and the run-on after you stop cranking is also gone.  When the relay kicks out, there is an instantaneous flash (12v. by voltmeter) on the LED that I had plugged into one of the injector plugs, but the constant earth after removing your finger from the start button is gone.


I'm going to go sit down with the schematic and try and understand what disconnecting this wire did, and see if I can make sense of what it means!  lol   I'll check back in periodically for a response.

thanks again!


Ken

Rick, I got nothing.  

Strictly a guess would be either the starter relay, or the FI relay.

Ken

The injection is working by the ECU putting the return wire to ground every pulse, whilst they have contrinuous 12V provided. If the injectors stay open you have either a ground issue with the return wire (that could be inside or outside the ECU) or the ECU itself is faulty. To my knowledge there is nothing between the injectors and the ECU. From what you've told us there is pulsing during starting, but continuous flow when running. There is a 'start assist' when the TPS is closed. Can you try with the TPS slightly open (or disconnect the plug) and tell us what happens?

Thanks for the reply Rene.   The symptoms are the same with the TPS unplugged.  
That was one of the first things that I did, and have tried it several time since during my attempts to diagnose.  

I believe that the computer can be eliminated as a problem, as I have tried two different 
ECU's from known running bikes, which both act the same as my original one.  
Ditto with the Ignition control module.

If there were a grounding problem in the harness to the injectors, they would not pulse during cranking would they?
I believe that something is sending an erroneous signal to the computer, telling it to keep them open but I'll be damned If I know what!  

Ken

I have a feeling it is to do with the Black/Yellow wire that has been replaced by an external wire. That wire goes from pin 4 on the ECU to the 2pin plug on the start relay, what I am wondering is has the wire been disconnected from the plug at the starter relay and why was it replaced and what was wrong.
I would be inclined to open the wiring harness and check out what is going on if anything.
I am not sure how thw enrichment feature actually works but if I was building an ECU I would make it give a short squirt of fuel rather than up the metered dose at start and given that the Black/Yellow wire is the one that signals the ECU to enrich the mixture at startup I would be inspecting that area very carefully.
This is certainly an intreauging problem and very fustrating for you.

Rick, that was my initial feeling too.  However, they have broken open the connector at the ECU, and spliced onto the Black/yellow.  From there, it runs to the Start Relay, as shown in the schematic, then on up to the ICU, as it is supposed to.  

I've thought about ordering anther wiring harness from ebay, and just replacing the whole thing, but this really has me wondering where the problem is.  I guess I'm kind of stubborn that way.   

Your suggestion of cutting the harness open is probably a good idea.    I've already tried checking each wire in the FI system to ground, and to every other one to see if I could find a short but no luck. I guess that would be a good project for tomorrow.....cut the harness open!  

Thanks for everyones help thus far.


Ken

You may have already done this but is the B/Y wire removed from the circuit because it may have been open circuit and the other replaced it but also if it was short to something, whatever the reason may have got worse and now be causing more grief. Actually whatever caused the original problem may just be getting worse and involving other wires.

Well, here I am again 5 months later, spring is coming and still have the problem.  The wife's Audi has gotten in the way as it needed some repairs also, and took priority.  So many projects, and so little time.......

I have cut the entire wiring harness open, and found no problems though it does make it much easier to trace wires!!  

I bought a noid light which does make things much easier.  

I've also replaced the temp switch as Rick suggested, no difference, but at least there is a new one in there now! As hard as it is to get to, this will be a bit of peace in the 'ol noggin.  

I have made two discoveries today which may help.  The first (which will enable me to at least ride the bike) is that if I switch off the kill switch at the exact time I release the start button, the injector run-on does not happen.  However, this is not the solution as the first time you forget, you are flooded again.

The second thing I found is that with the bike in gear, and the clutch pulled in, there is no pulsing at the injectors (when cranking), but when you release the start button, the noid light comes on & remains lit until the F.I. relay cuts out, again which would flood the engine.  Obviously there is a problem with the clutch switch, as it seems to be working exactly opposite of how it should. 

At this point, I was forced to quit working on it, but does this give anyone insight as to whether this might be the problem?  I did not test the function of the switch with an ohm meter, nor test the diode in the instrument cluster.   Not sure if this is the culprit or not...

Thanks, 
Ken

just throwing this in the mix


might be a good time to clean up the ignition switch ??

we have seen some very weird interactions when the switch is higher than expected resistance  ( bound to happen over time ) or voltage is not right getting to the relative ecu

just makes sense to this ol bloke when ecu issues  start up

also ...please ... clean up the fuses and holders ...

the fuel ecu wont switch properly unless it gets the right voltages

just  question ...did you measure the temp sensor at the fuel controller ...under the seat after replacement ...look at pins 10 and ground ...there is a graph in the "efi trouble shooting guide " relative to ambient temperatures ...

we know if they are approaching open circuit, flooding results ...the start process is complicated ...no need to make it harder . eh ?

SteveK1 wrote:Charlie, I have been looking around, where is the coolant temperature sensor located on my 4-valve?  Thanks

in the water stub steve ,,just behind the radiator  and in front of the throttle bodies

sorry i missed this earlier ....

the 4 valve works to the motronic unit with just 2 wires (in 16 valve motors and engine management stuff ) quite different to the older 2 valve motors (which use 2 separate paths with an earth reference
so basically there is no earth reference on the 16 valve units _ this earth reference on the 2 valve motors allows for the sensor to feed the temp sensing relay for fan control .....and fuel injection control as separate entities ....I have found that a bad earth to the stub has affected fuel consumption at a minimum

hope that helps

Charlie, yes I have checked the voltage on pin 10, but it's been a while, so will do again.  Thanks for the reply & the suggestion about the switch.
Will try that too.   

Being from the wrong side of the pond, What in the world is a stub?  

"I have found that a bad earth to the stub has affected fuel consumption at a minimum"


Ken

maybe this will explain ken



the water stub bolts to the head and then distributes the water to the bypass tube and the main radiator feed  also housing the Temperature sensor

when I did mine I found corrosion both on the thread of the sensor ...and a pitted washer sealing the parts

I actually replaced the washer with a copper one ..which I tinned all over (to act as a buffer for the dissimilar metals) and soldered a wire which I took to the main under tank connector for earth (which just happens to be a good periodic testing point )

by the way you would be using continuity (ohms) to test the sensor at the fuel injector computer (pin 10 )and the other leg to a good earth,  set the meter to 10,000- 20,000 ohms for cold ...as it warms then switch to 2,000 ohms,  if it is a scaled meter .

I assume that the connections to the computer are clean and free of corrosion ..if not clean them up then apply "deoxit " to both the socket and pins

Ahhhh....ok Charlie!  And here I thought that was one of your "English" terms that I wasn't familiar with!  LOL

Yes, I've changed to a new Temperature Sensor, but have not yet actually installed it into the stub.  I have only plugged it in and attached a jumper wire to it and the frame.  Every terminal with a connector on the bike has been cleaned & deoxed.  (I don't think thats a word!) 

The elderly couple who gave me the K100/EML were English.  He retired as a Mechanical Engineer from Rolls Royce.  I often tease him about our 
"language barrier".   Unfortunatly with heart trouble the last couple of years, he no longer feels safe to ride, but said he wanted me to have the rig as it was hand built by him, and his daughters had grown up in it, so it was an important part of their family.  
 I watched a very interesting show on the History Channel a couple of weeks ago about why there was such a difference between England's
English, and "English" which is spoken here in America.  It all had to do with the massive immigration which occurred in the mid 1800's.  Many English, Irish, Scottish, Jewish, Italian, ect.  brought their own unique expressions, and linguistic terms with them which became integrated into our language over time.   I had always wondered why the difference but I guess had never put 2 & 2 together......


thanks again Charlie for your help.  I'm planning to get back to it tomorrow night.   


Ken

As Oscar Wilde (Irish Playwright) once said "two great nations separated by a common language"

Ken F wrote:Ahhhh....ok Charlie!  And here I thought that was one of your "English" terms that I wasn't familiar with!  LOL

Yes, I've changed to a new Temperature Sensor, but have not yet actually installed it into the stub.  I have only plugged it in and attached a jumper wire to it and the frame.  Every terminal with a connector on the bike has been cleaned & deoxed.  (I don't think thats a word!) 

The elderly couple who gave me the K100/EML were English.  He retired as a Mechanical Engineer from Rolls Royce.  I often tease him about our 
"language barrier".   Unfortunatly with heart trouble the last couple of years, he no longer feels safe to ride, but said he wanted me to have the rig as it was hand built by him, and his daughters had grown up in it, so it was an important part of their family.  
 I watched a very interesting show on the History Channel a couple of weeks ago about why there was such a difference between England's
English, and "English" which is spoken here in America.  It all had to do with the massive immigration which occurred in the mid 1800's.  Many English, Irish, Scottish, Jewish, Italian, ect.  brought their own unique expressions, and linguistic terms with them which became integrated into our language over time.   I had always wondered why the difference but I guess had never put 2 & 2 together......


thanks again Charlie for your help.  I'm planning to get back to it tomorrow night.   


Ken

ken ...all the above happened here also .....just some 100 or so years later...giggles  

out here, we all celebrate our differences between nationalities  usa, gb , Ireland Canada, Italy, greece  and the list goes on and on ...and for the most part we have an undeniable affinity across this big planet with other folks .

up until the 1910s (first world war) ...we were dependant on "old blighty"(England )  for all law and social etiquette, so many spoken word relationships are solidly based on "England" English concepts

things change and so do population ergonomics ...but we (aussies ) are still often stunned by the lack of knowledge of even where Australia exists on the world map.
we may be small but carry an awesome reputation ...and for some folks well deserved .

I do get worried that some of the things we see out here in relation to world geography become so "internally orientated " so that folks have no real idea about other countries and where they are, what they represent etc ...I guess for some it don't matter.

but being a thinking bunch of "blokes" (aussie for "male over legal age" )  we would like to absorb some of each others culture and opinions
but sometimes we encounter a really staid opinion from some fellow members ....in what, how, and the only way that things should be done, measured or tolerated .

I guess what i'm saying is that we all have different ideas on terms and measurements not only but including procedures and absolute tolerances, delivery of opinions etc .

I guess we get a feeling for these things and after a little while it all forms a great mass of collective knowledge and interchangability between the various versions of out shared "k" language

I "recon" (aussie for "opinion well founded" )  there enough of us old and knowledgeable folks who have turned spanners long enough  to know "something " of standard definitions both mechanically and electronically ( for some ) to have an opinion. on how things could be made better .....yes the original design exists but to german expectations..for many of us it needs some modification to local ergonomics to prove reliable and comfortable motorcycling .

our old mate "sidecar paul" (pommie ) often shows brilliance in the mechanical engineering solutions "robmack" (canuk) shows devine electrical solutions "duck" ( American ) has a real working knowledge of most things , "rick g"(aussie)  has a great knowledge base of all things and "inge-k" (sweden) is the reference book on all things.. k bike
and are often here to share the "knowledge " and we are in their awe .

our esteemed leader "crazy frog " bert to some, puts up with us lot,  and hosts one of the most single handed wealth of knowledge, compassion and helpful forums in the English language that I have had anything to deal with so far ...

there are moderators under the shelves that silently move stuff around ...usually into the correct relative forums ,,,and offer feedback to the admin team ..."crazy frog (canuk)  and k-bike" (new Zealand ) 

jest is a strong feature of the aussie character and so with the irish  ( you often see aussie banter going on in here , join in if you get it ...or ask..!  we don't bite ...much ...grin ) ,,,,...so don't take anything too heartfelt ...and where possible laugh out loud ....there are some screemer contributions made by many across the wide world of k bikes in here .

so enjoy .... is all I can say ..there are fantastic insights always here

and our languages dont differ too much that we cant be understood ...

note if your a punctuation and grammar - spelling critic-nazi   "piss of now " 

communication isn't about text dexterity and manipulation of the commas and full stops ...

the message does get through the bs 
cheers !!!

Ken in this thread  https://www.k100-forum.com/t6786p100-problem-starting we found similar problems to your ingear clutch in findings, It was traced to the FI relay and when swapped with the horn relay solved that particular issue, I believe it was the 87 pin on Ed's bike carries 2 greenwith red stripe wires. They had no power when starter button was pushed but upon release they were powered and shotfuel for the 1.5 sec's as you mention. That's for the in gear IE no green neutral light showing clutch in setup on Ed's 88 model, you may have different relays if its an earlier model.

yeah that was good find keith ...onya mate !

Otherwise have (another?) good look at the wiring. The injectors are getting 12V constantly and operate by the FI module switching then to ground/earth :-). If there's any issue with the wire coming from the injectors to the FI module (shorting to frame or ground) you might get a similar effect. This off course assuming the FI module is OK.