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1Back to top Go down   Starting problems on a 87 K100  Empty Starting problems on a 87 K100 Wed Jan 06, 2021 7:00 pm

Ccanov

Ccanov
active member
active member
Hello!
 
I recently bought a 87 K100 (produced in 08/86) which did not start. The previous owner left the motorcycle in the garage for three years, but he said that was working fine before that… who knows. I decide to try, the price was good and always want to do something like this, so..... why not give it a try? 

After a few days checking, reading, and trying to make myself familiar with all the components, I decide that was time to start with the funny part.. I keep reading all kind of trouble shooting posts to get different ideas (i did not try the transmission oil on the throttle body yet..) but I am going to keep looking for info, just adding my own post so you can hear the bike and maybe help.

Now… I have been following the Bertrand Vogel (Crazy frog) troubleshooting guide during the past weeks trying to figure out what was going on. 

The starting point: motorcycle cranking but not start to keep idle. The lights are on, when I click the starter light off so looks good. In the video I keep the starter button depressed. 


What I have done:

  • Replace fuel pump, fuel filter, fuel pressure regulator and external fuel lines (PO had these parts new, so I prefer to start with the new parts to remove them from the equation)
  • Replace crank breather (kind of z hose from the block? to the airbox?) 
  • Replace the rubber between the throttle body and the black box.
  • Check tank conector, ICU and EFI connector. All cleaned with a contact cleaner. 
  • Fuse box (all ok) / Relay (I hear clicks in there 😊, my bet 90% they are working fine, but I should learn to test them)
  • Clean the grounds (frame, gearbox, and coils)
  • Idle switch (I hear the click when I turn the throttle, so I leave it like that)
  • Fuel Injectors, I removed the injectors and clean them with the carb cleaner spray and a kind o tool on amazon that comes with the connector to the battery, and a kind of plastic to put in there the injector. More than clean, I just want to double check that I have some kind of spray from then and were not broken... I have the spray when I activate the contact.
  • Air flow meter: test the resistance with the temp variation at home, and also the different pin combinations (at the air flow meter contacts, not the connector). The value changes if I move the vane. Pin 7-5: 102, Pin 7-8: 357, Pin 8-5: 358, Pin 8-9: 208)
  • Coils: for both coils I get the same values: 2.3 primary, 9.9k on the other, secondary?
  • Compression test: 165psi.
  • Measure valves clearance: all within spec.
  • Hall sensor, I had a new one, so I mount it just to discard that piece too. I was scary testing this part, because looks like its easy to break, so I mount the new one.
  • EFI Connector:

                - Pin 13 (ground), I have 0.3 - 0.4 ohms but not 0.
                - Pin 10 (water temp) I have 3.3k ohms (I guess that its cold the water or is there something else I should check here)

  • New plugs NGK D7EA (from any reason PO has Iridium NKG something...). Plugs or ignition wires are plugged properly, and I also check for spark with a “spark tester”.
  • So far, and to keep it simple, i did not mount back the airfilter box, so if i need to access some places its easier. I have the AFM connected but without the box, i guess i do not need it to make it work, but just so you all have the same info. I will mount it as soon as the motorcycle works and after a good clean. Unless you guys told me that I need to improve the airflow or something like that. I assume is just for the filter, but i may be wrong.


After all this measurements and replacements, I remembered that the owner told me that he move the airflow meter Allen screw (5mm), and also the throttle body screw (the one in the middle to adjust idle), so I am not sure what is the default position for the screws, or is trial and error...

I went with the trial and error (for the air meter) and starts for one time for 25 seconds at idle, and that’s it, no more starts 😊 So… should I close it and open 2 turns?

I am not sure how this motorcycle usually sound, I record a video for the 20 seconds with the sound, to be honest I did not expect to get it started, haha probably you guys can tell something else from the sound and smoke (taking into consideration that was not started for 3 years) 




Any help is welcome.
Thank you so much.



Last edited by Ccanov on Wed Jan 13, 2021 10:16 pm; edited 3 times in total (Reason for editing : Updating with more testing (compression, valve clearance) sme parts replaced.)


__________________________________________________
BMW K100 (K589)
    

2Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Wed Jan 06, 2021 8:59 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
From the cheap speakers on my laptop, your bike seems to be running okay.  You say it won't start after running for your video, is that correct?

I would pull the spark plugs and look at them.  Sometimes when an engine sits for a long time the piston rings will stick in the grooves and you will get low compression, and maybe a bunch of oil leakage past them into the combustion chamber. 

As far as the low compression, that usually sorts itself after running for a while.  You can help it by adding some Marvel Mystery Oil to the fuel to lubricate the cylinder walls and help loosen the rings.

If the rings are letting oil past and into the cylinder, your spark plugs may be fouled and not firing properly.  The only way to tell if that is happening is to pull them out and look at them.

Since you say the previous owner may have messed with the AFM air bypass, it might be worthwhile to reset it to the factory setting. 

If the plugs are fouled, clean them and try again.  If you have access to the flapper in the AFM, you might want to open it a little and shoot a little starting fluid in there to see if it helps start the engine.


__________________________________________________
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
    

3Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Wed Jan 06, 2021 11:10 pm

Ccanov

Ccanov
active member
active member
That’s right, after the stop I adjust the airflow meter bypass screw to set it to what I thought was the default value (close and then 2 full turns out) and same thing with the idle speed adjusting screw in the throttle body (one in the middle). I don’t know the default for this one...

I’ll check the spark plugs tonight and get some pictures. And also try to set the screws with the help of the starter spray, I think that I have a bottle.

Thanks! At least looks like the icu an le-jetronic are ok.



I’ll try to find out how to


__________________________________________________
BMW K100 (K589)
    

4Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 12:44 am

Ccanov

Ccanov
active member
active member
Ok... I try to set the airflow screw 2 turns CCW from close ( close = max down), and the one in the throttle body kind of 1mm when the choke is in the first position. 

Also, I forgot to mention in the first post that when it was idling, if I touch the throttle to rev it, the engine stop.

Here are 2 pictures of the spark plug 1 (1 to 3 look the same, so just one picture)

Starting problems on a 87 K100  Image010

Starting problems on a 87 K100  Image110

Here are 2 pictures of the spark plug 4 (looks darker to me)

Starting problems on a 87 K100  Image211

Starting problems on a 87 K100  Image011


I will try tomorrow to get the Marvel Mystery Oil.


__________________________________________________
BMW K100 (K589)
    

5Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 11:53 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
Have you done a compression test?  A compression tester isn't expensive.  You might be able to rent one at one of the auto parts stores.

Remove all the spark plugs, and spin the starter for 5-6 compression strokes on each cylinder while holding the throttle wide open.  Check the reading.  Normal is somewhere between 120 and 150 psi.

https://www.youtube.com/watch?v=cy5ffhgfyHI

https://www.youtube.com/watch?v=DerHlx-bO0s


__________________________________________________
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
    

6Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 1:25 pm

Laitch

Laitch
Life time member
Life time member
@Ccanov wrote:. . . after the stop I adjust the airflow meter bypass screw to set it to what I thought was the default value (close and then 2 full turns out) and same thing with the idle speed adjusting screw in the throttle body (one in the middle). I don’t know the default for this one...
You've replaced all the usual suspects that could affect performance and assert you've inspected and clean the grounds but now you're doing a tuneup backwards instead of in the correct order.

On a neglected relic like yours, you should first check and adjust valve clearances, then you should get a manometer and balance the throttle bodies. After that you can quit fooling around with that air volume screw on the air flow meter and adjust it correctly either by using the lean-drop method or an exhaust gas analyzer. Then you can adjust the throttle position switch. Instructions abound here. Start with this thread. There are also instructions in the BMW shop manual downloadable from the Tech Page in this site's Portal.

You should be able to borrow all the necessary tools using only a deposit at NAPA, AutoZone or another of the larger auto parts stores.

Are you burning fresh gasoline in that thing?


__________________________________________________
1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

7Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 5:38 pm

Ccanov

Ccanov
active member
active member
I guess that I am missing something, but I was ready to do the compression test (4 spark plugs out, not connected to the wire) and I cannot press the starter button.

For some reason was in 3th gear... 😬

    

8Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 6:10 pm

Ccanov

Ccanov
active member
active member
Test done, the battery died on the 4th one, the starter keeps trying with the ignition off... scary moment but all good... battery is charging now and I have to repeat the test!

And regarding the gasoline, I just get fresh gasoline to be sure, PO told me that was new, but it’s an easy replacement, so I will empty the tank and add the new one, with the Marvell oil.


I get 90psi on first 3, 95-100 on the 4th but... I forgot to open the throttle, so I guess that I need to repeat it to get the right number. Also the engine was cold because I cannot start it again.

Not sure if I will have time today to start measuring the valves clearance. So my next steps are:
Compression test again & check valves clearance. Once I have the numbers I’ll let you know.

The throttle bodies parts scare me a little... but I’ll try to find the tool to do it as next next step.

    

9Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 7:23 pm

Ccanov

Ccanov
active member
active member
@Laitch wrote:
@Ccanov wrote:. . . after the stop I adjust the airflow meter bypass screw to set it to what I thought was the default value (close and then 2 full turns out) and same thing with the idle speed adjusting screw in the throttle body (one in the middle). I don’t know the default for this one...
You've replaced all the usual suspects that could affect performance and assert you've inspected and clean the grounds but now you're doing a tuneup backwards instead of in the correct order.

On a neglected relic like yours, you should first check and adjust valve clearances, then you should get a manometer and balance the throttle bodies. After that you can quit fooling around with that air volume screw on the air flow meter and adjust it correctly either by using the lean-drop method or an exhaust gas analyzer. Then you can adjust the throttle position switch. Instructions abound here. Start with this thread. There are also instructions in the BMW shop manual downloadable from the Tech Page in this site's Portal.

You should be able to borrow all the necessary tools using only a deposit at NAPA, AutoZone or another of the larger auto parts stores.

Are you burning fresh gasoline in that thing?

@Laitch I clean the grounds, but measuring from ground to pin 13, reads 0.4ohms instead of 0. Not sure if there is something else or I should "re-clean or clean better"


__________________________________________________
BMW K100 (K589)
    

10Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 8:59 pm

Ccanov

Ccanov
active member
active member
Last update, I did the compression test, this time with the throttle fully open and all of them have the same reading: 165psi. I guess that it’s good based on the Hayes manual. My next question is... do I have to check the valves clearance now? Or should be good? Sorry but I know almost nothing about mechanical and I am trying to learn/read/understand as much as possible but I am not there yet Smile

Hopefully I’ll have some time tomorrow or Sunday to get all the gasoline of the tank and put the new one.

Thanks!


__________________________________________________
BMW K100 (K589)
    

11Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 9:25 pm

Laitch

Laitch
Life time member
Life time member
@Ccanov wrote:... do I have to check the valves clearance now?
Yes.


__________________________________________________
1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

12Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 10:24 pm

robmack

robmack
Life time member
Life time member
@Ccanov wrote:@Laitch I clean the grounds, but measuring from ground to pin 13, reads 0.4ohms instead of 0. Not sure if there is something else or I should "re-clean or clean better"
You have to account for the resistance of the wire linking Pin 13 of the ECU to the ground point. That could account for the 0.4 Ohm reading. If you have cleaned the grounding points to the frame and to the negative of the battery, you can rest assured that much of the gremlins introduced by corrosion have been addressed.


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

13Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 07, 2021 10:54 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
At 165psi on all cylinders, the rings look to be in good shape.  At this point I would say the Marvel Mystery Oil is optional and probably won't improve anything. 

Make very sure the battery is fully charged and cranking the engine without the voltage dropping too much.   Low system voltage can make the engine hard to fire.


__________________________________________________
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
    

14Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 08, 2021 9:49 am

DadofHedgehog

DadofHedgehog
Silver member
Silver member
@Ccanov wrote:Test done,

Not sure if I will have time today to start measuring the valves clearance. So my next steps are:
Compression test again & check valves clearance. Once I have the numbers I’ll let you know.

The throttle bodies parts scare me a little... but I’ll try to find the tool to do it as next next step.

I have a good K bike valve-setting tool and also a throttle body balancer tool. Pls see my PM back to you, neighbor ;-)


__________________________________________________
PRESENT:
1995 K75T.  I am the 3d owner.  Bought it in June 2019 with 6,242 miles on the odo.
1991 K100RS 4-valve attached to a 1990 Flexit sidecar. I am at least the 3d owner. Bought with 21,00+ miles on bike's odo.

PAST:
old (indeterminate age) Ural + sidecar
1997 Buell S3T Thunderbolt
1982 BMW R100CS
1974 Kawasaki KZ400
1970 Suzuki Titan
    

15Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 08, 2021 7:16 pm

Ccanov

Ccanov
active member
active member
@DadofHedgehog wrote:
@Ccanov wrote:Test done,

Not sure if I will have time today to start measuring the valves clearance. So my next steps are:
Compression test again & check valves clearance. Once I have the numbers I’ll let you know.

The throttle bodies parts scare me a little... but I’ll try to find the tool to do it as next next step.

I have a good K bike valve-setting tool and also a throttle body balancer tool.  Pls see my PM back to you, neighbor ;-)

PM Sent, thank you!!


__________________________________________________
BMW K100 (K589)
    

16Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sat Jan 09, 2021 12:26 pm

cycleman

cycleman
Silver member
Silver member
In your first video it didn't look like the choke/enrichner was on. These bikes are a bit cold blooded at startup and they do like their choke. You can ride away with it on and within a couple of blocks shut it off. The engine needs the slightly faster idle ( that's all the choke does on these bikes ) at startup until the ECU/FI computer starts to get a signal from the water temperature/air sensor. Once it reaches a certain temp the computers take over the mixture and you don't need the choke. The engine sounded exactly like a cold engine without choke.

I'm not aware of any reason to adjust the air flow meter, unless it was causing the problem. The top of the airbox has to be connected to the intake. If it isn't the system can't measure the air flow or the air temp and provide the right information to the ECU/FI. I really don't think you had anything wrong at the start other than a low battery & no choke. You can't make any adjustments to throttle bodies etc until the engine is fully warmed up and the fan cycles on and off.

I would suggest that you get everything back to stock settings, change out the fuel injectors ( either reconditioned or new or get yours professionally cleaned ). No engine likes to sit and as you ride it more it will run better and better. A cardinal rule of thumb when you start troubleshooting, is only do one thing at a time, check if that doesn't cure the problem, then leave that one alone and go onto the next one. When you make multiple changes you end up getting lost.

The KISS principle works well in these situations and a lot of the time it is something minor, like a bad connection for example causing the problem. Do the simple stuff first and move on to the more complex.

    

17Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sat Jan 09, 2021 1:47 pm

Ccanov

Ccanov
active member
active member
Zzz cycleman wrote:In your first video it didn't look like the choke/enrichner was on. These bikes are a bit cold blooded at startup and they do like their choke. You can ride away with it on and within a couple of blocks shut it off. The engine needs the slightly faster idle ( that's all the choke does on these bikes ) at startup until the ECU/FI computer starts to get a signal from the water temperature/air sensor. Once it reaches a certain temp the computers take over the mixture and you don't need the choke. The engine sounded exactly like a cold engine without choke.

I'm not aware of any reason to adjust the air flow meter, unless it was causing the problem. The top of the airbox has to be connected to the intake. If it isn't the system can't measure the air flow or the air temp and provide the right information to the ECU/FI. I really don't think you had anything wrong at the start other than a low battery & no choke. You can't make any adjustments to throttle bodies etc until the engine is fully warmed up and the fan cycles on and off.

I would suggest that you get everything back to stock settings, change out the fuel injectors ( either reconditioned or new or get yours professionally cleaned ). No engine likes to sit and as you ride it more it will run better and better. A cardinal rule of thumb when you start troubleshooting, is only do one thing at a time, check if that doesn't cure the problem, then leave that one alone and go onto the next one. When you make multiple changes you end up getting lost.

The KISS principle works well in these situations and a lot of the time it is something minor, like a bad connection for example causing the problem. Do the simple stuff first and move on to the more complex.
When I try to use the choke it’s usually worst. Also I reas that there are two choke positions but I just have 1 click. 

I try to adjust the screw because the previous owner mess with them I try to set them to spec. I’ll try with my other motorcycle battery just to be 100 sure that the battery is holding together after all the starts and no run (I charge it but now I am not 100% sure if that may be affecting) 

I’ll try to check the valves clearance today. I want to be sure that is a good working bike before start to removing parts and building something with the k. Also I need to make it work to register it and pass the va inspection..


__________________________________________________
BMW K100 (K589)
    

18Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sat Jan 09, 2021 2:43 pm

robmack

robmack
Life time member
Life time member
@Ccanov wrote:I try to adjust the screw because the previous owner mess with them I try to set them to spec.
So, which screw(s) is it you are adjusting?  You used the plural "them" which implies multiple.

Starting problems on a 87 K100  Thrott10

Is it the main throttle adjustment screw (#2 in the diagram)? The brass coloured idle adjustment screws (#1 in the diagram)?  The interlink screws with blue locktite on them (not illustrated)?  Don't get too hung up on the diagram because it is showing K75 TBs and you have a K100.

You adjust the idle using the idle adjustment screws and not the main throttle adjustment.  The butterflies should naturally close shut nearly blocking off all airflow in the TB throat, and then set the main throttle adjustment screw to contact the TB frame.  It acts as a stop.  Each idle adjustment screw has a factory starting point of about 1-1/2 turns out.  You use a vacuum gauge to balance the TBs and set the idle.  There are numerous posts on this forum that describe the procedure. You must never touch the interlink screws ever.  If they have been touched, then it's going to be a chore to reset them.


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

19Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sat Jan 09, 2021 7:20 pm

Ccanov

Ccanov
active member
active member
I mean the #2 at the throttle body. I was talking in plural because of the other screw in the AFM.


__________________________________________________
BMW K100 (K589)
    

20Back to top Go down   Starting problems on a 87 K100  Empty K100 Wont start Sun Jan 10, 2021 10:46 am

Kr4mo

Kr4mo
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active member
I'm surprised no one has suggested testing the fuel pressure going to the rail.  Found a split hose in the tank of a K100 recently.

    

21Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sun Jan 10, 2021 11:21 am

glennpm

glennpm
Silver member
Silver member
Hi,

I noticed that you didn't mention checking ICU terminal values. Just a heads up on the ICU checks, the terminal marking for the "female" connector are actually male numbers.

Starting problems on a 87 K100  Profile_mask2


Glenn

Starting problems on a 87 K100  Cleardot10:03 AM (4 minutes ago)





to me
Starting problems on a 87 K100  Cleardot


-------- Forwarded Message --------
Subject:        Feedback on your K100 trouble shooting guide
Date:   Mon, 26 Feb 2018 14:59:49 -0500
From:   Glenn <glennpm@gmail.com>
To:     k100beemer@gmail.com



"Hi Bertrand,

Great work on your guide! I snagged a copy a few years back and now have
need of it since my bike is not starting well at all.

In the process of going through the diagnostics I found an error in your
"Electronic Ignition Module Test" diagram. The pin numbers shown are for
the male module terminals and not for the female plugs.I found this
since I had no continuity at ground and first thought I found the issue
but further investigation lead me to pull the female plug rubber boot
back and found that wire in back of what you labeled as #8 is brown and
the ground connection of #1. Please see the attached.

Best regards,
Glenn"

Attachments areaStarting problems on a 87 K100  Igniti10
Starting problems on a 87 K100  Img_1210
Starting problems on a 87 K100  Img_1211

    

22Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sun Jan 10, 2021 1:16 pm

Ccanov

Ccanov
active member
active member
I was yesterday with our colleague from the forum and check with the carbtune, all seems good there but we notice that with the carbtuner plugged it was able to keep the idle so I am going to replace the vacuum caps and tube. Easy test. I remember to test the ICU and looks good but I did not take note of the results. I will do it again. I also test the injector out of the rail with an external battery but I did not test them connected to the motorcycle so I think that is something that I should look at just tu ensure that are spraying gas to the engine. Other than that all the fuel lines, fuel pump, filter and fpr was changed so I will check again that all the hoses clamps are tight. Then I will check the  intakes rubber to look for any air leak.

My next steps:
- replace vacum caps and the line from the 1st to the fpr
- check intake “rubber” (the one in the middle)
- remove gas and check the fuel tank lines clamps
- test icu and write down the results. 
- clean again earths and connector (now that the tank is off)
- measure valve clearance (I did not have a torque wrench so I am waiting to receive it to ensure that I bolt the screws to the spec once I measure them.

We suspect that is something related with air leak (or blocked) or fuel in the injectors, with the starter spray “works at idle” but the moment we apply throttle or choke died. 

I will update the first post with the results and tests done so far so we have everything in there.


__________________________________________________
BMW K100 (K589)
    

23Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sun Jan 10, 2021 8:54 pm

Ccanov

Ccanov
active member
active member
Small update on the tasks for today (I’ll update the first post latter with all the data)

- new vacuum caps and vacum line to the FPR = same result 
- the injectors are sorting fuel with attached to the rail and harness when I press the start button (I guess this clear the fuel issues)
- rubbers between the throttle body and box, some of them are broken (ordering new ones and cleaning the box and throttle body as next task) 
Starting problems on a 87 K100  Ec079710

- I was checking the icu conector but the first pin (ground) was not giving continuity to the negative of the battery. From the pin to the conector in the middle in the wiring harness I have continuity, but after it joins the harness I lost track of it. The weird thing is that it fires up and keep idle “sometimes”... I was following the crazy frog troubleshooting connector schema but now I think that the image at this post it’s different so I will need to check again the conector pins because I think that I did it wrong Sad 

When I was there I realized of one of the wires (I think that goes to the hall sensor conector from the harness) with this aspect (not sure it that need to be replaced or it’s like that..) 
Starting problems on a 87 K100  29a3a310

So in the meantime that the rubbers arrive I will be cleaning the connectors, the box above the throttle body and the throttle body itself (once I read how to disconnect the choke) and charge the battery Smile

Thanks to all for your time reading and answering this. I hope to get to get it fixed with your help and I am learning a lot with all this.


__________________________________________________
BMW K100 (K589)
    

24Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Sun Jan 10, 2021 9:06 pm

glennpm

glennpm
Silver member
Silver member
Regarding checks of ICU, see my post above at 12:15PM.
The drawing in Bert’s guide is not correct.

    

25Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Mon Jan 11, 2021 10:21 pm

Ccanov

Ccanov
active member
active member
@glennpm wrote:Regarding checks of ICU, see my post above at 12:15PM.
The drawing in Bert’s guide is not correct.
Yes, that is what I realized when I come back home.


__________________________________________________
BMW K100 (K589)
    

26Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Tue Jan 12, 2021 8:40 pm

Ccanov

Ccanov
active member
active member
Quick update... tomorrow the parts will arrive so hopefully I have time to mount them (rubbers between the throttle body and plenum or air box)

I try to measure today the valve clearance... what a mess 😂 in all the videos I saw there wasn’t that much oil in there, but also... they move it like nothing and I was not able to move it with the 19mm. I need to check again how to do it because I did not want to put too much pressure in there. But on YouTube move the crankshaft looks pretty easy 😂


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BMW K100 (K589)
    

27Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Tue Jan 12, 2021 8:44 pm

robmack

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Remove the spark plugs so there is no compression.  It should take some effort to turn with the wrench-method but not a lot.


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

28Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Tue Jan 12, 2021 8:51 pm

Ccanov

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@robmack wrote:Remove the spark plugs so there is no compression.  It should take some effort to turn with the wrench-method but not a lot.
😂 thanks! I just realized that when seen the video from Chris xxx I completely forgot about that.


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29Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Wed Jan 13, 2021 10:13 pm

Ccanov

Ccanov
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One more update with the last tests done. 

- I measure the valves clearance and all of them are within the spec. The #intake was at 0.006 inch (at the minimum) but in all of them I was able to check the minimum. The video said if they are loose leave them *** alone, so I just Che k that the minimum was ok.  And it is.

- I replace the rubber between the throttle body and the black box, clamps and now it should be good. I did not replace the one below the throttle body but I put some starter fluid in there and i do not notice anything. So I guess they are ok. I think that it smells more now to gas than before while trying to start it, not sure if that give you any idea.

Same result. It’s hard to start it, but I was able today to keep it idling for 20 seconds and after that no more starting... 

Next step... replace the injectors and measure the fuel pressure. Our colleague from Arlington lend me 4 injectors and I will test with them. 

After that I guess that I will get back to the trouble shooting guide and start checking again. 

I read a similar case and the issue was with the spark plugs wire, what is the expected resistance for them?


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30Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 14, 2021 12:06 am

Laitch

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@Ccanov wrote:I read a similar case and the issue was with the spark plugs wire, what is the expected resistance for them?
My source indicates 5KΩ in the spark plug cap and 1KΩ in the coil plug in the OEM K100 2V wires.


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1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

31Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 14, 2021 9:38 pm

Ccanov

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So, today I went back to double check with the multimeter. I did not want to mess again with the gas tank, so that is for tomorrow/weekend.. 

I check the resistance in the spark plug wires and all of them where 5.xx k ohms, so that it’s something that it’s ok.

The other thing that I check was the LE-Jetronic conector (female) just to double check that o get the readings from the AFM, and with the tank plug off, all the values look the same than testing the AFM at home. But I found something (or maybe not...) the pin 4 (starter running) should have a reading of 12v, but I get 8.8v with the multimeter ground at battery and pin 4. The battery was 12.78v and I also check with another motorcycle battery (wich starts perfect and I use frequently) and have the same reading. 
Pin 12 (ground to injectors) I measure them with the pin 12 and 9 and get 4ohms (I guess that is ok because I have 4 injectors?) 

Apart from that everything all the pins give the expected value. 

Any idea on why u am getting the 8.8v from pin 4?


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32Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Thu Jan 14, 2021 9:48 pm

robmack

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When you are starting the bike, is the gearbox in neutral or are you pulling in on the clutch?

The only places where you can possibly loose voltage are the start switch and/or the clutch switch and/or the 9-pin connector under the tank.  Poor contact on any or all of these points in the circuit is giving you a 3.4V drop.  You might want to examine and  clean the switch and connector contacts if you haven't already done so.  That includes the 9-pin AMP connector under the tank and the connector to the clutch switch.  Make sure there is good contact between pins.

What voltage do you read between Pin 6 (Black/green) on the 9-pin connector under the tank and ground with the bike in gear and the clutch pulled in? How about in neutral?

Play around and see if you get a different reading on Pin 4 of the ECU if you pull in the clutch in gear rather than start in neutral.


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

33Back to top Go down   Starting problems on a 87 K100  Empty No go Thu Jan 14, 2021 10:14 pm

daveyson

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I've only read the last few posts, I'll try to get to more later.

8.8 sounds a bit low, but while cranking the Voltage should drop I think because the starter is turning and it's driving the engine, so that's pretty hard work. Maybe check the Voltage drop across the battery while cranking.

I have a deep respect for Chris Harris, but I prefer the workshop manual with valve clearances. The clearance should not be greater than the maximum clearance, I recon.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

34Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 12:16 am

Laitch

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Like daveyson indicated, the battery might be faulty. It's already been discharged once during this exploration and if that has happened several times since it has been installed, it might have damaged cells.


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1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

35Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 1:35 am

Ccanov

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@Laitch wrote:Like daveyson indicated, the battery might be faulty. It's already been discharged once during this exploration and if that has happened several times since it has been installed, it might have damaged cells.
I tried with 2 batteries, once that I am using with the k100 for testing and charges at night, and the other one the one that is currently on my other motorcycle, which is good and works fine.

What I do not understand is if I am loosing power in the way, and who is taking it... with the starter depresses the battery shows 12.7x but the pin in the connector says 8.8v. should be there 12v too? I can buy another battery to check but I am pretty sure that the one in the other motorcycle is completely fine. 

Thanks!


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36Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 2:46 am

Laitch

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@Ccanov wrote:Any idea on why u am getting the 8.8v from pin 4?
I can buy another battery to check ...
Don't buy another battery if the battery you're using can hold a charge.

Why 8.8V? I read this chart in the BMW Diagnose manual as indicating 8.8V from terminal 4 of the Fuel Injection Control Unit is ok. ≈ 8V means ≤ 15% greater than 8V. Your reading is approximately 10% greater. 

Starting problems on a 87 K100  Scree121


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1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

37Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 12:33 pm

Ccanov

Ccanov
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 Laitch wrote:
@Ccanov wrote:Any idea on why u am getting the 8.8v from pin 4?
I can buy another battery to check ...
Don't buy another battery if the battery you're using can hold a charge.

Why 8.8V? I read this chart in the BMW Diagnose manual as indicating 8.8V from terminal 4 of the Fuel Injection Control Unit is ok. ≈ 8V means ≤ 15% greater than 8V. Your reading is approximately 10% greater. 

Starting problems on a 87 K100  Scree121

I saw in the troubleshooting guide that 12v was the expected value. I guess that 8.8 is ok

I post and image of one of the wires that goes to the icu (under the tank) female conector, I think is the one that goes to the hall sensor connector, which is in bad shape, but I do not know it is like that and I am just seeing weird things where I should not. 

Can any one confirm if yours look like that? I guess that I should replace it but.. I prefer to double check first.. 

Here is a crop of the previous image. 

Starting problems on a 87 K100  Fa35b010


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38Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 1:33 pm

Laitch

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@Ccanov wrote:I guess that 8.8 is ok . . .
I guess that I should replace it but. . .
I post and image of one of the wires that goes to the icu (under the tank) female conector, I think is the one that goes to the hall sensor connector, which is in bad shape . . . Can any one confirm if yours look like that?
Rely on data and observation. Accurate guessing takes experience; having understanding is better.

In reference to the Hall sensor connector, what does in bad shape mean and what do you intend to do about it?

I haven't seen Ramen noodles used in wiring until your photo but I haven't delved as deeply as you, apparently. I might take a look at mine while it's in hibernation, but I tend to let sleeping dogs lie.


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1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

39Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 1:58 pm

Ccanov

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@Laitch wrote:
@Ccanov wrote:I guess that 8.8 is ok . . .
I guess that I should replace it but. . .
I post and image of one of the wires that goes to the icu (under the tank) female conector, I think is the one that goes to the hall sensor connector, which is in bad shape . . . Can any one confirm if yours look like that?
Rely on data and observation. Accurate guessing takes experience; having understanding is better.

In reference to the Hall sensor connector, what does in bad shape mean and what do you intend to do about it?

I haven't seen Ramen noodles used in wiring until your photo but I haven't delved as deeply as you, apparently. I might take a look at mine while it's in hibernation, but I tend to let sleeping dogs lie.
I mean that I was not expecting to see the internal metallic threads of the wire, just the plastic cover to the pin. So I am not sure if someone pull that part and may be interfering with the reading from the hall sensor. 

By fixing it I think that I should replace that wire from the hall sensor conector in the wiring harness to the icu connector. I will check the pins in the icu and check for continuity between that pin from icu connector to the hall sensor conector. My main concern here is that it may be intermittent due to the wire status.


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40Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 3:19 pm

Dai

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DON'T touch! The braiding is a screen; it connects to earth in the main loom and floats free down in the HES box. It that's the plug off (on?) the main loom then they all look like that.

Just checked the original pic - it's where the wires go into the ICU module. Yep - they ALL look like that! 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
    

41Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 3:41 pm

robmack

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@Ccanov wrote:What I do not understand is if I am loosing power in the way, and who is taking it...
There are many opportunities for power to be lost in a circuit.  Some are visible and others are hidden.

In your "starter engaged" circuit being discussed here, resistance is offered by several elements - the internal resistance of the battery, the resistance of the wiring, the resistance of corrosion on connections such as ground connections and power connectors, resistance of the ICU circuits, and resistance of switches such as the starter switch.

When you press the start switch, you complete the circuit and current starts to flow.  Each of the above named elements impedes that flow and causes power loss which is exhibitedl as loss in voltage as each element steals a bit of the power from the circuit.  If you were able to measure all of these voltage drops individually and then add them all up, the sum would be the battery terminal voltage.  When you measure one element - pin 4 the ICU -- you're measuring a voltage drop close to the end of the circuit.  So, all the lost power is occurring upstream of that load, appearing as voltage across the start switch, across the wires, across the internal batter resistance, across the fuse, across and the power connectors.  

Because the internal resistance on a battery increases with age, an old tired battery will drop a significant amount of voltage across that internal resistance once current starts to flow and only then.  That's why you can measure the open terminal voltage of a battery as very high yet watch that terminal voltage drop like a stone once a load is placed on the battery.


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

42Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 4:03 pm

Ccanov

Ccanov
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Ok ok, don’t touch! Smile 

So based on the answers the 8.8v it’s ok, and the wire it’s ok too, so I will stick to the pending things discussed here, as all of them requiere to “play” with the gas tank I’ll do everything together.

- check ICU pins values.
- check fuel pressure
- replace the injectors


I’ll update as soon as I get it done.


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43Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 5:39 pm

Ccanov

Ccanov
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@glennpm wrote:Hi,

I noticed that you didn't mention checking ICU terminal values. Just a heads up on the ICU checks, the terminal marking for the "female" connector are actually male numbers.

Starting problems on a 87 K100  Profile_mask2






Glenn  





Starting problems on a 87 K100  Cleardot10:03 AM (4 minutes ago)











to me
Starting problems on a 87 K100  Cleardot


-------- Forwarded Message --------
Subject:        Feedback on your K100 trouble shooting guide
Date:   Mon, 26 Feb 2018 14:59:49 -0500
From:   Glenn <glennpm@gmail.com>
To:     k100beemer@gmail.com



"Hi Bertrand,

Great work on your guide! I snagged a copy a few years back and now have
need of it since my bike is not starting well at all.

In the process of going through the diagnostics I found an error in your
"Electronic Ignition Module Test" diagram. The pin numbers shown are for
the male module terminals and not for the female plugs.I found this
since I had no continuity at ground and first thought I found the issue
but further investigation lead me to pull the female plug rubber boot
back and found that wire in back of what you labeled as #8 is brown and
the ground connection of #1. Please see the attached.

Best regards,
Glenn"

Attachments areaStarting problems on a 87 K100  Igniti10
Starting problems on a 87 K100  Img_1210
Starting problems on a 87 K100  Img_1211

It was quick, just 2 pins... and stop testing. I’ll test the other ones later, but so far there is something that I did wrong or I do not have power to sensor.. I place the multimeter in 20v, red to the pin 2, black to ground (at battery)

🤔 pin 1 ok. Pin 2 gave a reading of 0v but should be 12v. I try with ignition on and off. But as far as I understood, if that relay is not working the pump and more components are not getting power, and I already test the pump and see the injectors spraying fuel.


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44Back to top Go down   Starting problems on a 87 K100  Empty No go Fri Jan 15, 2021 7:00 pm

daveyson

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Do you have power to the pin from the kill switch, with the ignition on? (don't have my books with me)

Pin 1 is earth.

With the ICU unplugged you will have 0V at pin 2 because it's a power output.

I think the image as well as the numbers need to be mirrored in the above pic. Ignore the pic and look at the table to find out which pin is which (pin 2 is to the hall sensors,  not the fuel relay)  

Maybe give the plugs a good look and clean.

Pin 10 (from kill switch) is a power input with ignition on. Pin 6 is a power input while cranking from the start button.

No power at 10 could explain why you lose power when releasing the start button.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

45Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 8:55 pm

Dai

Dai
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Pin numbers are on the back of the plug. Well, 1, 8, 9 and 15 are anyway! 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
    

46Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 9:11 pm

Ccanov

Ccanov
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I’ll check again the PIN 2 and also, with the ICU connected I can check if I have 12v in the connector for the hall sensor (red wire) based on the wiring diagram if I am not wrong. 

If I do not have 12v in the hall sensor connector at the wiring harness (is the ignition trigger assembly, Right?) may explain why is not starting. 

Starting problems on a 87 K100  04cf0b10


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47Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 9:26 pm

Laitch

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Then there's this.

Starting problems on a 87 K100  Hall_t10


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1995 K75 81,000 miles
Starting problems on a 87 K100  Usa-lo10
    

48Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 9:52 pm

Ccanov

Ccanov
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Ups! I test the hall sensor conector and get the 12v for the red and 5.03v for the sensor. So I was confused about how can I get the volts there and not in the conector... 

Then I realized that the conector was connected to the icu, measure again the pin 2 and I get the 11.36v... So, to check the pins for the ICU, the connector have to connected right? 

Sorry for this dumb question but I really thought that was like testing the other conector 😬 

I’ll continue checking the other pins tomorrow, that pin 2 thing was getting my sick, so I went down to test it one more time, but I did not have the other measurements for the other pins.


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49Back to top Go down   Starting problems on a 87 K100  Empty Re: Starting problems on a 87 K100 Fri Jan 15, 2021 9:56 pm

Ccanov

Ccanov
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@Laitch wrote:Then there's this.

Starting problems on a 87 K100  Hall_t10
Which book has that info?


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50Back to top Go down   Starting problems on a 87 K100  Empty No go Fri Jan 15, 2021 10:03 pm

daveyson

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You're right, the ignition trigger assembly is another term for hall sensors. I wouldn't mess with them,  see all the warnings about that in Bert's guide.

I think its safer to check for power at pin 10 with the ignition on and the ICU unplugged.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

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