Post by: mophead on March 26, 2018, 11:59:09 AM
Have an issue that has occurred lately. Had a battery that I replaced couple of weeks ago. Got out one day and bike would not start. Started fine at home but not at a stop. Pushed and popped clutch and made it home fine. Bought new battery next day and installed. Took bike out four days later and bike was running well except thought I felt a little surge at steady throttle. It started getting worse so I u turned back home. Figured it was fuel filter. Changed it our for new and still surges. Had an extra fuel pump that came with the bike so changed that and still surges.
Bike idles fine but if you get on it hard you can feel the surge. Surge mainly occurs at steady throttle. If on or off I don't feel it.
If I let it sit overnight it is now hard to start like it is getting no fuel. Once I coax it to start it starts fine on first bump after that. Replaced spark plugs and that did not help. Old one looked fine except they were some double electrode Bosch plugs. I'm leaning toward the fuel pressure regulator being suspect or perhaps a line going to or from it.
Have searched several threads and not really seen anything about surging and a fix. I did do the propane test around the rubber at injectors and intake rubber bushings and did not see any increase in engine speed.
Had the bike out for several runs of 200 or more miles before changing the battery and it ran just fine. No surge or rough running at all. Just ran like a good K bike should.
Fuel pressure regulator and new battery doesn't make much sense but perhaps the collective wisdom here has had this pop up before. Any suggestions appreciated.
Post by: Chaos on March 26, 2018, 12:33:26 PM
Post by: mophead on March 26, 2018, 01:04:54 PM
Post by: The Mighty Gryphon on March 26, 2018, 01:21:47 PM
How is your throttle position switch set? It's a long shot, but if it's set to trip at the throttle setting for cruising speed it could be shutting off the fuel momentarily at engine speeds above 3000rpm.
Post by: The Mighty Gryphon on March 26, 2018, 04:41:34 PM
Post by: Martin on March 26, 2018, 05:06:25 PM
Regards Martin.
Post by: bizzaro on March 27, 2018, 09:13:56 PM
Its not water as I had run it down to almost empty on last ride before this started. :dunno2:
So when you say surge, do you actually mean cutting out or stumbling? That's what I thought. And this happened right after running the tank almost dry? Maybe you have sucked any possible crap that was in the tank into your lines? I would start by purging your fuel lines as much as you can by disassembling them at all connections and try and run some fuel through them. IE: At the fuel rail, disconnect the hose, stick in a bucket and turn on the key to to turn on the fuel pump and run some gas through it. Then move on to the fuel rail and disconnect the line to the FPR. Where you can, hook it up in reverse to back flow. Do this at all your connections right on up the line. Remember the fuel will/may be under pressure when you are disconnecting them, make sure you have eye protection and something to to catch spray(rag), and (bucket) to catch the fuel. Just by draining and back draining you may get lucky and clear them out. I think you got some crap in there. And it is lodged somewhere in your fuel system and causing your "stumbling"! Just a hunch?. :popcorm
Post by: mophead on March 31, 2018, 01:50:26 PM
I have taken all the fuel lines off and flushed them. Put a pressure gauge on the fuel rail where it goes back to the tank and get a steady 38 psi when it is running.
Have cleaned the Motronic plug three different times. Cleaned the four wire plug twice. Replaced spark plugs and air filter. Replaced the fuel pump and the fuel filter.
I can't believe changing a battery and getting low fuel light can destroy what was a sweet running bike. At this moment in time I would be up for taking it outside my shop and set the sumbitch on fire and watch it burn. Count it up to just one more money mistake made in my life.
Sorry for the rant and appreciate all the help given but this thing is really pissing me off.
Post by: The Mighty Gryphon on March 31, 2018, 02:27:21 PM
Knowing now that you have a Motronic system on your bike I wonder if you have done any checks for fault codes that the Motronic may have stored. Have you seen this article:
http://hrsbstaff.ednet.ns.ca/bvogel/K100/download/Motronic%20Fault%20Codes.pdf
The procedure for setting the throttle position sensor(TPS) is pretty nice. It really makes setting it easy.
Post by: mophead on April 06, 2018, 08:58:20 PM
When I hook up the connections to test the Motronic all I get is 3333 fan test. It doesn't give any other codes. Turned off the ignition and restart the test and get 3333 every time.
When testing for the TPS I assume it has to be connected. How do you connect to pin 1 and 4 if the TPS plug is connected to the TPS? I unhooked the connector plug and turned ignition on, connect voltmeter to pin 1 and 4 and get .002 on the voltmeter but that takes the TPS out of the loop. Do you have to take the rubber boot off the connector to check pin 1 and 4 while it is hooked up to the TPS?
Post by: The Mighty Gryphon on April 06, 2018, 10:40:07 PM
To test the TPS: With the Ignition OFF, Ground Pin #3 on the test connector. Turn on the ignition. Open and close the throttle. You should be able to watch the temperature warning lamp on the tachometer blink ON at idle and OFF just above idle.
To adjust the TPS: With the throttle closed, loosen the TPS screws and adjust it so the lamp is just coming on. Of course, you are going to do this with pin #3 connected to ground and the ignition ON.
There is no need to connect to the TPS.
Post by: bizzaro on April 07, 2018, 07:06:17 AM
http://www.motobrick.com/index.php?topic=1521.0 (http://www.motobrick.com/index.php?topic=1521.0)
Redundant post! Oh well! That'll happen! :popcorm
Post by: mophead on April 07, 2018, 01:31:47 PM
TPS light on at idle, goes off just off idle just like the test says it should.
As I read this the Motronic test should have shown 1215 TPS out of range. It did not. Every time I hook the number one pin on the connector all I get is 3333 fan test. Turn it off, ignition back on, ground for 5 seconds, then 3333 code with fan coming on and off during the test. I get nothing but 3333 when testing Motronic. Have not got 4444 or any other code at any time.
Is there a different way to pull Motronic codes that I am doing wrong? Did I fry the thing changing the battery?
Bike still will not start. Plugs are getting gas. They're wet.
Post by: bizzaro on April 07, 2018, 02:30:01 PM
Post by: mophead on April 07, 2018, 03:15:34 PM
Checking TPS via voltmeter and number 1 pin on test connector I get 2.86 volts at idle. Test says it should be zero volts. Off idle I get 12.25 volts which as I read it should be fine.
Hook up number one pin to check motronic codes all I get is 3333 fan test with fan on and off intermittently. Is that the default for checking motronic codes? Never have got anything but 3333 fan test. Turn off ignition to clear to next fault and returns to 3333 each time.
That doesn't seem right.
Post by: bizzaro on April 07, 2018, 05:22:52 PM
And pretty sure you need analog VM. I assume you have the directions handy? Notice you have to ground it a second time, then remove the 2nd ground after about 5 seconds? But really I don't think the codes are gonna help ya. But who knows. Have you tried to balance the throttle bodies? Also ignition switches are suspect in these instances. It is easy to buy pass the ignition to check it? :dunno
Post by: Laitch on April 07, 2018, 05:32:31 PM
Turn off ignition to clear to next fault and returns to 3333 each time.Here (http://www.largiader.com/articles/motronic.html), under the heading Motronic Codes, Anton Largiader mentions pulling fuse#5 for a few seconds to clear the fault codes
That doesn't seem right.
Post by: bizzaro on April 07, 2018, 05:42:18 PM
Post by: johnny on April 07, 2018, 07:46:58 PM
everybody knows about fuse 5... its assumed you already pulled fuse 5... like its assumed you turned the key on and pressed the start button before you say it wont start... plus you are running the fan test over and over again... sounds to me its a mixture problem... too rich perhaps...
autumrideafterweedcookies.jpg (62.02 kB . 768x556 - viewed 819 times)j o
Post by: mophead on April 08, 2018, 02:20:27 PM
Turned off onto a side road and it started surging stumbling again. Went about 50 miles total and surging all the way home. When I finally get it started it smells like its running rich. Going to let it cool down and pull plugs to see what they look like.
I did try the motronic test after pulling fuse 5 last night and it immediately goes to fan test 3333.
Post by: bizzaro on April 08, 2018, 06:00:32 PM
Post by: mophead on April 08, 2018, 07:50:12 PM
Temp light and fan on/off are all going on at the same time.
Post by: bizzaro on April 08, 2018, 08:07:03 PM
Post by: mophead on April 08, 2018, 09:10:38 PM
Post by: mophead on April 08, 2018, 10:31:38 PM
Done for today.
Post by: mophead on April 09, 2018, 10:16:27 PM
Turned bike back toward home which gave me the 20 mph tailwind and bike started surging even more. Could get it to 110 but surging even more. Dropped back down to 70 mph and stumbled back home. Bike idles fine now so thinking after setting TPS to correct setting the computer learned and returned the idle to normal.
Ambient temperature was 68 degrees F. Could the temperature sensor be going bad making for a rich fuel mixture that causes the surging? Extra cooling going into the headwind ran fine and less cooling with the tailwind and rough running.
Post by: The Mighty Gryphon on April 09, 2018, 11:46:40 PM
It is beginning to sound to me like the problem could be related to a throttle setting. I believe the throttle position sensor for the Motronic system is a potentiometer with a wiper travelling over a resistance element, and as such could have a dead spot. Without knowing what is inside I can't suggest a test, but the idea would be to see if there is a smooth continuous change in resistance as the throttle is opened. With your problem, I would expect to see the resistance jump at the throttle position where the surging is occurring.
Slowly opening and closing the throttle with an analog meter connected to the TPS output should show if there is a noisy pot in the throttle position sensor. Can't say which pins on the sensor you need to connect to.
Post by: Laitch on April 10, 2018, 12:34:07 AM
I can't recall if there is a fault code for a bad temperature sensor.Old age does that. :giggles
Anyway, here's a post (http://www.k11og.org/forum/viewtopic.php?t=2110) with more Motronic codes, pin numbers and other relevant detritus which might help. The author indicates it applies to a '93 K11 but could apply to later models, too. ¿Quién sabe?
Post by: bizzaro on April 10, 2018, 05:50:50 AM
Post by: mophead on April 10, 2018, 02:02:20 PM
Gryph,
I like the idea you put forward. To answer your question it is not hard to start when warm. I'll do some research and see if there is any info on which pins to connect to. When I adjusted the TPS earlier I was just checking for the required voltage which was off by the way.
The bike has been very difficult to start through all this scenario. Since setting the TPS and riding it for a few miles it now has started right up on cold start where before it would not. What is strange when it did not want to start I would hit the starter time and time again and no start. Come back 30 minutes later and it would fire right up first bump of the starter.
Post by: rbm on April 10, 2018, 06:02:58 PM
Post by: The Mighty Gryphon on April 10, 2018, 07:55:55 PM
https://repairpal.com/throttle-position-sensor
If you need to replace it, here's a good one on eBay:
https://www.ebay.com/itm/BMW-R1100R-13631461852-Throttle-Body-Position-Switch-k1100rs-k1200gt-k1200lt/112370665060?hash=item1a29d04664:g:hpoAAOSwc-tY8Qcl&vxp=mtr
Post by: mophead on April 11, 2018, 10:32:39 AM
Info on TPS internals and troubleshooting Bosch Motronic on a K1100. (http://www.oocities.org/fwarner_au/mc_things/K_fuel_injection.html)
Thank you Robert!! Will be checking some of these resistance measurements later and maybe find the culprit.
Post by: mophead on April 11, 2018, 10:37:28 AM
Here's a list of some symptoms of a bad TPS:
https://repairpal.com/throttle-position-sensor (https://repairpal.com/throttle-position-sensor)
If you need to replace it, here's a good one on eBay:
https://www.ebay.com/itm/BMW-R1100R-13631461852-Throttle-Body-Position-Switch-k1100rs-k1200gt-k1200lt/112370665060?hash=item1a29d04664:g:hpoAAOSwc-tY8Qcl&vxp=mtr (https://www.ebay.com/itm/BMW-R1100R-13631461852-Throttle-Body-Position-Switch-k1100rs-k1200gt-k1200lt/112370665060?hash=item1a29d04664:g:hpoAAOSwc-tY8Qcl&vxp=mtr)
Thank you sir. Going to check out some of the measurements Robert's info suggests and might have to get on that TPS.
Post by: The Mighty Gryphon on April 11, 2018, 12:18:40 PM
Post by: mophead on April 11, 2018, 06:44:21 PM
Last two days bike has started easily. Now back to no start without grinding on starter then going back later to have it start. All I did was change the battery and the current one shows 13+ volts after recharging with battery tender. This thing is killing me.
I have searched for the meaning of 2343 code, mixture is at limit. Cannot find how to dial down the mixture assuming it means fuel mixture which I'm not sure that is what it means.
Post by: johnny on April 11, 2018, 08:13:18 PM
i dont know however im thinking it maybe (https://www.google.com/search?source=hp&ei=eqXOWqeEFIXctQWgnJP4BQ&q=bosch+15738+oxygen+sensor&oq=Bosch+15738&gs_l=psy-ab.1.1.0j0i22i30k1l2.2339.2339.0.4852.3.2.0.0.0.0.127.127.0j1.2.0....0...1.2.64.psy-ab..1.2.241.6..35i39k1.115.gHDEKuXqy_8) the o2 sensor (https://www.euromotoelectrics.com/BMW-Oxygen-Sensor-R1100-K-11-78-1-464-492-p/o2-492.htm) in the exhaust... id disconnect it and start it and see if it behaves the same...
if me... this next... (http://www.ibmwr.org/ktech/O2-sensor-testing.shtml) if that aints it id check to make sure all grounds are clean and tight at the battery and their terminations...
j o
Post by: mophead on April 11, 2018, 09:50:39 PM
Post by: mophead on April 23, 2018, 07:10:50 PM
Post by: mophead on May 08, 2018, 09:59:20 AM
It is with great reluctance that I post this. The Brick does not surge anymore. It runs perfect just like it did before all this fiasco started. Apparently the bike likes to have ALL the ground wires connected to the battery. When reinstalling the battery I let one get lost in the innards and overlooked it. TWICE. I disconnected the battery one more time and reconnected the wiring to it just to be sure I had everything done properly.
Was about to go after the temperature sensor with all the body work off and down amongst the coolant recovery tank there was this wire that was not connected to anything. Hmmm, looks like it should go on the negative battery post. Took out the battery bolt, hooked it up, ran like a top. Went a couple hundred miles Sunday and all is well.
Feel free to declare the Mophead Dumbass of the Year. :eek: :hehehe
Post by: The Mighty Gryphon on May 08, 2018, 07:05:44 PM
Post by: mophead on May 08, 2018, 07:24:02 PM
Post by: gone_ape on May 08, 2018, 09:24:37 PM
Post by: stokester on May 08, 2018, 11:03:15 PM
Now it's time to ride! :curvy-road
Post by: The Mighty Gryphon on May 10, 2018, 08:29:59 AM
...Clutch O-ring.
Post by: elevated on May 04, 2025, 11:57:51 AM
It is with great reluctance that I post this. The Brick does not surge anymore. It runs perfect just like it did before all this fiasco started. Apparently the bike likes to have ALL the ground wires connected to the battery. When reinstalling the battery I let one get lost in the innards and overlooked it. TWICE. I disconnected the battery one more time and reconnected the wiring to it just to be sure I had everything done properly.
Was about to go after the temperature sensor with all the body work off and down amongst the coolant recovery tank there was this wire that was not connected to anything. Hmmm, looks like it should go on the negative battery post. Took out the battery bolt, hooked it up, ran like a top. Went a couple hundred miles Sunday and all is well.
Feel free to declare the Mophead Dumbass of the Year. :eek: :hehehe
Mophead- I can imagine your reluctance to post this outcome, and I'm here to applaud your generosity. This post saved at least hours, maybe days, of my life! Diagnosing an issue with near identical symptoms to yours. I read at least a dozen threads. I was certain it was a faulty TPS, or a vacuum leak, or maybe even a bad fuel pump. Outcome: This post triggered me to realize the ground coming off the main connector was not sufficiently grounded. I moved it to the negative battery term, and therefore the battery's main ground, and BOOM, PROBLEM SOLVED! Thank you again. If you PM your address I'll send a bottle of champagne. -Jake
Post by: mophead on May 05, 2025, 04:54:01 PM
If you go back to Gryph's thread about the clutch oring that makes me feel better. Just for historical idiot things I have done in the past I rebuilt the carbs on a VFR Honda three times before I found the loose spark cable that was making it miss. If I had to do this for a living I would starve to death.
Happy you found your issue due to my misfortune. Ride safe.