14TLC Posted May 9, 2020 Share Posted May 9, 2020 Hi Everyone I need some help about high idle issue on one R1100RT. It is the same motorcycle for which I wrote in this post https://www.bmwsporttouring.com/topic/91929-r1100rt-fuel-pump-and-strainer/?tab=comments#comment-1020368 Now I see that I have not replied back on that post, rude from me but I suppose I had to much work at the time. Back then I replaced the complete fuel pump assembly with used one in excellent condition. I also replaced all fuel lines, fuel filter and of course cleaned the fuel tank. The bike also had worn clutch since the previous owner have not adjusted the clutch cable. There was no cable slack at all and who knows for how many Km he was riding it in that condition. I did only basic things back then like change all fluids and filters, checked valve clearance and adjusted the throttle cables, changed the alternator belt and spark plugs. Even then the idle was a little bid high but balance was OK. Also, the code plug was missing and there were error codes stored about missing O2 sensor and CO Potentiometer. So, I made some wires and connected the pins for the actual bike model which is 1996 R1100RT with O2 sensor, catalytic converter and made for Swiss market. At that time the bike had about 30.000Km The current owner did not have budget to address all issues and we were sure that after 10 years of sitting in garage the bike will develop some more issues. I suggested to the owner just to put some fuel additive in the fuel for cleaning of fuel system and valves and to ride it like that just for a while to see what other issues will arise. Now, some 3.000 Km after, the owner decided to repair everything on the bike that needs to be repaired After inspection of the bike this is what I found and what I did - Replaced the clutch - Changed all fluids once again and changed oil filter - There was leaking finial drive pinion seal, so I replaced that also - I have cleaned the throttle bodies and replaced the injector seals and brass screw O-rings - Replaced the left cam chain tensioner with the new upgraded one - I adjusted the rocker arm end play and valves - I have adjusted the throttle cables - Adjusted the TPS The current state now is that the bike still has high idle. Lower than before but still high. It is about 1260 RPM. The brass screws are all the way closed. In the process of troubleshooting, this is what I have done, checked and measured - Tested for air leaks and there are no - I loosened all throttle cables giving large slack - The throttle body stop screws have not been touched and the blue paint is still there - There is no play or worn throttle body shafts - Tried with different TPS settings within the acceptable range in order not to have TPS error stored. Tried from 330 to 380 mV without any success. Tried with another TPS and also without success - Tried playing with the code plugs. Without code plug, with the Golden Brown - 30/87 code plug and with code plug that the parts fiche listed for a Swiss market (Blue 30,86,87A). Also, without any success - Checked the air temperature sensor and it is within specified values - Measured the fuel pressure and it is about 3.8 to 4 bar - I measured the O2 sensor value while the engine is running at idle and it fluctuates between 0 and 600mV - Checked the HES plate adjustment with LED tool and it is spot on per the repair manual Other than the high idle, it is a sweet running bike. At this idle speed it does not need much to balance the throttle bodies. Only ¼ turn at the left throttle body from fully closed in order to be perfectly balanced Next, I plan to check wiring from all relevant sensors to the connector of the Motronic. Any suggestions are highly appreciated Link to comment
dirtrider Posted May 9, 2020 Share Posted May 9, 2020 2 hours ago, 14TLC said: Hi Everyone I need some help about high idle issue on one R1100RT. It is the same motorcycle for which I wrote in this post https://www.bmwsporttouring.com/topic/91929-r1100rt-fuel-pump-and-strainer/?tab=comments#comment-1020368 Now I see that I have not replied back on that post, rude from me but I suppose I had to much work at the time. Back then I replaced the complete fuel pump assembly with used one in excellent condition. I also replaced all fuel lines, fuel filter and of course cleaned the fuel tank. The bike also had worn clutch since the previous owner have not adjusted the clutch cable. There was no cable slack at all and who knows for how many Km he was riding it in that condition. I did only basic things back then like change all fluids and filters, checked valve clearance and adjusted the throttle cables, changed the alternator belt and spark plugs. Even then the idle was a little bid high but balance was OK. Also, the code plug was missing and there were error codes stored about missing O2 sensor and CO Potentiometer. So, I made some wires and connected the pins for the actual bike model which is 1996 R1100RT with O2 sensor, catalytic converter and made for Swiss market. At that time the bike had about 30.000Km The current owner did not have budget to address all issues and we were sure that after 10 years of sitting in garage the bike will develop some more issues. I suggested to the owner just to put some fuel additive in the fuel for cleaning of fuel system and valves and to ride it like that just for a while to see what other issues will arise. Now, some 3.000 Km after, the owner decided to repair everything on the bike that needs to be repaired After inspection of the bike this is what I found and what I did - Replaced the clutch - Changed all fluids once again and changed oil filter - There was leaking finial drive pinion seal, so I replaced that also - I have cleaned the throttle bodies and replaced the injector seals and brass screw O-rings - Replaced the left cam chain tensioner with the new upgraded one - I adjusted the rocker arm end play and valves - I have adjusted the throttle cables - Adjusted the TPS The current state now is that the bike still has high idle. Lower than before but still high. It is about 1260 RPM. The brass screws are all the way closed. In the process of troubleshooting, this is what I have done, checked and measured - Tested for air leaks and there are no - I loosened all throttle cables giving large slack - The throttle body stop screws have not been touched and the blue paint is still there - There is no play or worn throttle body shafts - Tried with different TPS settings within the acceptable range in order not to have TPS error stored. Tried from 330 to 380 mV without any success. Tried with another TPS and also without success - Tried playing with the code plugs. Without code plug, with the Golden Brown - 30/87 code plug and with code plug that the parts fiche listed for a Swiss market (Blue 30,86,87A). Also, without any success - Checked the air temperature sensor and it is within specified values - Measured the fuel pressure and it is about 3.8 to 4 bar - I measured the O2 sensor value while the engine is running at idle and it fluctuates between 0 and 600mV - Checked the HES plate adjustment with LED tool and it is spot on per the repair manual Other than the high idle, it is a sweet running bike. At this idle speed it does not need much to balance the throttle bodies. Only ¼ turn at the left throttle body from fully closed in order to be perfectly balanced Next, I plan to check wiring from all relevant sensors to the connector of the Motronic. Any suggestions are highly appreciated Morning 14TLC Is your tachometer accurate? The usual cause of a high idle is too much air, or too much fuel, or too much spark advance, or some of those combined. If the o2 sensor is working correctly, isn't poisoned or lazy then the other sensors really don't have a lot of influence on hot engine curb idle as the engine is fueling only on o2 sensor feedback (called closed loop). You have done/checked a lot on the bike & seem to have covered most of the bases. First thing that I would try is the U.S. pink CCP (30 - 87- 87A) , that usually gives the best o2 sensor controlled idle. Then see where the o2 sensor is running (if you are getting normal (+/-) .450v crossovers at hot curb idle then it is probably fueling OK. If the fueling is working OK & you don't have any air leaks between the throttle bodies & the cylinder head then maybe put a timing light on the engine & check your max spark advance (if that is high then you might have a bit too much spark advance at hot engine curb idle. That bike being a 1996 probably means it still has the single throttle cable with a crossover cable from the L/H TB to the R/H TB. On some of those it can actually use the L/H base idle screw to hold the R/H throttle cam slightly off the R/H side base idle screw when the engine is hot (worth a check) -- With engine idling hot reach in & manually close the R/H throttle body cam against the base idle screw, see if that lowers the idle slightly. Also might not hurt to do a compression check, if the compression is high due to combustion chamber carbon buildup that can make them idle higher right there. It might just come down to having a very low friction engine so it takes less power to idle it at 1200 RPM's. If it runs good, & the o2 sensor is functioning OK, & the idle cross side balance is good then you might end up backing the base idle screws out about 1/4 or 1/2 turn then re-adjusting the TPS. Link to comment
14TLC Posted May 10, 2020 Author Share Posted May 10, 2020 Hi dirtrider, Thank you. Excellent advice from you as always. Here are my answers 23 hours ago, dirtrider said: Is your tachometer accurate? Yes. I used my electronic sync tool which has RPM measurement as well . It is very precise. Compared with the timing light tool which also has RPM measurement so both are correct 23 hours ago, dirtrider said: First thing that I would try is the U.S. pink CCP (30 - 87- 87A) , that usually gives the best o2 sensor controlled idle. I tried with this CCP and yes, it gives better O2 idle control. It lowered little bit the RPM. Now it fluctuates between 1200 and 1260 with TB balanced at this idle and fluctuation seems smoother 23 hours ago, dirtrider said: Then see where the o2 sensor is running (if you are getting normal (+/-) .450v crossovers at hot curb idle then it is probably fueling OK. It seem running between 0 and 650mV, measured with the same analogue instrument as before. Then I measured with another analogue instrument with better dampening and it shows between 200mV and 650mV. Maybe I will have to use oscilloscope next time to be more precise. 23 hours ago, dirtrider said: If the fueling is working OK & you don't have any air leaks between the throttle bodies & the cylinder head then maybe put a timing light on the engine & check your max spark advance (if that is high then you might have a bit too much spark advance at hot engine curb idle. I used timing tool on hot engine, with RPM fluctuating between 1200 and 1260 RPM, it measures about 10 degrees advance on OT mark 23 hours ago, dirtrider said: That bike being a 1996 probably means it still has the single throttle cable with a crossover cable from the L/H TB to the R/H TB. On some of those it can actually use the L/H base idle screw to hold the R/H throttle cam slightly off the R/H side base idle screw when the engine is hot (worth a check) -- With engine idling hot reach in & manually close the R/H throttle body cam against the base idle screw, see if that lowers the idle slightly. Yes, it has the single throttle cable with crossover cable. I noticed what you described here the first time I tried to adjust the cables. So I also give generous slack on the crossover cable from both sides to be sure that the pulleys are resting on stop screws. I also verified this with pressing the pulleys with my fingers while the engine is running 23 hours ago, dirtrider said: Also might not hurt to do a compression check, if the compression is high due to combustion chamber carbon buildup that can make them idle higher right there I checked the compression at hot engine with WOT. At left cylinder is 12.4 bar and on the right cylinder is 12.5 bar 23 hours ago, dirtrider said: It might just come down to having a very low friction engine so it takes less power to idle it at 1200 RPM's. This may be interesting. I noticed that when I start the engine in neutral from cold, the rear wheel is spinning a lot due to cold transmission oil. After the engine gets hotter the spinning speed is lower. In any case I can stop the wheel by my foot without much pressure. The interesting ting is that when I pull the clutch the RPM will increase slightly 23 hours ago, dirtrider said: If it runs good, & the o2 sensor is functioning OK, & the idle cross side balance is good then you might end up backing the base idle screws out about 1/4 or 1/2 turn then re-adjusting the TPS. On numerous occasions I was tempted to do this, but I am still holding off until I am 100 % sure that I checked and tried everything else Link to comment
dirtrider Posted May 10, 2020 Share Posted May 10, 2020 1 hour ago, 14TLC said: Afternoon 14TLC I tried with this CCP and yes, it gives better O2 idle control. It lowered little bit the RPM. Now it fluctuates between 1200 and 1260 with TB balanced at this idle and fluctuation seems smoother-- OK, better but it is still pretty high. It seems to be running between 0 and 650mV, measured with the same analogue instrument as before. Then I measured with another analogue instrument with better damping and it shows between 200mV and 650mV. Maybe I will have to use oscilloscope next time to be more precise.-- How quickly is it responding? Does it continually cross the .450v mid range or does it stay mostly on one side of .450v? I used timing tool on hot engine, with RPM fluctuating between 1200 and 1260 RPM, it measures about 10 degrees advance on OT mark -- If you revv the engine until the timing quits advancing does it go past (above) the flywheel Z mark? Yes, it has the single throttle cable with crossover cable. I noticed what you described here the first time I tried to adjust the cables. So I also give generous slack on the crossover cable from both sides to be sure that the pulleys are resting on stop screws. I also verified this with pressing the pulleys with my fingers while the engine is running-- OK, that clarifies & eliminates this possibility. I checked the compression at hot engine with WOT. At left cylinder is 12.4 bar and on the right cylinder is 12.5 bar-- OK, high side of normal but I have seen quite a few within that range , service book shows 10 bar as normal. This may be interesting. I noticed that when I start the engine in neutral from cold, the rear wheel is spinning a lot due to cold transmission oil. After the engine gets hotter the spinning speed is lower. In any case I can stop the wheel by my foot without much pressure. The interesting thing is that when I pull the clutch the RPM will increase slightly-- Perfectly normal, the transmission is a constant mesh so the free-spinning-gears drive the shafts they are on through cold (high viscosity) oil friction. On numerous occasions I was tempted to do this, but I am still holding off until I am 100 % sure that I checked and tried everything else-- You might end up eventually doing this. If you record how much you move the base idle screws then you can always put them back if you want. (or take close-up pictures before you move them). Link to comment
14TLC Posted May 13, 2020 Author Share Posted May 13, 2020 Hi dirtrider, On 5/10/2020 at 5:03 PM, dirtrider said: It seems to be running between 0 and 650mV, measured with the same analogue instrument as before. Then I measured with another analogue instrument with better damping and it shows between 200mV and 650mV. Maybe I will have to use oscilloscope next time to be more precise.-- How quickly is it responding? Does it continually cross the .450v mid range or does it stay mostly on one side of .450v? Yes, it continuously cross the .450V. I would describe it as perfect sine wave with holding just about the same time at both negative and positive amplitudes. It needs quite a bit time until the O2 sensor start acting. From cold start it will start rising slowly until reaches 800mV. It will stay there until the temperature on RID show s 2 bars. Until that point the RPM is steady at 1240 - 1260. Then it will start fluctuating and RPM will start fluctuating more. The RPM at cold start is about 1100-1150 On 5/10/2020 at 5:03 PM, dirtrider said: I used timing tool on hot engine, with RPM fluctuating between 1200 and 1260 RPM, it measures about 10 degrees advance on OT mark -- If you revv the engine until the timing quits advancing does it go past (above) the flywheel Z mark? Today I measured the advance again and today it is about 12-13 degrees advance on OT mark. The only time I can see the Z mark is when I set the timing light to 0 degrees offset and rev the engine to about 3700 RPM. The Z mark will appear from the upper part of the TDC hole Link to comment
dirtrider Posted May 13, 2020 Share Posted May 13, 2020 17 minutes ago, 14TLC said: Hi dirtrider, Yes, it continuously cross the .450V. I would describe it as perfect sine wave with holding just about the same time at both negative and positive amplitudes. It needs quite a bit time until the O2 sensor start acting. From cold start it will start rising slowly until reaches 800mV. It will stay there until the temperature on RID show s 2 bars. Until that point the RPM is steady at 1240 - 1260. Then it will start fluctuating and RPM will start fluctuating more. The RPM at cold start is about 1100-1150 Today I measured the advance again and today it is about 12-13 degrees advance on OT mark. The only time I can see the Z mark is when I set the timing light to 0 degrees offset and rev the engine to about 3700 RPM. The Z mark will appear from the upper part of the TDC hole Afternoon 14TLC o2 sensor function sounds OK. Do you have your adjustable advance timing light set to the 2 cycle, or single cylinder, or one flash per revv setting? Remember, to an adjustable advance timing light the BMW boxer, with a lost spark igniton system, looks like a single cylinder 2 cycle engine (one spark for every piston up). At 4K (or when the advance reaches full advance) the Z should be somewhat centered in the timing hole. You are running out of easy options, if you can't find an air leak, or high timing (the fueling part looks to be good) then your options are limited & you might have to back the base idle screws out a little. Link to comment
14TLC Posted May 13, 2020 Author Share Posted May 13, 2020 Hi dirtrider 1 hour ago, dirtrider said: Do you have your adjustable advance timing light set to the 2 cycle, or single cylinder, or one flash per revv setting? Remember, to an adjustable advance timing light the BMW boxer, with a lost spark igniton system, looks like a single cylinder 2 cycle engine (one spark for every piston up). Exactly. I set the timing light to 2 stroke engine to display correct RPM. When set to 4 stroke the RPM reading is multiplied by 2. Regarding timing, it does not make a difference whether is set to 2 or 4 stroke engine. 2 hours ago, dirtrider said: At 4K (or when the advance reaches full advance) the Z should be somewhat centered in the timing hole. I did not try to go to 4K. At 3.7K the Z mark was visible in the upper half of the timing hole. I try tomorrow at 4K to see if it lines up in the middle. If it does not, what do you suggest? To try adjusting the HES plate a little, or go directly and back the base idle screws a little? Link to comment
dirtrider Posted May 13, 2020 Share Posted May 13, 2020 6 minutes ago, 14TLC said: I did not try to go to 4K. At 3.7K the Z mark was visible in the upper half of the timing hole. I try tomorrow at 4K to see if it lines up in the middle. If it does not, what do you suggest? To try adjusting the HES plate a little, or go directly and back the base idle screws a little? Afternoon 14TLC As long as the Z is in the hole somewhere then probably close enough as it isn't off far enough to cause your high idle. Link to comment
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