Idle speed increases while bike warms up - BMW Luxury Touring Community
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post #1 of 28 Old Apr 13th, 2020, 3:05 pm Thread Starter
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Idle speed increases while bike warms up

2002 LT with 80K miles

The background first.
Last spring I:
- replaced internal and external fuel lines
- replaced oxygen sensor
- replaced crankcase ventilation manifold with a copper one I made from ideas on this forum
- sent fuel injectors to Mr. Injector
- cleaned throttle bodies
I didnít adjust the throttle cables at that time, nor was I able to take it for a test ride due to a medical issue.

Fast forward to the present, after waiting a year to let the medical issue get behind me.

I tried to perform the throttle cable adjustment procedure today. I have the upgraded cables, by the way. I removed the cable end cover at the throttle grip so I could see the free play, and I opened up the free play on both cables to the recommended 4-5 mm. The cruise control cable is in the 2-3 mm free play range. I left the cable end cover off.

I started the engine and it began to idle at 1,000 rpm. After a few minutes, the idle speed began to climb, ultimately getting to about 1,400 rpm when the temp gauge was about at the halfway point. I checked both throttle cables and they still had plenty of free play, so I decided to turn the engine off because it seemed the idle speed increase was being caused by something other than a tight cable.

Iíd appreciate any thoughts on what I should check.

Thanks,
Ken

Ken Davis
Mobile, AL
2002 LT
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post #2 of 28 Old Apr 13th, 2020, 4:46 pm
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Re: Idle speed increases while bike warms up

The most likely cause would be an air leak. Check those 4 hoses that attach to the left side of the throttle body and if a US model, to the purge valve for cracks or maybe one is popped off. The rubber boots between the TB and the block may have cracked and is allowing in unwanted air or possibly the O-rings between the bolt on manifolds that the TB attaches to and the block. How much of the TB and manifolds did you take off to do the vent pipe and cleaning?
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post #3 of 28 Old Apr 13th, 2020, 8:39 pm
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Re: Idle speed increases while bike warms up

Double check that all the return springs are in place. I had a guy helping me work his bike and we pulled the TB off and he proceeded to clean them. When we reinstalled them the engine ran like crap (long story it was a hole in a piston) so we looked for another engine, found one and installed every thing 3 months later and the bike ran like crap again and the idle went up as it warmed up. Trouble shooting showed the TSP was way out of alignment but we never messed with it. Finally found one of the return springs off and once it was hooked back up the TSP read spot on and the bike ran fine. Just another thing to check.
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John
2009 K1300GT Red Rocket
2009 R1200GS (Gone)
2005 K1200LT Ocean Blue Blue Wizard 114 K and counting...
2006 Bushtec Turbo+2 Spell
2004 330 Ci Convertable
K4AN

Have ridden a Motorcycle in all 48
But lack DE, MA, RI and CT with the 2005 LT

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post #4 of 28 Old Apr 14th, 2020, 3:58 pm Thread Starter
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Re: Idle speed increases while bike warms up

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Originally Posted by bmwcoolk1200 View Post
The most likely cause would be an air leak. Check those 4 hoses that attach to the left side of the throttle body and if a US model, to the purge valve for cracks or maybe one is popped off. The rubber boots between the TB and the block may have cracked and is allowing in unwanted air or possibly the O-rings between the bolt on manifolds that the TB attaches to and the block. How much of the TB and manifolds did you take off to do the vent pipe and cleaning?
Thanks, Gordon. Everything from the crankcase up was removed. I did put new O-rings between the intake manifolds and the crankcase. Iíll remove everything this weekend and check for cracks. All the vacuum hoses appear to be connected properly.

Ken
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Ken Davis
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post #5 of 28 Old Apr 14th, 2020, 4:01 pm Thread Starter
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Re: Idle speed increases while bike warms up

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Double check that all the return springs are in place. I had a guy helping me work his bike and we pulled the TB off and he proceeded to clean them. When we reinstalled them the engine ran like crap (long story it was a hole in a piston) so we looked for another engine, found one and installed every thing 3 months later and the bike ran like crap again and the idle went up as it warmed up. Trouble shooting showed the TSP was way out of alignment but we never messed with it. Finally found one of the return springs off and once it was hooked back up the TSP read spot on and the bike ran fine. Just another thing to check.
Thanks, John. Iíll remove everything this weekend and check the return springs.

Ken

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2002 LT
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post #6 of 28 Old Apr 25th, 2020, 1:52 pm Thread Starter
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Re: Idle speed increases while bike warms up

Finally had some time to check the vacuum lines and intake manifold bushing for cracks that would allow air leaks. Found none. Also, the three throttle springs are properly attached.

Another bit of info. Attached is a pic with the arrow pointing to what I think is a stop screw. When I had the bike together and was experiencing increasing idle speed, I noticed that by turning the throttle toward the close position from its normal stop position I could get the idle speed to reduce to its normal 1,000 rpm. This morning, after I removed the tank and air box, I rolled the throttle on and let it go back to its stop position without letting it snap back. I then turned the throttle toward the close position and noticed the ďstop screwĒ moved about 1 mm to where it touched the rail. This would seem to match the reduction in idle speed noted earlier. Thoughts?

Thank, Ken
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post #7 of 28 Old Apr 25th, 2020, 2:15 pm
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Re: Idle speed increases while bike warms up

There is a stop screw under that point and it is a hard one. That whole arm is controlled by the throttle actuator, it is a stepper motor that sets the idle speed. Usually this works OK unless you have bent the bracket that holds it to the TB. I have included some info on how it operates. Make sure the connector is on correctly (i.e. locked).

Also the cable play is supposed to be 0.5 mm on each cable, total of 1 mm (engine warm). Don't know where you got 4-5 mm.
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John
2009 K1300GT Red Rocket
2009 R1200GS (Gone)
2005 K1200LT Ocean Blue Blue Wizard 114 K and counting...
2006 Bushtec Turbo+2 Spell
2004 330 Ci Convertable
K4AN

Have ridden a Motorcycle in all 48
But lack DE, MA, RI and CT with the 2005 LT

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post #8 of 28 Old Apr 25th, 2020, 4:26 pm Thread Starter
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Re: Idle speed increases while bike warms up

The 4-5 mm is what understand is the initial free play when adjusting the cables. I left it at that so there would be no effect on idle speed from a cable being too tight. At least, that was my thinking. Iíll read what you sent.

Thanks,
Ken

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post #9 of 28 Old Apr 25th, 2020, 5:41 pm
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Re: Idle speed increases while bike warms up

Quote:
Originally Posted by bmwcoolk1200 View Post
The most likely cause would be an air leak. Check those 4 hoses that attach to the left side of the throttle body and if a US model, to the purge valve for cracks or maybe one is popped off. The rubber boots between the TB and the block may have cracked and is allowing in unwanted air or possibly the O-rings between the bolt on manifolds that the TB attaches to and the block. How much of the TB and manifolds did you take off to do the vent pipe and cleaning?


Good info, If it ever happens to my "02, I can check these things.
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post #10 of 28 Old Apr 28th, 2020, 11:17 am Thread Starter
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Re: Idle speed increases while bike warms up

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Originally Posted by jzeiler View Post
There is a stop screw under that point and it is a hard one. That whole arm is controlled by the throttle actuator, it is a stepper motor that sets the idle speed. Usually this works OK unless you have bent the bracket that holds it to the TB. I have included some info on how it operates. Make sure the connector is on correctly (i.e. locked).

Also the cable play is supposed to be 0.5 mm on each cable, total of 1 mm (engine warm). Don't know where you got 4-5 mm.
John,

Thanks for the info.

I want to take this step by step. I removed the throttle actuator and tested it on the bench. The pistonís retracted length was 36 mm and the extended length was 44 mm, right on the target lengths. The resistance between pins 1 and 2 was 11 ohms, weíll below the max of 2,000 ohms. With the ohm meter on pins 3 and4, there was continuity when the piston end was compressed, and no continuity when it was not compressed. Since the actuator checked out I reinstalled it on its bracket using blue loctite and 5 Nm of torque.

I then read the procedure to adjust the actuator. It says the throttle position sensor (potentiometer) should be in the range of .34 to .38 volts. I donít know how to test that. Help, please.

Thanks,
Ken

Ken Davis
Mobile, AL
2002 LT
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post #11 of 28 Old Apr 28th, 2020, 11:29 am
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Re: Idle speed increases while bike warms up

Not and easy thing to do unless you have a GS-911 unit. It has a check function to see if the TPS is reading correctly. This is how I discovered a missing return spring on a bike I worked on. The 911 unit said TPS was out of range and once I re-hooked up the missing spring it read in range. Maybe some one down your way has one and can help out.

There is a section here that you can do with the TB off the bike to test it. I think John in Canada (sailor) made up both of these guides on the TVA and TPS.
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John
2009 K1300GT Red Rocket
2009 R1200GS (Gone)
2005 K1200LT Ocean Blue Blue Wizard 114 K and counting...
2006 Bushtec Turbo+2 Spell
2004 330 Ci Convertable
K4AN

Have ridden a Motorcycle in all 48
But lack DE, MA, RI and CT with the 2005 LT

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post #12 of 28 Old Apr 28th, 2020, 3:57 pm Thread Starter
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Re: Idle speed increases while bike warms up

Thanks, John. Sounds like itís time to find a GS-911.

Ken

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post #13 of 28 Old Apr 28th, 2020, 8:56 pm
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Re: Idle speed increases while bike warms up

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John,

Thanks for the info.

I want to take this step by step. I removed the throttle actuator and tested it on the bench. The piston’s retracted length was 36 mm and the extended length was 44 mm, right on the target lengths. The resistance between pins 1 and 2 was 11 ohms, we’ll below the max of 2,000 ohms. With the ohm meter on pins 3 and4, there was continuity when the piston end was compressed, and no continuity when it was not compressed. Since the actuator checked out I reinstalled it on its bracket using blue loctite and 5 Nm of torque.

I then read the procedure to adjust the actuator. It says the throttle position sensor (potentiometer) should be in the range of .34 to .38 volts. I don’t know how to test that. Help, please.

Thanks,
Ken
1) About TPS:
---------------
JZEILER has already posted an older version of a document I made about this. I have attached a more recent version (from 2019) where I made minor additions and clarifications. As explained in this document, the TPS can be checked with a good Voltmeter (or a GS911) HOWEVER for both methods the TVA (idle actuator) need to be temporarely unbolted and unplugged so that the TPS base setting is measured at the mechanical idle-stop - not at the higher idle position as compensated by the TVA pushing on it.

Removing the TVA should be done with ignitition OFF, howevere the ignition need to be turned ON after to make the TPS measurements. The EFI system will log an error code into memory as it will see the TVA was disconnected (or not responding to piston movement). If you do not have a GS911 to clear all error codes after you are done, then you can use the followin method instead:
- Once teh TPS check is done, turn igniton is OFF,
- remove the EFI fuse from the fuse box for 20 minutes or more (overnight is not a problem),
- install the EFI fuse, make sure the throttle is closed completely (clicking at idle-stop) JUST BEFORE the next ignition ON cycle. This is important as teh EFI system will reset some internal values based on what it sees on the TPS at that point. At ignition ON moment, playing with the throttle or not having it t idle-stop will confuse the whole system.

It is IMPORTANT to note that this document does NOT cover what to do if the main idle-stop screw (under the rail) or any of the 3 linkage screws have been tampered with. In such case, even adjusting the TPS would not fix an incorrect relationship. The TPS voltage at idle-stop (0.34 to 0.37) assumes the air-intake / Vacuum is exact as set at the factory - this is why they put Blue tamper proof paint on these screws.

I have tampered with these for testing many setups, but CANNOT suggest anyone here should do it unless you have another CORRECT complete Throttle-body assy to replace the one you have messed up ;-)


2) About the TVA:
-------------------
note that even if yours has passed all the test of the other PDF about the TVA, the whole EFI system will not work properly IF either or both of these conditions exist:
- the screws behind the TVA piston (attached to TB #3) has been tampered with

- the bracket holding the TVA to the Throttle-body assy has been slightly bent - this is quite common as I have seen many fight with the TB assy to pull it out of the 4 manifolds stubs - in some cases they make the mistake to use this bracket for leverage.
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K1200RS (2002 IceBlue/Red - 96,000 miles)
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post #14 of 28 Old May 2nd, 2020, 9:50 am Thread Starter
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Re: Idle speed increases while bike warms up

Thanks, Sailor.

This is all pretty daunting to me. Early on I did a visual check for cracks that would lead to a vacuum leak, but found none. Before l jump into testing the TPS, I think Iíll use some smoke to test for any vacuum leaks below the throttle butterfly valves, just to make sure that isnít my problem.

I donít think I bent the TVA bracket when removing and replacing it. Last weekend, when I had the TVA on the bench for testing, I took a straightedge, placed it on the bracket in several positions, and couldnít find any gaps, so I donít think itís bent.

I havenít tampered with the idle stop screw or the three screws attaching the TVA bracket to the throttle body rail, so I should be good there.

Iíll report back with the smoke test results.

Thanks,
Ken

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2002 LT
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Re: Idle speed increases while bike warms up

The smoke test revealed a small leak on #3 throttle body position where the rubber boot on the bottom of the throttle body joins the intake manifold. It was coming from under the bottom clamp, so I tightened it. Tested again and this leak seems to be fixed, but there was a tiny bit of smoke that seemed to come from around the top of the boot. The fuel rail was in the way and I couldnít see exactly where the smoke was coming from, so Iíll now remove the fuel rail and do another smoke test.

Ken

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post #16 of 28 Old May 14th, 2020, 4:44 pm Thread Starter
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Re: Idle speed increases while bike warms up

After putting everything except the Tupperware back on I started the bike and the idle still kept creeping up to 1,400 rpm. I decided to remove the throttle body and bench test the TPS according to Sailorís instructions. Here are the results. First, I removed the TVA from the throttle body rail. Testing between pins 1 and 2 yielded resistance of 1,465 ohms with throttle closed and 805 ohms at approximately 23 degrees open. Both readings are well outside of the acceptable range in Sailorís procedure. Next, testing between pins 2 and 3 yielded 960 ohms at full throttle and 1,680 ohms at approximately 23 degrees open. Again, both readings are outside the acceptable range. Last, testing between pins 2 and 4 yielded 705 ohms throughout the throttle range. As with the other two tests, this reading is outside the acceptable range.

Now whatís the next step? Mark the present location of the TPS, then loosen the screws and rotate the TPS to where the ohm readings are within the acceptable range? Buying a GS-911 is not realistic right now and I donít know anyone close to me who has one.

Thanks,
Ken

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2002 LT
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post #17 of 28 Old May 14th, 2020, 5:47 pm
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Re: Idle speed increases while bike warms up

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After putting everything except the Tupperware back on I started the bike and the idle still kept creeping up to 1,400 rpm. I decided to remove the throttle body and bench test the TPS according to Sailor’s instructions. Here are the results. First, I removed the TVA from the throttle body rail. Testing between pins 1 and 2 yielded resistance of 1,465 ohms with throttle closed and 805 ohms at approximately 23 degrees open. Both readings are well outside of the acceptable range in Sailor’s procedure. Next, testing between pins 2 and 3 yielded 960 ohms at full throttle and 1,680 ohms at approximately 23 degrees open. Again, both readings are outside the acceptable range. Last, testing between pins 2 and 4 yielded 705 ohms throughout the throttle range. As with the other two tests, this reading is outside the acceptable range.

Now what’s the next step? Mark the present location of the TPS, then loosen the screws and rotate the TPS to where the ohm readings are within the acceptable range? Buying a GS-911 is not realistic right now and I don’t know anyone close to me who has one.

Thanks,
Ken
The PDF file includes the OHMS reading so that a quick / check compare could be done in a static manner WITH IGNITION OFF (no power applied to TPS so no risk to damage something).
In such variable resistor, the OHMS checks across the full range allows to see if either resistance track are skipping values (a bad contact while turning TPS).

I would not worry with these lower OHMS values until we have further VOLTs tests:
Most of my test were done on the K1200RS engine , however there is some evidences that many K1200LT came with a higher TPS voltage at idle from factory (meaning a lower resistance at idle stop). BMW never documented any of this, BUT these facts came out while I compared the base TPS setting or K1200RS -vs- K1200LT using a GS911.

In your case, 1465 mentionned above is a bit too low and should create a TPS voltage that is too high (more on this below).

As explained in the document - as best I could - the IMPORTANT tests are the ones with the Voltmeter. This is located in next docment section following the OHMS checks. One has to be CARFULL as these Volts tests are important BUT they are also done live with ignition ON - using temp wires. For example if you short the temp wire coming out of Pin #1 on TPS by touching something metalic on frame you could damage the ECU unit.

Although not modified in my document, on a K1200LT, even you see as much as 0.41 volts at idle stop (instead of 0.33 to 0.38), I would NOT move/change the TPS . If you need to lower the TPS voltage (target is 0.38 to 0.40 for a K1200LT) rotate the TPS clockwise as seen if you looked at the Throttle/TPS assy from the rear of the bike.

If you find it is already acceptable (from 0.36 tp 0.41 volts) THEN you would need to further your investigation into OTHER "potential" causes:
1) the blue painted screws have been tampered with (these TPS values assumes the butterfly position are set at factory and not touched later)

2) there might still be some intake air-leaks

3) the TVA is defective or incorrectly set (this can be checked "indirectly" by starting warm without a TVA bolted)

4) The engine coolant sensor located on the rear-most cylinder-head is giving false data to the ECU. We have seen some cases were the ECU "was being told" the engine was still cold (when in fact it was not). In such case, the ECU continues to keep the idle high until it sees the engine warmer. Of course that wrong data feedback can go on for a long time in some isolated failure of the sensor.

I did a very brief photo album tutorial for checking the static values of the engine coolant sensor (engine OFF, engine warmed up or cold) - try either links in case the 1st one will not work for you - IMPORTANT to click on each photo to read attached notes that show up below OR on right of photo.

Once the engine is warning up, you can stop it (ignition OFF) and take another reading at the sensor wires unplugged: for each 10 degrees (F) higher in coolant temp, the resistance goes goes down - fast at first, then slower (graph is a curve). From 2500 Ohms at 70 deg (F) to about 260 Ohms when in normal "middle range" on dash gauge.

IMPORTANT: if you forget to plug it back and turn ignition ON while the Engine Coolant is still disconnected, you will hear both radiator fans run full time - this a "failed safe mode" of the ECU when it cannot read a proper engine coolant temp.
https://photos.google.com/album/AF1Q...zVu6FWt33uK0yb

https://get.google.com/albumarchive/...zVu6FWt33uK0yb

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K1200RS (2002 IceBlue/Red - 96,000 miles)
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Last edited by sailor; May 14th, 2020 at 8:37 pm.
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post #18 of 28 Old May 15th, 2020, 2:43 pm Thread Starter
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Re: Idle speed increases while bike warms up

Thanks, Sailor. Iíll attempt the additional tests this weekend and report back.

Ken

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post #19 of 28 Old May 16th, 2020, 2:09 pm Thread Starter
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Re: Idle speed increases while bike warms up

Sailor,
I performed the TPS volts test with the TVA unplugged and removed from the throttle body rail. Results are .50 volts at idle stop and increasing in a linear fashion to 4.64 volts at approximately 23 degrees open throttle and remaining there to full throttle. It appears I need to rotate the TPS to get the low end into the LT target range of .38 to .40 volts. BTW, the blue paint on the idle stop screw under the rail has never been broken. Is there anything else that I should do at this point (the TVA will be reset according to your TVA write-up).
Thanks,
Ken
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post #20 of 28 Old May 16th, 2020, 2:43 pm
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Re: Idle speed increases while bike warms up

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Originally Posted by kend52 View Post
Sailor,
I performed the TPS volts test with the TVA unplugged and removed from the throttle body rail. Results are .50 volts at idle stop and increasing in a linear fashion to 4.64 volts at approximately 23 degrees open throttle and remaining there to full throttle. It appears I need to rotate the TPS to get the low end into the LT target range of .38 to .40 volts. BTW, the blue paint on the idle stop screw under the rail has never been broken. Is there anything else that I should do at this point (the TVA will be reset according to your TVA write-up).
Thanks,
Ken
My rought gess is thatr 0.50 volts could cause minor increase in fuel delivery ANd/OR in idle RPM. From almost Zero up until about 2000 RPM, using the TVA, the ECU can increase / reduce RPM indirectly based on many factors: the most important are the engine-coolant and the TPS. EVEN if the main fuel rail screw has not been touched, it is always possible one or 4 of the individual linking/sync adjuster have been touched (these are on top). These adjuster also have blue paint, but the paint tend to go or flake away over time.

YES, you should set lower to 0.38 to 0.40 - it is quite sensitive and does not require much rotation.
After every adjust and tigntening of the 2 TPS Torx bolts, you need to recheck your value as making it tight will change the position slighly.

ALSO, after you are done with TB work, AND BEFORE your start the engine, you should remove the EFI/ECU fuse for 30 minutes. This will clear some fault codes and reset the ECU to read newer values at next igntion ON cycle. You can disconnect negative battery cable for 30 minutes to achieve same result, but it is simpler and less risk to play with 1 fuse.

For the TVA, before you do your first engine start, it is suggested to put it at low piston position before mounting on TB - using any battery sourcefrom between 6 to 12 volts and 2 short jumper wires this is easy to do with TVA on bench (a bit more difficult to install these 2 jumpers with TVA in place on TB on engine).
The idea behind this TVA at low and the 30 minutes fuse delay, is that:
- once the ECU memory is empty, at the next Ignition ON cycle. it reads newer settings and play the game to move TVA according to new TPS voltage it reads

- also, it is VERY IMPORTANT not to touch / increase the throttle grip during or immediately after start. This is even more important after work on TB and with the ECU memory cleared. In fact, this is a sin on most fueld injected cars also - many are committing it by habit with old carb engine. Cold or Hot , a properly tuned EFI engine will manage the idle speed increase (if needed) and the richer mixture (if needed based on sensors data including TPS).

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K1200RS (2002 IceBlue/Red - 96,000 miles)
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post #21 of 28 Old May 16th, 2020, 7:49 pm Thread Starter
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Re: Idle speed increases while bike warms up

Thanks, Sailor. I should have time tomorrow afternoon to reset the TPS. With the throttle body rail off the bike I noticed one of the bushings between the throttle body and the intake manifold was cracked on the outside but the crack didnít go all the way through. Nevertheless, the bushings are 18 years old, so Iíll replace them before I put everything back together. Thank you for all your help. Iíll report back when I get the bushings replaced.

Ken

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Mobile, AL
2002 LT
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post #22 of 28 Old May 17th, 2020, 7:14 am
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Re: Idle speed increases while bike warms up

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Originally Posted by kend52 View Post
Thanks, Sailor. I should have time tomorrow afternoon to reset the TPS. With the throttle body rail off the bike I noticed one of the bushings between the throttle body and the intake manifold was cracked on the outside but the crack didnít go all the way through. Nevertheless, the bushings are 18 years old, so Iíll replace them before I put everything back together. Thank you for all your help. Iíll report back when I get the bushings replaced.

Ken
On ANY K1200LT/RS engine that has symptoms related to intake air-leaks, one should ALWAYS replace ALL THESE PARTS - it is so time consuming to go back that one does want to go piece-by-piece and replace only a few:
1) the 4 O-ring under the intake manifolds AND clean / check surface between cylinder-head and manifolds. The plastic-like manifolds have a tendency to wrap over time and not seal properly anymore (under surface to cylinder-head).
2) the 4 intake rubber stubs between manifolds and TB assy (may need some new clamp in some cases)
3) the 4-into-one cranckase to intake breather/vent system (rubber part between top of engine cranckcase and the TB)

My past past wrenching experience ANd the following of hundreds of riders on 3 different K1200 forums has shown that in 80% of cases the problem symptoms have been eliminated after a PROPER job of replacing these.
The symptoms are typically:
a) difficult cold OR hot start with unstable idle (in general too high idle) assuminfg the other "basic" tune-up items have been eliminated BEFORE
b) constant too hight idle (sometimes fluctuating)

OF course there are a fews exceptions like:
- If you have always done the maintenance yourselft since new and you know these parts have been replace LESS than 4 years ago (on averag they will cause "potential" problem every 8 years). STILL... you should double check your work in case of symptoms

- If you have an invoice from YOUR dealer that shows these have been replaced less than 4 years ago

-------------------------------------------------
John (Montreal, CANADA)
K1200RS (2002 IceBlue/Red - 96,000 miles)
-------------------------------------------------
Think twice before you hit [SUBMIT REPLY] - famous quote by another member:
"The value of this board is not founded on dismissing the ideas of others, but by posting to share our experiences and what we've learned from them."
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post #23 of 28 Old May 17th, 2020, 4:26 pm Thread Starter
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Location: Mobile, AL, USA
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Re: Idle speed increases while bike warms up

Quote:
Originally Posted by sailor View Post
On ANY K1200LT/RS engine that has symptoms related to intake air-leaks, one should ALWAYS replace ALL THESE PARTS - it is so time consuming to go back that one does want to go piece-by-piece and replace only a few:
1) the 4 O-ring under the intake manifolds AND clean / check surface between cylinder-head and manifolds. The plastic-like manifolds have a tendency to wrap over time and not seal properly anymore (under surface to cylinder-head).
2) the 4 intake rubber stubs between manifolds and TB assy (may need some new clamp in some cases)
3) the 4-into-one cranckase to intake breather/vent system (rubber part between top of engine cranckcase and the TB)

My past past wrenching experience ANd the following of hundreds of riders on 3 different K1200 forums has shown that in 80% of cases the problem symptoms have been eliminated after a PROPER job of replacing these.
The symptoms are typically:
a) difficult cold OR hot start with unstable idle (in general too high idle) assuminfg the other "basic" tune-up items have been eliminated BEFORE
b) constant too hight idle (sometimes fluctuating)



OF course there are a fews exceptions like:
- If you have always done the maintenance yourselft since new and you know these parts have been replace LESS than 4 years ago (on averag they will cause "potential" problem every 8 years). STILL... you should double check your work in case of symptoms

- If you have an invoice from YOUR dealer that shows these have been replaced less than 4 years ago
I adjusted the TPS to yield 0.39 volts at idle stop. Checked it after tightening the TPS Torx bolts. After that I checked resistance values of the TPS on the bench. They changed a little. Pins 1 and 2 now read 1450 ohms at idle stop and 800 at 23 degrees open. Pins 2 and 3 read 990 at full throttle and 1680 at 23 degrees. Pins 2 and 4 read 705 ohms throughout the throttle range.

A little over a year ago, I replaced the O-rings under the intake manifolds and cleaned the manifold and cylinder head surfaces, but I didnít check for warping. I will do that and use new O-rings. I also replaced the 4-into-1 crankcase to intake breather/vent system with one I made from copper tubing from instructions on this site. Will also replace the 4 intake rubber stubs and clamps.

Next steps will be to check for intake manifold warping, order parts, and reassemble everything. Sailor, Iíll follow your instructions about what to do before starting the engine - remove EFI/ECU fuse for 30 minutes and put the TVA piston at the low position before mounting it on the rail.

Thanks,
Ken

Ken Davis
Mobile, AL
2002 LT
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post #24 of 28 Old May 17th, 2020, 4:36 pm
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Re: Idle speed increases while bike warms up

Quote:
Originally Posted by kend52 View Post
I adjusted the TPS to yield 0.39 volts at idle stop. Checked it after tightening the TPS Torx bolts. After that I checked resistance values of the TPS on the bench. They changed a little. Pins 1 and 2 now read 1450 ohms at idle stop and 800 at 23 degrees open. Pins 2 and 3 read 990 at full throttle and 1680 at 23 degrees. Pins 2 and 4 read 705 ohms throughout the throttle range.

A little over a year ago, I replaced the O-rings under the intake manifolds and cleaned the manifold and cylinder head surfaces, but I didn’t check for warping. I will do that and use new O-rings. I also replaced the 4-into-1 crankcase to intake breather/vent system with one I made from copper tubing from instructions on this site. Will also replace the 4 intake rubber stubs and clamps.

Next steps will be to check for intake manifold warping, order parts, and reassemble everything. Sailor, I’ll follow your instructions about what to do before starting the engine - remove EFI/ECU fuse for 30 minutes and put the TVA piston at the low position before mounting it on the rail.

Thanks,
Ken
ALSO, remember what I posted a few days ago about checking the coolant sensor static resistance at various engine temp. After the intake air-leaks, the next culprit in having unexplained too hight idle is this.

History shows the coolant sensor defect is certainly not common (not like intake air-leaks), however, it quite easy to do with very little removal of parts - you only need to reach the end connector. Follow the photo album I posted with the notes on every photo (on right or below depending on Google and browser).

-------------------------------------------------
John (Montreal, CANADA)
K1200RS (2002 IceBlue/Red - 96,000 miles)
-------------------------------------------------
Think twice before you hit [SUBMIT REPLY] - famous quote by another member:
"The value of this board is not founded on dismissing the ideas of others, but by posting to share our experiences and what we've learned from them."
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post #25 of 28 Old May 17th, 2020, 9:13 pm Thread Starter
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Location: Mobile, AL, USA
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Re: Idle speed increases while bike warms up

Quote:
Originally Posted by sailor View Post
ALSO, remember what I posted a few days ago about checking the coolant sensor static resistance at various engine temp. After the intake air-leaks, the next culprit in having unexplained too hight idle is this.

History shows the coolant sensor defect is certainly not common (not like intake air-leaks), however, it quite easy to do with very little removal of parts - you only need to reach the end connector. Follow the photo album I posted with the notes on every photo (on right or below depending on Google and browser).
Yes, I meant to post that. I did the test according to your instructions. At 84 degrees Fahrenheit right at the sensor the resistance was 1,834 ohms. Iíll have a chance to check it again early Tuesday morning when hopefully the temperature will be lower.

Thanks,
Ken
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post #26 of 28 Old May 19th, 2020, 10:07 am Thread Starter
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Re: Idle speed increases while bike warms up

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Originally Posted by kend52 View Post
Yes, I meant to post that. I did the test according to your instructions. At 84 degrees Fahrenheit right at the sensor the resistance was 1,834 ohms. Iíll have a chance to check it again early Tuesday morning when hopefully the temperature will be lower.

Thanks,
Ken
I tested the coolant sensor this morning when the temperature at the sensor was 79 degrees Fahrenheit. Resistance was right at 2,000 ohms. It appears the coolant sensor is fine.

Also removed the four intake manifolds and checked for warping. None showed any signs of warping after using a steel straight edge at several different angles on each manifold. The steel tubes through which the bolts go extend a tiny bit from the bottom of the manifolds, such that the clearance between the bottom of the plastic part of each manifold and a flat granite counter top was 0.13 mm. Sitting each manifold on the counter top and looking a light passing through that gap showed an even line of light. It appears the manifolds don't need to be replaced, but I will replace the O-rings.

Thanks for all your help, Sailor. It will be a couple of weeks before I get the parts, put everything back together, and report back.

Thanks,
Ken

Ken Davis
Mobile, AL
2002 LT
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post #27 of 28 Old May 19th, 2020, 10:52 am
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Re: Idle speed increases while bike warms up

Quote:
Originally Posted by kend52 View Post
I tested the coolant sensor this morning when the temperature at the sensor was 79 degrees Fahrenheit. Resistance was right at 2,000 ohms. It appears the coolant sensor is fine.

Also removed the four intake manifolds and checked for warping. None showed any signs of warping after using a steel straight edge at several different angles on each manifold. The steel tubes through which the bolts go extend a tiny bit from the bottom of the manifolds, such that the clearance between the bottom of the plastic part of each manifold and a flat granite counter top was 0.13 mm. Sitting each manifold on the counter top and looking a light passing through that gap showed an even line of light. It appears the manifolds don't need to be replaced, but I will replace the O-rings.

Thanks for all your help, Sailor. It will be a couple of weeks before I get the parts, put everything back together, and report back.

Thanks,
Ken
Thanks for the update on the coolant sensor. DO NOT FORGET you still need to do a good check of resistance after the engine has been warned up to confirm resistance is in fact going down.

As per my previous instructions: you warm up engine, TAKE NOTE about where the engine temp on dash was, turn ignition OFF, unplug sensor, and do the static OHMS measurement again. If you have a very good "Infrared non-contact gun thermometer", you can aim it near where the sensor is plugged (rear-most cylinder head) to get a better approximation - otherwise we just guess the approx temp based on dash gauge reading.

These are the values extracted from real tests (not only extrapolated from the curve):
---------------------------------------------------------------------------
Temp (degree F) -- Resistance (Ohms)
68 ----------------- 2600
86 ----------------- 1760
105 ----------------- 1200
122 ----------------- 876
158 ----------------- 454
176 ----------------- 330
185 - (Rad thermostat) - 295
194 ----------------- 260
212 ----------------- 190
221 - (fans activated temp) - 178

-------------------------------------------------
John (Montreal, CANADA)
K1200RS (2002 IceBlue/Red - 96,000 miles)
-------------------------------------------------
Think twice before you hit [SUBMIT REPLY] - famous quote by another member:
"The value of this board is not founded on dismissing the ideas of others, but by posting to share our experiences and what we've learned from them."

Last edited by sailor; May 19th, 2020 at 11:04 am.
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post #28 of 28 Old May 19th, 2020, 1:33 pm Thread Starter
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Location: Mobile, AL, USA
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Re: Idle speed increases while bike warms up

Quote:
Originally Posted by sailor View Post
Thanks for the update on the coolant sensor. DO NOT FORGET you still need to do a good check of resistance after the engine has been warned up to confirm resistance is in fact going down.

As per my previous instructions: you warm up engine, TAKE NOTE about where the engine temp on dash was, turn ignition OFF, unplug sensor, and do the static OHMS measurement again. If you have a very good "Infrared non-contact gun thermometer", you can aim it near where the sensor is plugged (rear-most cylinder head) to get a better approximation - otherwise we just guess the approx temp based on dash gauge reading.

These are the values extracted from real tests (not only extrapolated from the curve):
---------------------------------------------------------------------------
Temp (degree F) -- Resistance (Ohms)
68 ----------------- 2600
86 ----------------- 1760
105 ----------------- 1200
122 ----------------- 876
158 ----------------- 454
176 ----------------- 330
185 - (Rad thermostat) - 295
194 ----------------- 260
212 ----------------- 190
221 - (fans activated temp) - 178
Will do.

Ken

Ken Davis
Mobile, AL
2002 LT
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