I'm wondering if I'm experiencing the initial indications of a looming issue. During the cooler Northwest Florida winter months (low to mid 40F in the morning), upon initial startup (cold engine) my 2000 LT would immediately rev to approximately 1400 RPM and then settle to approximately 1200 RPM after a few seconds. Everything was good.

Now that the temperatures are warmer in the morning (mid 70F), the LT on initial startup (cold engine) will rev to approximately 800 RPM and not idle well until I give it a short twist of the throttle. Additionally, the battery warning light illuminates (the battery stays on a Battery Tender overnight). After I give the engine a shot of fuel from the throttle the RPM stabilizes at approximately 1200 RPM, the battery warning light extinguishes, and everything is good.

The low 800 RPM and battery warning light indications only occur during cold engine starts. I can make multiple engine starts after the engine has warmed without experiencing the indications.

Is there something I should inspect or I am making a mountain out of a mole hill?

Rob, 2000 LT
Navarre, FL

If you haven't done it yet. I would try a throttle position reset and see if it does the same thing.

I just replaced my TVA (idle actuator) because off and on it was getting to the point that I had to idle it with throttle manually until it warmed up a bit. Since I acquired it 4 years ago it has always idled at 1000 and if real hot sometimes 1200. With the latest intermittent problem it would not idle faster when I used reverse (sometimes)
I put the used TVA in yesterday and the motor idles rock solid at 900 so far. It also seems to start much better.

I was having strictly idleing problems, if yours continues to act up after previous suggestion changing TVA would be worth a try, it is a very reliable part

The alternator needs to get up to idling speed to start charging

Should the battery be disconnected, and for how long, before reconnecting and conducting the throttle position reset?

Rob, 2000 LT
Navarre, FL

With the key on twist the thorttle 2 to 3 times turn the key back to off then back on and start the bike up that should reset it

Disconnect/reconnect the battery for approx one minute before the reset

Or you can pull fuse F4. 15 minutes is more than enough.

The throttle position reset didn't work. In fact, the LT stalled during the first two cold start attempts. I gave it a touch of throttle and it idled unconfidently at approximately 900 RPM. Once warmed up after approximately 30-60 seconds it idled normally.

Looks like I have some research on the TVA.

Rob, 2000 LT
Navarre, FL

Okay guys, my looming issue has progressed to a no kidding problem and I need your diagnostic expertise. The initial cold start issue of the LT not wanting to idle without a squirt of fuel from the throttle has remained since I initially posted in June. The low idle issue still occurs only during cold starts (after sitting overnight or after a day at work). However, on the rare occasion she will crank and idle normally after a cold start without help from the throttle.

A second symptom occurred this weekend during a two day trip and I don't know if it is related to the cold start issue already mentioned. My calculated gas mileage dropped 10 MPG, the seat of the pants acceleration was nonexistent in that I had to gear down to pass when I normally wouldn't, and I noticed a slight change in the exhaust sound.

While riding, there was no "skip" during acceleration or at cruise, and the RPMs were rock solid. The outside air temperature varied from the upper 80s to low 90s.

Can the two issues be related? Is what I experienced with the drop in MPG and acceleration a sensor issue?

What do you guys think is my issue(s)?

Thanks,

Rob, 2000LT
Navarre, FL

Replace the fuel line and fuel filter in the gas tank or your clutch's slave cylinder is leaking into the clutch housing.

Get a GS911 onto it, and run the diagnostics tests.
Then get onto (ie, send a PM to....) Sailor... he is very good in these situations of working through each possible cause, but he really needs the diagnostic info. I've followed many of his threads (more on K12RS/GT's, but here too) and he is very methodical.

Charging / battery warning is a consequence of too low idling, but no cause for alarm as it is normal that it will be a bit low as alternator / charging system was designed for a normal idling of 900 to 1050 RPM. When the low idling problem is fixed, you should not see this warning light.

The low idling is not a big problem in general unless engine dies on you later during a ride when stopped at red lights or any other idling situation. It is annoying for sure - even if it happens only during initial start it should be investigated before things get worse (not sure they will, but just in case). My experience is that most of these "too low idle" situation are cause by either (in order of probability):
1) incorrect starting procedure: the throttle should always be closed at idle stop and should NOT be opened manually during starting phase (assuming the whole system is working correctly). I understand that now you need to keep it opened a bit AFTER start, but make sure you are not opening during start.

2) incorrect throttle cable free-play: specs / procedure to check is documented in CLYMER and on BMW shop manual. When there is not enough free play, it will confused the Motronic EFI system as what is the base reference at idle stop for TPS.

3) Defective or not well set TVA: the TVA is the idle-actuator that controls the fast idle when cold, and it also stabilized idle at all other times. This component has been very reliable, but there has been a few failure or bad behavior as it wears out (pretty mechanical device with a stepper motor and plastic worm-drive).

4) defective engine coolant temp sensor: this will confuse the Motronic-EFI system on cold start as it will use a default value of 80 celcius (176 F) when it sees any abnormal value after ignition ON. Failure are NOT common and when they fail you will often hear the radiator fans go on as soon as you turn ignition on (fail safe mode of the system)

5) Defective or not well set TPS: this component has also been very reliable in the past so unless someone did recent work around throttle-bodies, I would assume it is not the main cause.

OTHER CAUSES:
Obviously, there are other possible causes related to general state of tune of the engine. I am assuming here that the rest is in pretty good shape (air-filter, spark-plug, plug wires, valves checked). AS ALWAYS: many problems are related to recent work done on a vehicle - can you relate your problem to such an event?

Not sure I fully understand from above post of bike is running fine and has good pulling power in all other running conditions - does it ??
What about the fuel-mileage - do you keep track at every fill-up and is it still the same as before ??

----------------------------------------------------
UNLESS I can see the bike and take some measurements, the only way to troubleshoot AT A DISTANCE some of these sensors (item 3, 4 5) is to gather real-time data using a GS911.
PROCEDURE TO LOG DATA INTO A FILE from a GS911 (Yellow unit using USB-cable): There is so many variables from machine-to-machine that it is important for me to gather this data in same conditions to minimize variables.

(1) Install K1200LT on center stand (do not start until step 4 below)
(2) Plug GS911 into bike diagnostic plug, then into PC (if Yellow unit)

(3) Start software (will ask ignition ON) and go into menu "realtime values" + "Log to CSV" button. Use defaults for all items. Choose / type a filename or use the default filename offered.

(4) Start your K1200LT. AFTER about 1 minute of IDLING do occasional throttle twist to raise RPM to 2000 (4 to 5 seconds) and 4000 RPM (2-3 seconds). After these short RPM changes let it go back to idle for at least 30 secs in between. During the starting phase, open throtlle manually ONLY if you see engine will die.

(5) Stop "log-to file" on screen interface, then stop engine when you reach above half-way point on the temp gauge on dash -OR- at least a full log time of 4 minutes.

See attached image for menu items in GS911 software. Screen may vary a bit depending on your software version.

Attached Thumbnails

 

My LT does the low idle once in a blue moon. It doesn't cause an issue

Sorry, I mis-read your earlier post. I thought that you did have a 'skip' during acceleration. Yeah, it's possibly an O2 sensor issue or one of your spark plugs may have cracked. I had a crazy low oscillating idle with very bad gas mileage because one of my spark plugs had a hairline crack in the ceramic and the spark was jumping through the crack to the engine block. I could only spot it in a very dark garage.

Thanks for the response Sailor. Your posts are always informative and helpful to the community.

The cold start low idle issue with the bike dying is an annoyance, and sometimes embarrassing.

The LT will typically go to the normal idle RPM range on the second start attempt. As a note, the LT idled properly the last two mornings when the temperature showed 75F on the gauge. However, today after work when the temperature was showing 93F, it died on the initial start after a couple seconds of low idle. She idled normally on the second crank attempt. Once the LT is running, she idles within range. Your five suggestions as to the possible causes of the low idle have given me something to think about or at least speak to with some intelligence to a mechanic.

As for the "other causes" you mention, they are a possibility. The bike had a 24,000 mile service at 96,000 miles. It now has 111,000 and is 3,000 miles over the recommended 12,000 mile service interval. I was waiting for winter to perform the maintenance. The only mechanical work performed on the LT was the replacement of an ABS relay earlier in the year.

I am more concerned with the 20% reduction in miles per gallon and the reduced seat-of-the-pants acceleration. I am consistent with checking the fuel mileage. I understand your difficulty troubleshooting via a forum and with no data. If I had a GS-911, I would send you the file per your instructions.

In the meantime, I scheduled an appointment Friday with the local dealership with the intent of him diagnosing the issue with the Motoronic. I'll let you know the outcome.

Best,

Rob, 2000 LT
Navarre, FL

Thanks Chad. Your issue sounds similar to mine. Other than your reduction in fuel mileage, did your bike have any other symptoms?

Checking plugs is a good start and one I'm capable of performing.

Rob, 2000 LT
Navarre, FL

In general, the 20% reduction in fuel mileage is often associated / caused by a weak or defective O2 sensor. HOWEVER it is important to note that during a cold start (bike has been stopped for 8 hours or more) at any outside air-temperature, the O2 sensor data is NOT being used by Motronic during first 40 to 90 seconds depending how cold is the data coming from engine coolant temp sensor.

As an example, in a colder climate, when starting a cold engine at 50 F, the usage of O2 sensor signal will start after about 80 seconds of idling or a bit less if you do not wait too long to get on the road (this is often referred as engine being in "close-loop" mode for an EFI system, meaning the EFI system uses feedback loop from O2 sensor to adjust mixture). Until the O2 sensor has reached a certain temperature (located in exhaust), its signal is not reliable, hence EFI systems have a warm up time delay (plus a heating element built into the sensor to accelerate this process).

So, if your problem is mainly when started from cold, during first minute or so, then I would not put O2 sensor as the "most probable" item although it is easy for the dealer to check the O2 sensor signal in real-time while engine is running (or using a GS911).

Dealer should also check validity of engine-coolant sensor after the bike has sat for 8 hours or more AND also after engine is warm and hot.

Sometimes when leaning hard in a corner it would get really sluggish when trying to accelerate out. Also, the idle would fluctuate at stop lights....sometimes requiring that I give it a little throttle. Lastly, it did make a different sound from the exhaust.....I think it might have had a minor backfire during hard deceleration once (but I can't recall exactly).

I took the old girl to the dealership and the mechanic had answers to my low idle issue and reduction in fuel mileage/performance.

Low idle issue: The idle actuator required replacement and the throttle position sensor required adjustment.

Reduction in fuel mileage/performance: The mechanic brought me into the shop and pointed to the number two wire. It had been pinched by the cover plate. He had some concern with the number 4 plug. The compression test was within tolerance on all cylinders.

4 new spark plug wires, 4 new spark plugs, and an idle actuator are on the way ($450).

Now for the really good news (sarcasm), he shined his flashlight at the rear of the oil pan at the bell housing and it was moist with fluid. It is not wet enough to form a drip on the floor. He predicted the rear main seal was going. I could preemptively replace it or wait for the clutch to start slipping. I elected to wait as the clutch has 112,000 miles on it.

Rob, 2000LT
Navarre, FL

Most likely rear main seeping so the oil should not bother the clutch, if it is not slipping wait and watch

The mechanic said repairing the rear main seal and replacing the clutch would cost approximately $2000. I responded the cost was near the value of the bike. He pointed at the K1600s on the sales floor. A $2000 repair is a bargain!

Rob, 2000 LT
Navarre, FL

All is not lost!

You can drill a drain hole in the bottom of the clutch housing so you can see / smell (taste?) what kind of fluid comes out.....and how much.

Brake fluid means a failing clutch slave cylinder. That will need to be fixed, but the sticky at the top of the forum has a "video" by JZ
that will guide you through the repair.

Gear oil means transmission seal leak, & engine oil is probly the rear main.

Each has a distinctive smell.

If it's oil, and the leak isn't too bad, You should be able to ride for a couple years, providing the clutch isn't slipping (no urgent need to change a clutch that still works).