Stuttering/Hesitation on Acceleration

[tcausey]

I have an 02 R1150RT and I'm noticing what seems to be an occasional problem that I'd love some advice on.

 

Not all the time, but sometimes, when I'm at idle and I start to accelerate, I get a little hesitation until I get moving good. When I get OCD and just "blip" the throttle in idle as a test, it stumbles like it isn't getting enough gas or something. Again, it's not constant . . . sometimes there is no problem and others there is.

 

side note: a couple of times in the last 2 or 3 months, I've had the bike stumble and die after a quick ride home (10 mins or so) as I come off the interstate to a stop. After a minute or so, the bike starts back up and keeps going. I mention it in case it's helpful.

 

Again, it's mostly annoying, but if it's a sign of a larger problem, I'd love to get my head around it so any help is very much appreciated.

 

Troy

[roger 04 rt]

I think you'll get a lot of ideas but you need to fill in some gaps. How many miles, when did it last get plugs, air and fuel filters, valve adjust, TB Sync and so forth? Are you running a stock config, what fueling enhancements (BoosterPlug, Techlusion, etc.) the better the picture we see, the more good ideas you'll get.

RB

[Quinn]

From my level of ignorance, I'd try a couple of tankfuls with Seafoam or other injector cleaner in it. You might also consider sta-bil or other gas drier if it's just water in the gas tank. After that, I'd want more symtoms. Bike hot or not? full tank or empty? Stick coils resistance check out when happening? If you open the gas cap, do you get a rush on air from suction? How do the plugs look?

 

Now more competent people will chime in with good advise.

 

----

 

 

[tcausey]

more facts:

47k

plugs, TBS, valve adjust in April 2012

fuel filter: April 2011

air filter: April 2012 I think

Config: I've run several and this occasional hesitation problem persists to some degree with all

-now: Stock pink CCP with IICE Air (similar to booster plug)

-before: Olive green (jumper) CCP with stock air temp sensor

-before that: Stock

 

Plugs have always looked good (i change them about once per year normally whether NGK or Autolites.

 

I've done seafoam a little over time. I haven't considered fuel level until yesterday and it was at about half a tank.

[roger 04 rt]

That is all very helpful and gives a much better picture of what's happening. I've read about and discussed this with several single-spark 1150 owners who've reported the same. It sounds like your bike doesn't like running at 14.7:1 (lean).

 

You can test that by letting the bike get stone cold, starting and immediately driving off. During the first couple minutes (that's all the time you have) and before 1 bar on the RID, there is fuel enrichment. Does it drive better during this period?

 

If you get good wide-open throttle performance, I think you can rule out fuel pump/filter/internal-tank-hoses for the time being.

 

The two other parts that effect your operation are your O2 sensor and fuel injectors.

 

Your fuel injectors could be clogged or imbalanced. Mine were to a degree even after Techron Concentrate. The only way you can find out is to send them to a reputable shop.

 

Your O2 sensor could be old and sluggish. The only easy way to tell if this is your problem is to replace it.

 

The other thing you could try is unplug your O2, reset your Motronic and relearn the TPS, and try riding with your IIce Air (which I've had and have measured) in the -10C, then the -20C and then the -30C position. Let us know how that goes. Contrary to what Poolside says, make sure you put your IIce Air in a place where it gets very good airflow, ideally right near where the forward tube interfaces with the intake tube on the left side. When the IIce Air is in any position other than 0C, the IAT sensor in your intake manifold is completely disconnected.

 

RB

[dirtrider]

Morning Troy

 

Your problem could be one or more of many things so about your only recourse is to try different things.

 

A GS-911 could help you identify your issue if engine sensor related but if mechanical or fuel related maybe not directly.

 

The first thing that comes to mind on your issue is your TPS has a worn spot just off idle & is not tracking smoothly.--To MAYBE catch this try hooking up an analog (needle type) voltmeter between terminals 1 & 4 on your TPS (leave the stock wire harness plugged in & the key on) then smoothly open & close your throttle a few times while watching for the needle on the voltmeter to SMOOTHLY follow the throttle movement. If you see a dip or non linear needle movement you possibly have a bad TPS. Do this both on a hot engine & cold engine. Do not use a digital voltmeter as most of those are too slow & use averaging so probably won't show an issue.

 

If the TPS checks out OK

 

Check you fuel pressure & if possible your fuel flow quantity. Low fuel pressure can cause an issue like you are seeing. Or just see if your bike will maintain top speed of 125mph+ for a mile or so. Or if you are squeamish about doing a top speed run out test just find a long steep hill & climb that in a higher gear than normal at wide open throttle looking for signs of fuel starvation.

 

 

If still nothing found

 

Remove the R/H tupperware & verify your 02 sensor wiring is not routed along or near your R/H spark plug wire. Cross talk between your R/H plug wire & 02 sensor harness can cause all kinds of throttled up issues. This problem is prevalent on the 1150 twin spark engines but on your single spark someone would have had to manually route it there at one time.

 

If nothing found in the 02 sensor harness routing

Then as Roger said, try disconnecting your 02 sensor then clearing the adaptives in your Motronioc (remove #5 fuse for 30 seconds) then do a new TPS relearn. Now ride the bike & see if your problem goes away. If so you might have a lazy or malfunctioning 02 sensor.

 

If still no problem found try disconnecting the evap system hoses from the bottom of the TB's the plugging the TB fittings off with rubber plugs or short pieces or hose with a golf tee or screw in the hose. If this helps your problem then you probably have a fuel logged evap system & your TB's are taking in a slug of raw fuel as the evap solenoid opens.

 

On your 2002 single spark 1150 by far the best CCP to use is the stock pink one so stick with that until you find & eliminate your stumble issue.

 

Other things to check is that the little ground wire is hooked up & making good contact to the L/H TB bottom.

 

That the wire connector on your oil temp sensor (top of oil thermostat) is plugged ALL THE WAY IN. If possible put a GS 911 on the system & verify your oil temp sensor is working & that the Motronic is seeing that input properly.

 

Bottom line-- (IF) your bike runs good at high speed high road load it probably has decent fuel flow at enough pressure & a good enough spark to light it off. So that probably leaves light throttle fueling as your issue. The main players here are TPS, fueling adaptives based on 02 sensor input, or excess fueling from the evap system. So, check those things out first. Also be sure you have the proper CCP installed during the tests.

 

One last thought, if you have an aftermarket (open) muffler & no cat converter on that bike you might be fighting an exhaust reversion issue. If so let us know as there are ways of helping that somewhat. Exhaust reversion can be a real issue on certain bikes.

 

[tcausey]

Thank you. I have a fair bit to do for diagnosis then. One more fact. The bike has become slightly harder to start in the last few months. It always starts, but it takes a couple of times. Odyssey battery a couple of years old so it's not that I'm fairly certain. If that helps pinpoint something more likely to start with, let me know, otherwise, I'll report back when I can. Thank you again.

[dirtrider]

Morning Troy

 

That could be pointing to an errant or out of spec engine sensor or, maybe due to your intake air spoofer driving the system to disregard the intake air temp input.

 

I'm not sure on the BMW Ma 2.4 system but a lot of automotive systems use a matching (or close anyhow) engine temp & intake air temp to tell the system it is a TRUE cold engine start & not just a cold ambient warm engine start.

 

So try disconnecting your Intake Air Spoofer & running with the stock IAT until you get your bike back operating like it should.

 

If at all possible get a GS-911 on your system to verify all system sensors are operating within their nominal specs.

 

Things like low fuel pressure, errant TPS input, errant engine sensor input, really strange Motronic adaptives, etc, can cause difficult starting as well as your hesitation issue.

 

[roger 04 rt]

Morning DR,

 

The MA 2.4 doesn't seem to cross check Oil Temp and Air Temp. I've got tons of data and regularly check my Motronic faults.

 

However, I've noticed several times that connecting the IAT connector to a BoosterPlug or IIce Air will sometimes result in the Motronic not seeing the sensor--and reporting a temperature of 20C. I can tell this because I often have the GS-911 connected but without one, you'd never know that it had happened. The solution is to slide the sensor connector apart and together a couple times.

 

RB

[dirtrider]

Morning Roger

 

I'm not saying it will give a fault just (possibly) change the fueling algorithm from cold engine long (like overnight) cold soak to partially warm engine cold ambient.

 

On cars there are possible scenarios that would allow cool engine temp sensor, cold Intake Air but still somewhat warm internal engine block & cylinder heads at start up. A matching IAT & engine temp would tell the system that it is indeed a very long cold soak start up.

 

On the system not recognizing the Booster Plug-- On the Ma 2.4 system I really don't know but again on a lot of cars & light trucks if the intake air input is really out of nominal ranges it will allow the PCM to assume a bad sensor & assign a nominal (usually around 70°f) temp input assuming a bad sensor. This is to keep the system from over fueling due to a bad sensor.

 

When I have played with spoofing the intake air temp I always add a simple in line switch so I can go back to stock IAT for very cold starting as over fueling at cold start up is a good way to wash cylinder walls and/or add raw fuel to the engine oil.

 

[tcausey]

Thanks DR.

 

The air intake spoofer has had no affect on the starting issues at all. I might not even call them issues, but just not a first try startup. I've only had the spoofer on for a few days. It's made a fairly significant impact on acceleration and fuel starvation on massive acceleration (come to think of it, I have done that test on higher than normal gear, uphill and it's always had fuel starvation symptoms that I thought were odd, but figured was normal). Spoofer fixed that.

 

Air intake temp and oil intake temps are independent as I understand it (which is why Poolside is working on the IIce Cool (for the independent oil intake temp spoof)

 

Makes sense to go back to stock Pink and no IAT spoof to debug however. I will say that the 30-86 jumper impacts the surging problem (as does TBS, Valves, etc.)

[dirtrider]

Afternoon Troy

 

Be very careful in your evaluation of your surging issue. It's easy to get misled & think you have effected the surging when it is just riding circumstances or perceived.

 

In most cases (about all that I have seen) 1150 single spark surging cases happens at light throttle in closed loop operation. In closed loop things like CCP changes, 30-86 CCP jumper, IAT spoofers have no (long term) effect.

 

In closed loop the only real fueling control is the o2 sensor (closed loop means ONLY between the o2 sensor & the fueling computer). Things like IAT spoofers, & oil (engine temp) sensor spoofers, & CCP's can slightly effect the dynamic spark control but not the closed loop fuel air ratio as that is ONLY controlled by the o2 sensor when in closed loop operation.

 

Now on the 1150 Ma 2.4 system if you ride with the o2 sensor disconnected that FORCES full time open loop operation so things like Intake Air Temp spoofers can have some effect on the fueling in open loop operation.

 

At heavy throttle up the system does go open loop after a short time so you can slightly effect the power there but that isn't usually a surging operating range.

 

The way you say you think you have lean fueling under load might lead to low fuel pressure, or lazy fuel injectors, or engine sensor issues.

 

Just for general information I haven't EVER seen an early single spark BMW 1150RT that didn't surge in (stock) closed loop operation at light steady throttle. Some riders claim theirs doesn't but every one that I have ridden even with that claim attached I could easily get to surge.

 

If you want to eliminate the 1150RT lean surging you either need to run it open loop then add fuel with an IAT spoofer, or Techlusion, or some type of sensor spoofer.

 

If you want retain the closed loop operation & reduce remove/surging you will either need to add a 2nd set of lower spark plugs (like the twin spark). Or see Rogers LC-1 set up to use a wide band o2 sensor & tuner, or add something like the Techlusion fuel controller & spend the time tuning it.

 

Bottom line here is: as long as the stock narrow band o2 sensor is active & the fueling computer is fueling to that input (steady throttle closed loop) no matter what you do externally to effect the fueling or add additional fuel the o2 sensor will quickly force the fueling computer to just remove it through injector pulse width control.

 

[tcausey]

Thanks DR. The surging for me is manageable as it's always occuring in the same throttle range for me.

 

thanks again.

[tallman]

"Be very careful in your evaluation of your surging issue. It's easy to get misled & think you have effected the surging when it is just riding circumstances or perceived."

 

My first thought.

[4wheeldog]

Looking for the simplest possible explanation.....I have the same model and year as yours. At one point around 40k miles, I had the same symptoms as you report. When it got bad enough, I found that I had about a quart of water in the bottom of my tank. I also found that the drain from the outside of the seal around the gas cap was plugged, so that everytime I opened the cap when it had rained, I was dropping an ounce or so of water into the tank.

 

I used a piece of 1/4" tubing to drain the bottom of the tank into a clear vessel, so that the separation of water and fuel was apparent. And I unplugged the drain. Things have worked fine ever since, about 8 years. Good Luck.

[tcausey]

I have replaced the o2 sensor and the most immediate change is that it's much easier to start. It also runs considerably better in closed loop operation right after starting.

 

more in time. thanks again.

 

[Sidmariner]

I know exactly what you're talking about and it is something entirely different from the surging issue in my mind. I've got a Techlusion unit and virtually no surging issue, but I sure do have a stubborn mule issue when starting up.

 

Last week, on a four day road trip during a minor heat wave, my '02 starting behaving as you described almost every time I tried to get going. It was embarrisingly obvious when I was the Beemer in a bunch of bikes trying to get off a local ferry. My bike was the one coughing and bucking and threatening to quit unless I clutched in and blipped the throttle. Once rolling on the road at speed it behaved nicely as always.

 

Somewhere in this forum I read that the culprit might be a plugged charcoal cannister causing some kind of vapour lock or charcoal contamination. The advice to remove it was pretty convincing, so I plan to do a "canorectomy" this weekend.

 

If your can is already gone this won't help, but it might be useful to others.

[kmac]

I am starting to feel like it is just one of those "character" things.

My '96 RT with 26k and a complete tune 2 months ago still surges, pops, stalls on take off and on decell all randomly and just once in a while.

 

I also like you have new:

plugs

AF

OIL

OF

O2 sensor

TB sync by reputable dealership

Idle and all cables adjusted (throttle and choke)

valve adjust

 

Yet still the same old pop at rev up occasionally and once in a while stalls.

Also stalls when you are running at a constant throttle and pull in the clutch and let the rpms just drop off....once in a while dash lights come on, motor dead.

 

Really irritating. Pushing me towards a Guzzi or a Tenere lately.

 

 

[Bologna]

Techlusion, TB sync, plugs perfect, non oxy fuel and I too get a ping/knock at certain rpm more often in warmer weather.

Run some Techron and enjoy the ride!

 

[roger 04 rt]

After reading all the posts in this thread I've got to comment.

 

It may be lame to say this, but after my long Wideband O2 project it seems to me that an Oilhead engine can be made very smooth. The Motronic's not that complex and the boxer engine isn't that unique. The pieces of the engine system and fuel injection need to be functional, adjusted and clean ... And some models need a slightly richer mixture than realized by the stock narrowband O2. Living with the (often) minor issues is a valid approach but not the only one. The engine doesn't need to be driven at high RPMs and when well tuned it pulls from idle to red line and is strong from 2000 on up.

[Sidmariner]

I agree...and my bike is a pampered and smooth running machine, except lately it sounds like a chain smoker getting up in the morning. It seems to need to clear its lungs for a minute before it can get on with the day. Once running, it will purr along for hours. Start it up after a break and it will hork and complain until you kick it up to speed again...very curious.

[kmac]

After reading all the posts in this thread I've got to comment.

 

It may be lame to say this, but after my long Wideband O2 project it seems to me that an Oilhead engine can be made very smooth. The Motronic's not that complex and the boxer engine isn't that unique. The pieces of the engine system and fuel injection need to be functional, adjusted and clean ... And some models need a slightly richer mixture than realized by the stock narrowband O2. Living with the (often) minor issues is a valid approach but not the only one. The engine doesn't need to be driven at high RPMs and when well tuned it pulls from idle to red line and is strong from 2000 on up.

 

My bike has had ALL of the components completey cleaned at SD BMW, injectors, BBS, TBs, all of the parts are fresh and clean and dialed in by a factory trained service tech and it still runs like a Mac truck, not the awesome power and torque of a mac truck, more the clunky clattery chugging side of the Mac truck. I do not know what else to do. Accept the high rpm stalling at throttle closing and surgy idle that pops and stalls at times leaving me stuck in an intersection at a green light ready to get mowed down from behind and just call it "Character"?

 

To say it just needs so part and some cleaning and adjusting is not doing it for me. I like 80% of the bike alot, but that irritating 20% could be deadly, not sure I like that part at all.

 

What are you saying is the fix? Just a braodband O2 sensor and I will have smoothness and power?

[roger 04 rt]

After reading all the posts in this thread I've got to comment.

 

It may be lame to say this, but after my long Wideband O2 project it seems to me that an Oilhead engine can be made very smooth. The Motronic's not that complex and the boxer engine isn't that unique. The pieces of the engine system and fuel injection need to be functional, adjusted and clean ... And some models need a slightly richer mixture than realized by the stock narrowband O2. Living with the (often) minor issues is a valid approach but not the only one. The engine doesn't need to be driven at high RPMs and when well tuned it pulls from idle to red line and is strong from 2000 on up.

 

My bike has had ALL of the components completey cleaned at SD BMW, injectors, BBS, TBs, all of the parts are fresh and clean and dialed in by a factory trained service tech and it still runs like a Mac truck, not the awesome power and torque of a mac truck, more the clunky clattery chugging side of the Mac truck. I do not know what else to do. Accept the high rpm stalling at throttle closing and surgy idle that pops and stalls at times leaving me stuck in an intersection at a green light ready to get mowed down from behind and just call it "Character"?

 

To say it just needs so part and some cleaning and adjusting is not doing it for me. I like 80% of the bike alot, but that irritating 20% could be deadly, not sure I like that part at all.

 

What are you saying is the fix? Just a braodband O2 sensor and I will have smoothness and power?

 

What I'm saying is I see no reason why your R1100RT can't run really well with good pull from idle to red-line. Your maintenance person just hasn't figured it out; and it's not that easy for him/her (or an approved procedure) to experiment with mixture.

 

It seems from the many, many posts on the subject of surging that a lot of bikes would benefit from a richer mixture--the very mixture that BMW selected when they shipped the early Oilheads to Europe. That configuration was: 1) No Catalytic Converter; 2) No Closed Loop; and Mixture about 14:1 (or Lambda = 0.95).

 

Since it seems that you've tackled everything else, if yours were my bike, I would look at the effect of mixture on performance. (You might also want to check fuel pressure and volume which can also affect mixture if it is grossly wrong.) I've cut-and-pasted a comment I just wrote on another board, in italics.

 

You're right, it is easier to move the 1100 series to a richer mixture (a mixture less than lambda = 1). That capability is built in to the Motronic MA 2.2. And you're right that it is accessed by removing the Coding Plug (on the R1100RT, for the GS you should keep pin 87a jumpered). Lack of a coding plug tells the Motronic MA 2.2 that there is no Catalytic Converter, and that it should look for a CO potentiometer (used to control idle mixture for carbon monoxide content).

 

Based on the CO adjustment target of 1.5%, I'm of the opinion that the fuel map accessed by no-Coding Plug has a cruise AFR of 14:1 (my 1150RT runs very well at that AFR). This is a setting of lambda = 0.95.

 

However, the throw-away-the-coding-plug doesn't do that much if you run E10 gasoline. The no-Coding Plug fueling table, while running E10 produces a mixture of lambda = 0.99. Since Closed Loop with the plug is lambda =1, you are no better off, and in fact if your injectors are on the low side of normal, or your fuel pressure is low, you would be worse off from the standpoint of mixture.

If you run E10 on an R1100RT, I would remove the Coding Plug and add a BoosterPlug. That will get your mixture to lambda = 0.94.

 

There is an even easier test to see if mixture effects your bike and it works on any 1100 or 1150. Let it cool overnight (the colder the day the better since you get more riding time). Then start it and ride it in the problem RPMs until you see 1 bar on the RID temperature display. During that time the Motronic is: 1) Open Loop, meaning the O2 sensor is not being used; 2) Enriched by several percent. If the bike doesn't run better at this point, you can reset the Motronic, add a BoosterPlug and run this cold test again. This erases any Adaptive Values that may be skewing the mixture.

 

If any of these tests makes things better, you can stay as you are or add an Innovate Motorsports LC-1 to permanently shift Lambda.

 

(For anyone who wishes to borrow a BoosterPlug for this experiment, I have a loaner that is a cosmetic "second".)

[ElevenFifty]

Read about your woes in the "DR" thread. My '04 RT has been a mechanical wonder but like all machines needs some TLC. The past couple of days I've been working on a throttle body rebuild and yesterday managed to reproduce your symptoms.

Hard starting

Popping that has just never happened on this bike

Ran good at speed - though not as smooth as I'd like

Hesitation and stumbling at idle ... died at a stop sign

 

The only difference is that my symptoms were not intermittent so much easier to diagnose and fix. Turned out that the stop on the throttle body was set just a hair too high ... the butterfly was not closing completely causing too lean mixture at idle ... purely mechanical.

 

I could imagine that a little bit of a 'gummed up' TB pulley or shaft might stick if the throttle were 'rolled off' easily but would close completely if the throttle were chopped. This would create an intermittent set of symptoms.

 

Try this ... the next time it is 'hard to start' and you can get it into the stumbling, hesitation prone idle, try closing one of the big brass screws on one of the throttle bodies. If the idle gets worse - that's a good sign. Try the other side. If one of the screws has no effect on the idle when screwed all the way in, then your butterfly is stuck slightly open.

 

Wild a$$ guess, I know - but worth a look.