2010 R1200RT fueling problem / flat spot

[Nick900]

I everyone,

 

I bought a damaged 2010 RT that had been dropped on its right side. The face of the cylinder head had been scuffed during the fall so it was replaced with a used unit. The bike has covered 7K and the engineer who fitted the new head felt it had covered less than 7K miles due to the condition of the valves. I checked with the dealer and they confirmed the head was correct [part numbers also matched] and the valves were the same for RT's GS's etc.

 

I never rode the bike prior to the repair once the new head was fitted and again before riding I fitted a Remus end can and performance air filter.

 

Now the bike struggles to pick the revs up from 3-4K and from 5- up to the redline? This is my third RT although first twin cam. I am familiar with basic servicing and have balanced the throttle bodies several times, each time there being a good balance at 3K but everytime I test ride flat spots at the rev ranges above.

 

Idle is fine. A check on the plugs shows its not overfueling, if anything it appears quite lean [however I did clean the plugs thoroughly and they were quite clean to start with]. I have checked all coils and have a good spark.

 

Any ideas or is it 150 round trip to the dealer?

 

Regards

 

Nick

[dirtrider]

Morning Nick

 

Yes, lots of ideas but they are basically just guessing as there are many possibilities & we have little info on how the repair was carried out or bike's previous history.

 

First guess would be to do a TPS relearn (might be that simple) ***

 

Next on the list would an upper stick coil starting to fail (possibly on the repaired side). Just because you have spark while cranking doesn't mean that coil isn't breaking down & high RPM high engine loading.

 

Next would be a fuel delivery problem like a FPC starting to fail or fuel pump not able to deliver full flow & proper pressure.

 

Next would be things like a TPS failing or knocked out of adjustment or other engine sensor problem.

 

Possibly even a cam out of time or other engine issue.

 

 

***TPS reset procedure-----

 

*Disconnect the lead to the battery's positive post for 30 seconds.

Then

*Reconnect the positive lead to the battery's positive post.

Then

*Switch on the ignition.

Then

*Without starting the engine, fully open the throttle once or twice so that the control unit of the BMW engine management system can register the throttle-valve positions.

Then

*Switch off the ignition.

 

[Nick900]

Thanks Dirtider. Tried the TPS reset. The first time when I turned the ignition on there a was strange sound coming from the exhaust valve control unit. The only way I can describe is the warning sound when I car alarm battery is about to die. It was very muted and like a low resonnace. After when I restarted the idle was rough and it stalled a couple of times. Smoothed out a bit riding but riding but definately worse. Did a TBS and found from setting last night were way out. Reballanced and a little better. Did TPS again no strange noises. Checked balance and way out again? Reset to balanced took the bike out problem now has [at least at the lower rev range could not go full throttle as raining]. Seems to have shifted the problem to lower in the range. Now poor from 2.5-3.5K and fine above?

 

Anymore ideas I can try?

 

Thanks

 

Nick

[dirtrider]

Afternoon Nick

 

Usually when the TB balance keeps changing you have a problem with a throttle cable (or cable end) or you have a lower (Short) cable stretched too tightly over the air intake or something else. Make sure the lower cables are fully seated on both ends.

 

Check the lower cable ends that terminate at the TB's for being damaged or not installed properly. ( I have seen a few pulled apart & damaged)

 

Until you get your TB balance to stabilize or find the reason why it won't no sense in looking at other things.

 

Any chance you have an air leak in one of the intakes between a throttle body & cylinder head?

 

Might be an issue with one of the stepper motors also so check both of those.

 

[Nick900]

Thanks DT,

 

Will check now. What is the inspection process for the stepper motors? Also some one from another site suggested the likely cause is the k and n air filter and exhaust? Although I had a similar set up on my 07 model and it ran fine?

 

Thanks

 

Nick

[Nick900]

I have just checked the throttle balance and it seems stable now. Both throttle cables are seated fine and have the same amount of movement.

 

Regards

 

Nick

[Nick900]

I have tested all the plugs and coils both at idle and at about 3K revs. All seem fine. Spoke with the dealer who suggested putting stock air filter back in which I did this threw the throttle sync out. Rebalanced and did a TPS still have the same problem?

 

Dealer stated end can would have no effect and its also referenced on the BMW parts CD which just states fit the pipe and ride no further adjustment needed.

 

Still puzzled.

 

Nick

[dirtrider]

Afternoon Nick

 

If changing the air filter altered the TB balance then look closely that you have the right lower throttle cable routed over the air intake snorkel properly. Just changing the air filter should in no way effect the TB balance.

 

As for checking the coils, I'm not sure how you checked the coils at 3k but you really should swap in a known good set of coils as a test.

You need to eliminate the possibility of one of the coils being bad under load.

 

Otherwise check the cam timing & fuel pressure.

 

As a last test try disconnecting both 02 sensors then ride the bike. That will eliminate an 02 sensor issue as possibly your problem.

 

Otherwise get a GS-911 on the system & verify all the sensors including the TPS are operating properly.

 

[Nick900]

Hi DR,

 

Checked the coils by removing one coil at a time and putting a spare plug in the lead and testing the spark while increasing revs.

 

Will check the right cable now. Interestingly balance is out at idle with one side lower than the other. Even at 3K but out again at 5K

 

Thanks

 

Nick

[Nick900]

Just checked the throttle cables and no signs of any pinching both seem to have the same amount of movement each side. Will remove the O2 sensors tomorrow and try that.

 

Think it might be dealer only but they are 70 miles away and have no available slots until after 23rd.

 

Nick

[dirtrider]

Hi DR,

 

Checked the coils by removing one coil at a time and putting a spare plug in the lead and testing the spark while increasing revs.

 

---

 

Afternoon Nick

 

 

It takes way more KV & coil integrity to fire a spark plug under combustion load than with just with the plug hanging out in the open air.

 

About the only way you can check a coil at 3K with the plug just hanging out in the air is to open the spark plug gap to 3/16" or more.

 

Try this, take an old spark plug (doesn't have to be for your engine), open the electrode gap to 3/16" (use a 3/16" drill bit as a gap gauge). See if that will spark at 3k with a nice bluish colored snappy spark. If yellow, lazy or, intermittent then suspect that coil.

 

[Clievma]

Hi Nick,

 

I know you have checked the throttle cables but I've seen similar rough running problems when the throttle cables have been disturbed at the "Bowden" box (I think it's called). Both cables go into a box on the left hand side above the cylinder intake and tps. If the cables are unseated here this can cause issues with balance and rough running so worth double checking they both sit properly and are free to move/rotate.

Mike

[Nick900]

Took the bike to my local mechanic and he could not diagnose or improve on. Have booked in into a dealer on 24th will update everyone with the outcome.

 

Thanks

 

Nick

[racer7]

What DR told you about that plug gap to check coil output. Only other way is swapping with a known good part-- you'll get no where looking at plugs in air re checking output.

 

 

[Nick900]

Bike went into the dealer today. Was the first appointment available. Diagnostic came up with 23 faults, all which were reset. Tech would not ride the bike due to heavy rain! Order a replacement [used] set of coils and tried them still no joy so its not the coils!

 

Trying to describe it, there is a judder under full load at exactly 3000 rpms and it feels as though someone has cut the fuel off. Under low throttle it feels less abrupt and its more like a woolly feel. Above 5K it simply feels like fuel starvation. The bike is stripped at the moment and I will pull the plugs to see what they are like.

 

Any advice

 

Nick

[dirtrider]

Afternoon Nick

 

With the past history of that bike & the fact you didn't ride it before installing the cyl head or exhaust system there isn't much to say except you will probably need to go over EVERYTHING that could have any effect on your problem.

 

If the dealer didn't find any smoking gun (though it sounds like they sure didn't put much effort into it) it probably isn't something loose or out of adjustment.

 

I guess if it were my bike I would---

 

Check the cam timing on the dropped side head.

 

Check the fuel pressure & maybe jump the fuel pump to full power (by-pass the FPC) to see what you have there.

 

Look for a pinched fuel line.

 

Re-install the original exhaust (maybe you are fighting a reversion issue)

 

Ride it with both 02 sensors disconnected.

 

Verify the knock sensors are functioning.

 

Look for a nice spray pattern from both fuel injectors.

 

Verify anything else that could effect your problem.

 

[Nick900]

Thanks DR,

 

Just checked the plugs having driven 2K since the damage. Nothing obvioous. Cores look fine outer rim a little sooty. Will go for a ride with the O2 sensors disconnected tomorrow. I know the cam timing is fine and it was checked just after the head was fitted given the rough running. Checked fuel lines again and they are fine. Could you advise of a way of testing the knock senors and there location?

 

Thanks

 

Nick

[dirtrider]

 

Morning Nick

 

Knock sensors are on rear of cylinders (see pix)

 

As far as testing, good question. Without a GS-911 or dealer computer you are probably limited to just disconnecting both & riding the bike.

 

[Nick900]

Hi Dr,

 

Thanks. I think there is progress! Disconnecting the right side knock sensor is the only thing thus far that has improved things. In 1st and 2nd gears under heaving acceleration the hesitancy and flat spot are virtually undetectable. In third under full load is noticeable but much less and ends sooner.

 

Would you suggest buying another and simply replacing? I am about to invest in a GS911 and did buy one a few weeks ago from a UK website then found my money had been re-routed to China and had to wait for it to arrive and inspect before coming it was a fake and returning it!

[dirtrider]

Morning Nick

 

Disconnecting that sensor is probably telling you that you either have a bad sensor or the sensor is reporting a knock.

 

SO, try swapping the sensors side to side, then if disconnecting the damaged side still improves the problem you probably have a combustion knocking issue.

 

If when disconnecting the other side the problem gets better then the problem went with the sensor move.

 

[David R]

I managed to get a cam sprocket on the shaft wrong and squish the little tab that lines it up. Bike ran like crap. I check the last thing I had woked on and sure enough it was it. All APPEARED TO BE CORRECT but it was not. Seemed to run on one cylinder better than the other especially at different work loads and RPM.

 

I think DR nailed it in post # 808914.

 

Go over everything. It could be something obvious or something you are sure is right, or something quite silly once you find it.

 

Knock sensors can be checked with an Oscilloscope. Not a lot of people have them. I found it easier than having a scanner for everything. It will also show glitches in the TPS, coil misfires if hooked up properly, o2 sensor output, fuel injector pulse width....

 

 

Best of luck.

 

David

[dirtrider]

Evening Nick

 

If that knock sensor doesn't pan out I had another thought.

 

Kind of a long shot (real long shot) but something to verify.

 

The lower spark plugs are not sparked at the same timing as the upper plugs as the RPM increases (called a phase shift). At low RPM's they spark at the same time but as the RPMs increase the lowers are phase shifted so far from TDC they effectively do nothing.

 

Not sure if it is even possible but if the upper & lower wires going to the coils were somehow swapped with the lower wire harness going to the upper plug that would pretty well deaden that cylinder at higher RPM under load but could still run good at lower RPMs.

 

Unfortunately I don't have the wire colors for the 2010RT coil harness wires to give to you. I'm not even sure it is possible to hook those up incorrectly so this is just a thought.

 

[Nick900]

Thanks Everyone,

 

Turned out not to be the knock sensors so back to square one. I swapped them over tried them connected / disconnected but could not repeat the slightly improved acceleration. It could be the sprocket alignment I am not skilled enough to check this and the mech who fitted the new cylinder head on informing him of the terrible running removed everything and checked his work. While he's not a BMW specialist I chose him having listened to him having already replaced a clutch on an RT making me think he was able. Its booked into the dealer again next week but I am not confident.

 

Do wish I had access to an oscilloscope but I don't.

 

Nick

[dirtrider]

Evening Nick

 

Seeing as one side cylinder is exactly 360° different than the other side if you make up a simple 360° degree wheel (find a downloadable one on the internet) then glue it to a circle of cardboard & hot glue it to your front crankshaft pulley.

 

Now make a pointer from a piece of wire or coat hanger & attach that so it points to the degree area on the degree wheel. (in actually it doesn't even have to line up with 0 at TDC).

 

Now (upper spark plugs removed) rotate the engine in the running direction & note where the GOOD SIDE intake valves open & close & where the EXHAUST valves open & close.

 

Now do the same for the replaced head side.

 

If the valves open & close at about the same timing then your cams are timed correctly. If way different then go looking for the reason.

 

In fact you don't even need a degree wheel for a quick test as you can just mark the front pulley to engine block as the intakes just start to open on the good side then check the new head side against that mark, then do the same for the exhaust.

 

[Nick900]

Hi Dr,

 

I have not had time to check the timing but have bought a GS911. It arrived today and used it for the first time hoping for positive results or diagnosis. On first scan it came up with several old faults. I cleared those went for a 10 minute drive and re-scaned, there were no new faults! Have gone through as many of the options I can see in the various menus and tried resetting everything but its still present and don't seem to be getting any further.

 

Thanks

 

Nick

[Nick900]

Now starting to get more into the logging function. On starting Lambda sensor values were initially in the low end of lean. Then after about 5 mins they were swinging wildly from below lean to above rich. This was during the plot. In the log in value screen Lambda sensors kept going on and off, not sure if this is normal?

 

Nick

[dirtrider]

Afternoon Nick

 

Yep, pretty normal.

 

At cold start & before the 02's get hot enough to react the BMS-K places a constant voltage on the 02 output so it can tell when the 02's are starting to work & react to oxygen.

 

Once the 02's are up to temp & working then normal 02 output would be continually cycling low/high/low/high/etc across the center.

 

This cycling is needed to keep the cat. supplied with enough oxygen to operate properly.

 

[Nick900]

Evening DR,

 

Is there anything else you could suggest I check or look at the values?

 

Thanks

 

Nick

[dirtrider]

Evening Nick

 

Not really unless you can trap the data when it is flattening out.

 

One thing you might check is to verify one side against the other on anything that has separate side inputs.

 

I forgot this in an earlier posting -- do both side front exhaust pipes look to be about the same color about 4"-6" from the cyl head?

 

If you can come up with or borrow a couple of somewhat matched vacuum gauges you might hook one to each side TB nipple then compare manifold vacuum when it is flattening out (that might show a cam timing issue).

 

[Nick900]

The bike has been at the dealers for 3 days now and the costs are mounting. They still have no idea what is causing the problem. Nothing shows up on their diagnostic. They have tried;

 

All coils

Checking timing and value clearances

Throttle pot

Fuel pump

Fuel tank for water

Fuel lines

 

They are now saying its a case of just swapping things at random with not much hope they will get the right thing! The only positive being that its not an intermitent fault. Tech states after every change the minute he's driven 50 yards he can tell still nothing above 3K. The only thing he seems to state is it feels more like a fueling problem.

 

Nick

[dirtrider]

Afternoon Nick

 

I hate to see "parts swappers" but sometimes it comes down to that if nothing shows on the test instruments.

 

As long as they aren't charging your for the parts that didn't repair it then it could be a legitimate procedure.

 

Maybe have them run an exhaust backpressure test or try swapping the exhaust systems. If you have a partially plugged exhaust, (or cat), or a malfunctioning flapper valve that could kill off the 3K + range. A plugging exhaust can feel a lot like a fueling issue.

 

[Nick900]

I should have added the tech did comment the exhaust valve was heavily coated in unburnt fuel. So it would seem the fuel is going in okay but the signal to the coil to ingite is not present?

 

Also noted on loan bike with my riding style got 48mpg on my bike will only return 36!

[dirtrider]

Afternoon Nick

 

 

A plugging or restrictive exhaust can show signs of incomplete combustion & unburnt fuel. (you end up with a lot of EGR effect from high exhaust pressure)

 

If your bike runs OK at lower RPMs but only acts up at 3k + I doubt your would have much unburnt fuel showing on the valves (it would burn off as the RPMs come down through the good operating range.

 

[Nick900]

Hi DR,

 

The evidence of overfueling was noted on the exhaust flap.

 

Thanks

 

Nick

[dirtrider]

Afternoon Nick

 

What did they find on your cam timing?

 

[Nick900]

Hi Dr,

 

They said it was out slightly but could not advise of how many degrees only that their alignment device would not fit with the cam timing as it was set. However they adjusted it but still made no difference.

 

Thanks

 

Nick

[roger 04 rt]

Hi Dr,

 

I have not had time to check the timing but have bought a GS911. It arrived today and used it for the first time hoping for positive results or diagnosis. On first scan it came up with several old faults. I cleared those went for a 10 minute drive and re-scaned, there were no new faults! Have gone through as many of the options I can see in the various menus and tried resetting everything but its still present and don't seem to be getting any further.

 

Thanks

 

Nick

 

I see that you are still working on this. The GS-911 has a logging function that can log all realtime values to a .CSV file if you have a notebook connected. I do this a lot.

 

The idea is connect the GS-911, set up logging to a file with your PC attached then go for a half hour ride. Then stop logging, save the file, and import it to excel for analysis and plotting. Lots of stuff shows up. I'd be happy to look at the data.

 

This may help to diagnose the problem. Now if you also had twin LC-1s you would have a pretty great diagnostic setup but that's another story.

[Hall Vince]

So, any news, must have been fixed by now or is it a pile of molten metal and ashes?