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2006 RT hesitation trouble


rottyjohn

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Hello All,

 

I have a 2006 1200rt with almost 70,000 miles on it.

 

All of a sudden I am getting a hesitation and sputtering at 4000 rpm during heavy acceleration. No issues with starting, the idle I would say is OK but maybe a tiny bit rough? Normal operation below 4000 rpm. I am normally in 5 or 6 gear when hesitation occurs trying to accelerate from just below 4K. Revving with no load from idle seems absolutely normal? Did a bunch of reading posts. Seems like most point to stick coils?

 

To start trouble shooting. Hooked up 911 no codes. Checked throttle sync with twin max its dead on. Valves are well with in specs. I choose to pull all my coils out next and ohm them out. Haynes book says primary circuit should be .78 Ohm and secondary circuit 6 Ohms. Is this right? All checked the same very close to the .78 but 31 Ohms for the secondary? All coils were made in 05 but really no external signs of damage? no cracks swelling etc? Insane what they cost if this isn't my trouble. Ugh!

 

Sure would appreciate any thoughts or similar issues,

thanks ,

John

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Afternoon John

 

At first guess it does sort of point to stick coils (uppers usually).

 

You really can't tell much on the BMW stick coils with an ohmmeter as the primary side seldom if ever fails & when that side does fail it is usually a complete coil quit.

 

The secondary side is not fully connected back through the coil connector so about all you can measure there is built in RFI protection.

 

As a rule when stick coils fail they start arcing internally & no way to measure that with an ohmmeter.

 

Your problem might be as simple as a spark plug breaking up under high RPM load so new (or trusted good used) spark plugs are probably the place to start your troubleshooting. (at 4K up it is usually upper plugs as the lowers are pretty well phased out at that RPM)

 

Substituting new (or known good) stick coils is also a good solid place to start.

 

Other things to look for is a fuel flow problem (possibly a failing FPC)

 

Or even one of your knock sensors acting up. There is an old BMW service bulletin on a flat spot at higher RPMs due to knock sensor calibration & lower octane fuel so IF your problem just showed up maybe run the tank down near empty & re-fill with the highest octane fuel you can find.

 

 

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Thanks DR for the quick response,

 

I do remember reading an older post of yours talking about FPC. New vs old. I actually still have the older version with the heat sink like fins. I have been carrying a bypass cable with me figuring not to mess with it until it went out? I was under impression it would just not start if controller went bad. It does make sense to me if a bad controller is limiting voltage to the pump at a peak time. I suppose could test it by plugging the bypass cable in and see if it helps? Guess maybe it might just time to get the newer style?

 

I will first throw some new plugs in and see if its as simple as that, boy that would be sweet? I did just change them though less than 3000 miles ago. Normally change them every 12K and clean them when I adjust valves. They always look really good to me.

 

Thanks for the suggestions.

 

John

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I had the same problem a few years ago. It was a primary stick coil. A friend has a GS and he let me borrow one of his coils. I changed the right side coil and the problem was still there. I changed the left side coil and it ran perfect again. Bought a new primary coil and I was good.

 

 

Roger L

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All of a sudden I am getting a hesitation and sputtering at 4000 rpm during heavy acceleration. No issues with starting, the idle I would say is OK but maybe a tiny bit rough? Normal operation below 4000 rpm. I am normally in 5 or 6 gear when hesitation occurs trying to accelerate from just below 4K. Revving with no load from idle seems absolutely normal? Did a bunch of reading posts. Seems like most point to stick coils?

 

Exact symptoms I had last summer immediately after gassing up at a run-down station in a small town. Blaming it on bad gas, I drained and filled tank a couple times, added Techron, etc. No change, eventually got worse. Finally found that the locking tab on coil wire at right side primary was not engaged.

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Appreciate the responses,

 

I did check all connections. Found some upper coils at bobs bmw online. PN. 12 13 7715853R. Has anyone tried these says its compatible. They are made by Beru.

 

Thanks

John

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Finally was able to get bike outside and do some troubleshooting...

 

Changed changed upper plugs no real change. Alternately disconnected primary coils stumble was even more evident.

 

Finally connected FPC bypass cable and problem is gone completely? Now question is which controller to get? 16 14 7720776 or 16 14 7720777. Not sure what's the difference?

 

Does anyone know besides price difference?

 

Thanks,

John

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You want the 16 14 7720776. Per RealOEM and the Max BMW fiche the more expensive 16 14 7720777 is intended for "official vehicles" (RT-P police version) with extra radio noise suppression.

 

I'm glad you were able to isolate the problem. I gather that while FPC failure takes many forms, it is not usually restricted to such a consistent RPM range.

 

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Afternoon John

 

You might (first) try going through your local BMW dealer as BMW NA was offering a good will warranty on the FPC's due to early design failures. Not sure if that is still in effect or not but worth a try anyhow (especially if you have the early SILVER low fin FPC)

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