Electromagnetic Interference

[twistyguy]

Hey Guys.

 

I'm new to the forum--it seems like you are a bunch of well informed motorcyclists. So I'm asking for your help on a problem that has confounded BMW dealers I've worked with.

I live in the Washongton, DC area. I ride a 2011 R1200R. Whenever I ride over two particular over passes--the first traveling north from I-95 onto I-495 West toward Tysons, the second traveling North on I-270 just before exit 15, my bike stutters, backfires, and then the check engine and ABS light go on. This happens 100% of the time when I cross over these overpasses. The bike rides okay after the incident, but probably without the ABS. When I turn off the bike and restart it, the check engine and ABS lights are off and the bike is back to normal. There must be some sort of surveillance equipment that sends out a powerful electromagnetic field that must interfere with the bike's electronics. I've taken off most of the electronic farcles (eg--MottoBozzo fog lights, booster plug) and it made no difference. When I've enquired with about the problem with my local BMW dealer and a good independent BMW service guy, they are less than enthusiastic in figuring out what is wrong and throw up their hands and chalk it up to electrical gremlins. I contacted BMW North America who suggests I work with the dealer who is useless.

 

So my question is can any of you recommend a way to electrically shield the ecu or any other possible solutions?

 

Thanks.

 

Peter

[dirtrider]

Afternoon Peter

 

I haven't done much work with the newer 1200R bikes so I'm not that up to speed on the main wire harness & sub harnesses of the ® bike.

 

If an 1200RT then my first suggestion would be to verify that ALL the CAN (CanBus) terminator resistors are in place on any missing CAN accessing accessories (like tire pressure controller or possibly anti-theft alarm controller. Being an ® bike I'm not sure of how many open CAN terminals are even on the bike. Basically look for any open connectors that have CAN (controller Area Network) access.

 

If you have access to a GS-911 then maybe do a quick failure code read right after the shut down (might point to what part of the system is being effected by the RFI interference)

 

Also make sure that the BMS-K (fueling computer) case ground is working correctly.

 

Otherwise it is probably going to be hit & miss on finding your problem as it might not even be RFI related.

 

If it really is RFI related then the logical approach would be to find another rider with a very similar motorcycle then ride them side by side across the very same interference area.

 

The problem is: if it is RFI related then the RFI might be directly entering the fueling computer or CAN system. Or it might be migrating in through an attached wire harness that acts as an antenna.

 

If you have ANYTHING from GPS, to add-on lights to ?? then try completely disconnecting those accessories including any wires that tie into the bike's electrical system.

 

I have chased very similar RFI interference on automobile systems & it isn't an easy task to track down without a lot of support instrumentation & the help of a good savvy electronics group.

 

Make DARN SURE that you don't have a side stand switch problem or your foot is not hitting the side stand as you cross those problem areas.

 

 

Added: I'm not near my service bulletins at the moment but if I recall there was a bulletin on the R1200R bikes (as well as other BMW models) that covered engine cut-out due to water getting into the side stand switch. I believe the bulletin covered BMW 1200 bikes bought between January 1, 2011 and September 20, 2013.

 

Next time that you are at your dealer have them put your VIN into their computer & check for side stand switch recall or bulletin (or just call the dealer).

 

 

 

 

Edited February 25, 2017 by dirtrider

[w2ge]

As always, dirt rider is the man and his ideas are probably the best to follow. But, you asked a question how to electrically shield your ecu. That is done by just making an intact metal cage around the whole Ecu and that it is grounded.

 

It doesn't have to be solid metal it can be like a screen...

 

Google 'faraday cage'...

[twistyguy]

Thanks D.R. and Phil. Excellent advice--much appreciated. As the problem never occurs except over those overpasses, I believe it must be an electromagnetic interference problem. The simplest solution (to my simple mind) would be to shield the electronics instead of trying to track down every circuit. I've removed the most likely accessories that would have caused the problem. I've never heard of anyone else with this problem on the R1200R forum. But they didn't seem too interested to contribute when I asked them. I'll try to rig up some sort of electrical shield cage (if I can figure out where the ECU and Can Bus is!) I'm not totally mechanically challenged, but not all that experienced either. Thanks advice for the advice.

[dirtrider]

Thanks D.R. and Phil. Excellent advice--much appreciated. As the problem never occurs except over those overpasses, I believe it must be an electromagnetic interference problem. The simplest solution (to my simple mind) would be to shield the electronics instead of trying to track down every circuit. I've removed the most likely accessories that would have caused the problem. I've never heard of anyone else with this problem on the R1200R forum. But they didn't seem too interested to contribute when I asked them. I'll try to rig up some sort of electrical shield cage (if I can figure out where the ECU and Can Bus is!) I'm not totally mechanically challenged, but not all that experienced either. Thanks advice for the advice.

 

Morning twistyguy

 

The ECU is already shielded as it has a fairly heavy alloy case around it that s-h-o-u-l-d be grounded to the bike's chassis (make sure that ground is intact)

 

Don't discount the possibility of the RFI entering through CAN (CanBus) wiring or even the main harness. The CAN wiring is supposedly RFI shielded but any open connectors with CAN wiring access needs to have a termination resistor across the exposed terminals.

 

Also don't completely rule out mechanicals as the problem, some riders change their riding position as they cross certain road changes, even an altitude change can effect foil switch contacts, or effect moisture pressure in switch's.

 

You might try pulling the clutch lever in just before the usual stalling point then coasting through the bad area to see if that effects the engine stalling (if it does then look into side stand switch).

 

I have seen RFI or EMF effect engine runability & skew fueling control but haven't ever seen it completely shut an engine off when riding at speed locked in higher gears.

 

 

[Don_Eilenberger]

Don't discount the possibility of the RFI entering through CAN (CanBus) wiring or even the main harness. The CAN wiring is supposedly RFI shielded but any open connectors with CAN wiring access needs to have a termination resistor across the exposed terminals.

DR,

 

FWIW: The only shielded wiring I've seen on the R1200R are the various sensor wires - the ABS sensors, the cam sensors, temp sensors, etc.

 

CAN_bus wiring - at least on my Porsche and as far as I can tell the R1200R is a simple twisted wire pair. The twisted pair is done to cancel EMI - just like CAT wiring for Ethernet.

 

Have you seen different?

[TestPilot]

Peter,

 

You might check with the local highway department or the state Department of Transportation and see if they have any monitoring equipment installed on those overpasses. They may have remote sensors to monitor traffic or loads on the structure and radio back their readings.