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Thread: Hall Effects Sensor Failure

  1. #1
    Join Date
    May 2007
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    elkmont
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    Exclamation Hall Effects Sensor Failure

    Most of us have heard stories of being left along side of the road when our BMW just stopped running without any prior indication of problems. Most shade tree BMW mechanics will immediately tell you there has been a Hall Sensor failure. In fact this may be true or it may not be true. I will relate three experiences I have had with sudden engine stoppage without prior notice.

    First what is the Haul Effects Sensor? In simple terms, on the oil heads (the only ones I know about) there are two Haul effects sensors mounded on a steel place the fits on the front of the oilhead engine behind the drive pulley for the alternator. These sensors sense Top Dead Center (TDC) and 180 degrees on the crankshaft. On sensing these positions a signal is sent via wiring to the Motronic unit which in turn tells the coils to fire the appropriate spark plug and to squirt an appropriate amount of fuel through the fuel injectors. Of course the Motronic unit is monitoring a whole bunch of other crap such as battery voltage, oxygen sensor, etc.

    1. Two years ago, Angie's R850R decided it would not crank after stopping for fuel. I had to haul the bike home from Moulton. Every thing pointed to a Haul Sensor failure. I decided to repair the old Haul Sensor by replacing the sensor on the plate (actually a friend did it for me.) After doing this the bike ran fine for approx. 2000 miles then it suddenly quit again. This sudden engine stoppage continued for about 3 months and cost us our bike trip to Alaska. The problem was literally driving me nuts and everyone kept telling me to change the Haul sensor. The problem was that it would run fine on some occasions and just decide to go dead whereever it seemed most inconvenient like Phenix City. I finally discovered she had a couple of grounding problems. The bike had lost its ground from the fuel sensing unit and I replaced this at a cost of $250+ then the problem occurred again. I finally noticed a short in the wire from the tachometer where the wire crossed a frame member. Repaired that and have had no prolbem in last two years. This bike had about 45K miles on it at the time.

    2. Last year after swimming my R1100GS during a Waterloo run, the bike just shutdown about a 1/4 mile from the swim site. Had to haul the bike home. All indications were Haul Sensor failure, but first I wanted to inspect all the wiring for shorts since the bike has had a long history of wiring problems. Not finding any wiring problems, I ordered a Haul Sensor at about $250. When I removed the old Haul sensor, I noticed all of the lead wires from the two sensor to the pigtail that connects to the Motronic unit were brittle, cracked, and in a generally poor condition. I have attached photos of these wires (R1100GS-1&2). After the replacing the Haul sensor the bike cranked fine. This bike had about 92000 miles at the time of failure.

    3. Sunday on the way home from the Chicken Rally, Paul Thorne's R1100R suddenly stopped running after he had just ridden through a rain shower. Terry Ware stopped to check on Paul and diagnosted the problem as probable Haul Sensor failure. Terry called me and asked if I could possibly help Paul since he did not have room in his trailer to carry Paul's bike. I told Terry, I thought I had an old Haul sensor and that I might get Paul back on the road. Short story - after hauling Paul's bike to my house, I could not find a Haul Sensor other than the old one I removed from my R1100GS and I knew the wiring on it was crap. Paul and Gail left the bike with me and I removed the Haul Sensor. The wiring on it may have been worse than the wiring on my R1100GS sensor. (See attached photos R1100R -1,2&3) I asked my friend, Mike Weyler, to come over Monday and see if we could replace the wiring on Paul's Haul Sensor. In fact we did and after reinstalling the Haul Sensor, the bike cranked fine and ran fine on a short 15 mile trek. Today I replaced the wiring on my old 1100GS sensor so I will have a spare next time. Paul's bike had approx. 96,000 miles at the time of failure.



    What have I learned from this? Rarely is it that the actual Haul Effects Sensors fail but rather is a failure of the wiring which is attached to the front of the engine and absorbs all the heat over all the miles. Both of the R1100's had approximately the same mileage and the wires on both sensing units were in a similar poor state. If I owned a R1100 or R850 with over 75,000 miles I would immediately replace the Haul Sensor as a preventive measure. It doesn't take long in a hotel and with a recovery charge to pay for the $250 Haul sensor and labor if you have to have someone else replace it for you.

    I don't have any experience on R1150 Haul sensors except that I know the part number is different from a R1100 Haul sensor. I do know I have 130,000+ miles on my R1150GS with no problems to date with the Haul Sensor, but I am seriously considering changing the unit out before a trip out west this fall. Then I can carry the old one with me along with all the other just-in-case parts I carry.

    Why did I take the time to write all this crap up? Just to warn you that an ounce or $250 worth of prevention may save you a pound of problems down the road and ruin a good trip. Just envision the Haul Sensor dying on your high mileage bike late on Sat afternoon and ain't no dealer gonna to be open until Tues morning and then they have to order the part (cuz there ain't three dealers in the US that carry this part in stock.) If you are lucky and you didn't deal with Bogarts your part may arrive by Friday and the dealer may grant you special favor and install it so you can be back on the road on Sat. That's recovery fee, one week in the hotel plus meals that you didn't budget for.

    http://picasaweb.google.com/duboisga...JePkoOa0pWZSw#


    Outlaw's tech talk for May.
    Attached Images Attached Images
    Last edited by dixieoutlaw; 05-26-2009 at 11:18 AM.
    Charm and Mr. Congeniality

  2. #2
    Join Date
    Oct 2007
    Location
    Huntsville
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    Default

    Gary,

    We were talking about this problem at the rally on Sat. Its ironic this problem popped up. Thanks for the photos. How long does it take to get the sensor off and are any special tools required? I think I will pull mine out and rewire it at a minimum seeing that my R1100GS has 82k on it. Maybe I will do it this weekend. I think I want to get it done prior to the Cruso meeting.
    Erik Bahl
    Huntsville

    "Those are some fine P-nuts"

    2004 R1150R
    1929 R63 OHV - 2014 Cannonball Run Entry #63

    www.cannonbahl.com

  3. #3
    Join Date
    Apr 2007
    Location
    Birmingham, Alabama
    Posts
    1,492

    Thumbs up

    Thanks for the well written article Gary.

    The last time I was at Rick Jones', he showed me a new replacement unit for Hall sensors that he is developing. I don't remember all the details, but he thinks very highly of the unit and said it is less expensive than the OEM. If Rick thinks highly of something, you can take it to the bank that it is a superior product. I think you will find that the Hall units are now much more expensive than $250.00.
    Bob Steber
    1976 R90s Odalisque
    1995 R100GSPDC Long Tall Sallie
    2007 K1200LT Traveler

  4. #4
    Join Date
    May 2007
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    elkmont
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    Default

    Erik,
    I apologize. I took about 30 minutes earlier today to detail the procedure you need to go through to rewire the haul sensor. I just now realize that for some reason it didnot post. I will try to rewrite later tonight.

    Gary
    Charm and Mr. Congeniality

  5. #5
    Join Date
    Oct 2007
    Location
    Huntsville
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    Default

    Does anyone have any old R1100 hall sensors that were left over after a replacement laying around? I would like to get my hands on a couple.
    Erik Bahl
    Huntsville

    "Those are some fine P-nuts"

    2004 R1150R
    1929 R63 OHV - 2014 Cannonball Run Entry #63

    www.cannonbahl.com

  6. #6
    Join Date
    May 2007
    Location
    elkmont
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    506

    Thumbs up Haul Sensor wiring repair instructions

    Erik,
    I will try to recall my words of wisdom that seemed to have died in the Web graveyard.
    No special tools required to remove the Haul Sensor. I set the engine to TDC and then use a long allen wrench as a locking pin. Iím sure you know the locking pin goes in the hole above the starter and slots into a hole in the flywheel. Then I remove the plastic front cover from the engine (you may have to remove the bottom bolt from the shock to get the cover off.) I loosen the alternator and let it slide down. On the GS I think I remember there is an oil by-pass line which has to be removed before you can remove the alternator belt (donít lose the little O-ring or crush washer.) The R1100R did not have this oil by-pass line.
    Use a 16MM socket to remove the bolt from the crankshaft pulley, and remove the pulley. Behind the pulley is a slotted timing wheel (not sure the proper name for this), but pay particular attention to the spur on the backside of this. The spur goes into the slot on the front of the crankshaft. The only thing that holds this wheel to the crankshaft pulley is friction and it is easy to get these misaligned when reinstalling and get the bolt in place (ask how I know.)
    Slide the fuel tank back where you can gain access to the connection between the wiring harness from the Haul Sensor and the wiring harness from the Motronic unit Ė this connection is inside the upside down clear plastic boot. It is a real PIA to separate the connector Ė suggest one or two long screw drivers to pry apart the hooks on the edges of the connector and maybe some nimble fingers. Now cut the quick ties and then hold up on the alternator and snake the connector under it.
    NOTE: Before removing the Haul Sensor plate, make several witness marks so you can realign the plate when you reinstall. I use a sharpie and outline the corners of the plate and if reinstalling the same sensor I make a couple of more witness marks from the plate to the engine. You should be able to put it back in place and not have to time the engine by doing the witness marks. Iíve had good luck with this method on removing and installing three Haul Sensors so far.
    Remove the three socket head screws from the plate and remove the Haul sensor. Now is a good time to inspect the inch or so of wires that lead from the connector to the enclosed sleeve. You should have 6 positions in the connector with the first position empty. The second is a yellow wire, then a red wire, then a brown wire then a black wire and last a clear wire. The clear wire does not attach to the Haul Sensors but is naked inside the bundle and is surrounded by a shielding foil. Note the wires coming from the haul sensors do not have the same color coding.
    There is a ďDĒ shaped grommet that I sliced on the flat side to remove Ė when I reinstalled this I used a dab of superglue to put it back together but not gluing it to the wire bundle.
    Now slice open the wiring bundle all the way down to where the connections are made from the Haul sensors (it doesnít seem as if the insulation from the sensors to this connection is as prone to cracking as the wires from the connector.) Try to separate the connector by pushing in the tab on the edge and prying open the sides ( used crooked needle nose pliers to do this.) Once I had the connector separated I was able to pull and pry the pins from the connector. I did this one at a time and separated the small crimp on the connector and cut the old wire as close to the connector as possible. I then put a new piece of wire which I had skinned back about 3/16 into crimp and squeezed the crimp over the insulation on the new wire and then soldered the wire to the connector. I then cut the wire to length and threaded through the portion of the connector which I had removed. Then in turn I did each of the other wires except the clear wire which I left intact. I used some really good wire with Teflon insulation that was left over from the Apollo program and sold at Govít auction.
    If you donít want to separate the connectors and crimping, I donít see why one could cut the wires about a ľ past the connector, remove all insulation, solder the new wire, then slide a small piece of heat- shrink all the way down to the pin and shrink it in place.
    Once I had all four new wires soldered, I slid a piece of heat-shrink over all five wires and leaving out the foil shielding. Donít heat this just yet.
    Now cut each of the old wires in turn about ľ inch from where they connect to the sensors, then slide a piece of small heat shrink up the new wire you are working with and stick it under the larger piece of heat shrink ( I used an alligator clip to hold all of this heat-shrink away from the heat that will be generated by the solder gun. Skin the insulation from both the old and new wire and solder them side-by-side keeping your joint small (no twisting of the wires.) Once the soldering is done then slide your small piece of heat-shrink down over the join and the connection if possible. Then do each of the remaining wires the same way. Once you finish all four wires, slide the larger piece of heat-shrink down over the smaller pieces you just joined, and shrink into place. Now screw the hold downs back in place and reassemble the end connector if you separated it.
    Reinstall all in reverse order using the witness marks and get the timing wheel and crank pulley in proper order. Tighten the crank pulley bolt to 37 ft. lbs. And then remove the locking pin.
    Install the alternator belt, tighten the alternator, reinstall the by-pass line, front cover and shock bolt.
    The bike should start.
    If you remove the Haul sensor and bring it over to my house I will help you do the wiring, most any night is okay, this Sat is bad but Sunday afternoon is okay.
    If you mess all this up, I have a spare repaired Haul sensor I will let you have until we can find another one to experiment with.
    Sorry about being so wordy, but en with that Iím afraid I might have left out a step or two. Any questions give me a call.
    Outlaw
    Charm and Mr. Congeniality

  7. #7
    Join Date
    Oct 2007
    Location
    Huntsville
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    Default

    Gary,

    Great job with the writeup. You have saved me a couple of potential headaches. I think I can handle the soldering and rewiring (lots of experience there). I decided to try to get another hall sensor and rebuild it prior to pulling mine out. So I am scouring for a used one right now.
    Erik Bahl
    Huntsville

    "Those are some fine P-nuts"

    2004 R1150R
    1929 R63 OHV - 2014 Cannonball Run Entry #63

    www.cannonbahl.com

  8. #8
    Join Date
    May 2007
    Location
    elkmont
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    Default

    To everyone, I guess this should have been under the GS and oilhead section of the forum. My bad. Maybe the moderator change move it to where it belongs.
    Gary
    Charm and Mr. Congeniality

  9. #9

    Default Hall Effect Sensor aka Crank Position Sensor

    Excellent job Gary. I can add two instances of Hall Sensor failure to your list, Terry, a traveler from Toronto on an R1100GS with lots of kilometers on it, and Martin Benson's R1100RT with about 95K on it. All of the sensor failures I have seen are the result of the wiring pigtail failing, except one where the Schmitt Trigger in the sensor itself failed. There is one place in the greater Birmingham area that stocks this sensor but I'm having trouble remembering the the name of the place. I think it is in Pelham. It is a Bosch part and sells for abut $225.

    The K75, K100, and K1100 as well as the R1150 series bikes also have Hall Sensors but I have not seen the failures on these bikes as I have with the R1100 & R850,s.

    If rewiring the Hall Sensor I would recommend the use of silicone insulated wire because it will withstand the heat much better. The heat seems to cause the insulation to get brittle.

    Ride on!! Hall Sensors be danged.
    T. Ware
    T. Ware

  10. #10
    Join Date
    Oct 2009
    Location
    Herts UK
    Posts
    10

    Default Hall sensor

    Dont know if this will heip you but MOTORWORKS sell them for £150.00, It's a UK company but might ship to US.

    John.

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