Left along the road--help please

[dwf]

I have a problem that has left me along the road twice on my '96RS (53K miles). Both times I have had to have it towed to the dealer with no defininitive answer as to what is causing the problem. I had ridden the bike probably 10K miles since the first occurence and the advent of this most recent occurence. I just finished a 6500 mile trip with no problem (until this most recent incident)

Here are the symptoms:

1. I left the house on Saturday a couple of weeks ago and rode about 80 miles to breakfast-- while returning home the bike died.

2. When I attempted to restart the bike it would crank and catch but shook violently.

3. The bike would then die again.

4. When I would try to start it, it would back fire and black smoke came out of the exhaust.

5. I could hear what sounded like relays cutting in and out.

6. Without trying to start it but with the switch on --the tachometer would swing wildly back and forth.

7. The bike finally started and I rode toward home --after approximately 60 miles the bike died again and the symptoms repeated. Except this time the bike would not start and I had it hauled to the dealer.

8. The only thing unique leading up to this situation is that I washed the bike the day before (I can't remember if I had washed it prior to the first incident of this occurring). But it seems as if water was in a connection it would have evaporated on the 80 mile ride to breakfast (or not started at home).

I have since gotten the bike back from the dealer and solution was the same as the first time this problem occured: the dealer unplugged all of the connections then re-plugged them. I rode yesterday and it runs perfectly. Obviously this does not do much for my confidence in the bike and I'm concerned about being left stranded again.

Has anyone experienced a similar problem? Any help would be appreciated.

[BillE]

Definitely sounds like a intermittent Hall sensor (ignition trigger). There has been a lot of discussion about this topic on the old site as well as this new one. Do a search and I sure you will come up with more than enough info to solve your problem.

[JimVonBaden]

Definitely sounds like a intermittent Hall sensor (ignition trigger). There has been a lot of discussion about this topic on the old site as well as this new one. Do a search and I sure you will come up with more than enough info to solve your problem.
I concur!

Jim:cool:

[Rando]

Along with the Hall sensor, how long since you have replaced your spark plug wires. Mine did something similar (especially after washing it) and replacing the wires was the cause. Rando.

[dwf]

Thanks guys for the input. I have searched the archives and the problem does sound a lot like the hall sensor. Though, one of the extensive threads turned out to be the coil as the problem.

If it is the sensor why do you believe the dealer unplugging and then
re-plugging the connections would "fix" the problem?

After washing the bike why could I ride 50-60 miles before it acts up?

Also, is it likely I could go 10K+ miles with no problem and then it act up if it is the sensor?

Obviously, I'm trying to be certain before spending $300 on a new sensor. This thing is driving me crazy in that I think it OK them bam here we go again after 10K.

Someone had mention a test of weting down the bike and then heating up the sensor with a hairdryer to get it to fail what do you think?

Thanks again for all of the help.

[AntonL]

If it is the sensor why do you believe the dealer unplugging and then re-plugging the connections would "fix" the problem?

In this case it is almost CERTAINLY the HES. This is exactly what mine did; when the engine conked out I would jiggle the wire to the HES and it would work again, for a little while. Dana Hager cut one apart and found that the fault was not in the sensor element itself but rather in the insulation of the individual wires leading to them. So by jostling the wire you are probably separating the ones that are shorting, but they will short again.

[JimVonBaden]

Thanks guys for the input. I have searched the archives and the problem does sound a lot like the hall sensor. Though, one of the extensive threads turned out to be the coil as the problem.
...

Someone had mention a test of weting down the bike and then heating up the sensor with a hairdryer to get it to fail what do you think?

Thanks again for all of the help.
I have an extra used sensor that I took off my bike that I would be willing to let you use for testing. Throw it on, drive it around for a while and if it is the problem, buy a new one. If you like just send me your address at JimVonBaden@comcast<remove this>.com

Or check the BMWST.com board, or Mike F on this board for a used one. He has a lot of used parts.

Jim:cool:

[dwf]

Jim,

Thank you for your generous offer to let me borrow your used sensor. With the intermittent nature of this problem (I did ride it for 10K between incidents) how will I be able to check it with your used one to be sure this is the problem. Since you sent me the message I went outside and hosed the front of the engine down and let it run until it warmed to five bars-----still runs fine! However, when it quit this last time after washing it I rode it 50-60 miles before it acted up. Now I am even more paranoid to ride it after hosing it down. What do you think. Thank you.

Wayne

[brakesqueal]

DWF, go to this link for repair to your existing hall sensor:

http://www.ebbo.org/2av54.php

[JimVonBaden]

I think Anton hit it when he said it was damage to the wires.

The best way to confirm or discredit this is to pull the front cover and the tank, both fairly easy, and pull the front lower alternator pully to access the HES. Very carefully check the wires all the way to the plug. If they are good, check the plug itself. It is not too uncommon for corrosion to build up on the plug contacts and cause a randomly intermittant problem.

Other than that, if you bike always restarts, I wouldn't let it stop you from enjoying your bike.

BTW there is a guy (Beemrmann69 or something like that) on the www.bmwst.com (http://www.bmwst.com) forum that rebuilds them and sells them at about half price.

Jim:cool:

[dwf]

The best way to confirm or discredit this is to pull the front cover and the tank, both fairly easy, and pull the front lower alternator pully to access the HES. Very carefully check the wires all the way to the plug. If they are good, check the plug itself. It is not too uncommon for corrosion to build up on the plug contacts and cause a randomly intermittant problem.

Other than that, if you bike always restarts, I wouldn't let it stop you from enjoying your bike.

BTW there is a guy (Beemrmann69 or something like that) on the www.bmwst.com (http://www.bmwst.com) forum that rebuilds them and sells them at about half price.


Jim, I pulled the tank yesterday and checked the plug and applied dielectric grease. After reading all of the history from the archives I am at least 80% convinced it is the Hall--though the coils stick in my mind (but I don't think that's it). What with the speedometer acting so eratic --it and other sympthoms point to the sensor. When I turn the switch on (not started) the spedo will bounce around wildly. When the engine tries to start it shakes violently like it is out of time---the engine loads up and belches black smoke--again sounds like the complaints other have had when they determined it was the sensor. As is most electrical problem it is indeed maddening. I don't relish the idea of spending $300 and the sensor turning out not to be the problem but I am at the point where I think I going to try it. I can't think of anything else that would cause the same sympthoms. Thanks for the tip on the rebuild.

Jim:cool:[/QUOTE]