My first 'Strand'... but at least it's not the drivetrain...

[smiller]

On the way home from work today, moderate rain falling, enjoying myself... when the engine stopped (R1100RT). No sputter, just an instant stop like I turned off the ignition with the key. Cranked easily but would not start.

 

I'll skip the part about standing in the open in the rain for an hour, but with the help of a friend got the bike home. I tried to start it again and it cranked for about 10 seconds then sputtered and started, and ran normally (which is of course the worst thing that could happen in terms of diagnosing the problem.) Luckily the engine died again after about 30 seconds of running... thought I was in trouble there for a while.

 

So... hall sensor..? Guess I need to dig up some links on testing them. Any other ideas?

[Rob L]

Yup! Hall sensor, check for spark. Mine died when I washed it (won't make that mistake again )

[beemerman2k]

Yup! Hall sensor, check for spark. Mine died when I washed it (won't make that mistake again )

 

For years I'd take my bike to the local car wash and use that high pressure hose on it that everyone says you shouldn't use. My bike never stalled ever. I rode through the California downpours last winter. Still, engine ran like a champ.

 

What's with the Hall Sensor? Can it be damaged or is it a matter of it either is a good part or a bad part? So far never an issue with me, but I have a hunch that in time...

[smiller]

but I have a hunch that in time...

 

With your recent luck, probably...

 

The hall sensors (and associated wiring) are subject to eventual aging and if they die... you stop. No way to really predict when or if you'll have a problem, but obviously the chances increase with mileage. I have read that they can be sensitive to moisture in their old age so I kind of suspect that here. I just found a trove of info on the net; looks pretty easy to test them. A new sensor plate assembly is near $250 list so... ouch. I might just order the sensors themselves from Newark Electronics (2 for $25) and do the repair myself. Newark ships same day so that may be the fastest way to go as well as the least expensive. If anyone has any experience with this please speak up...

[BABABeemer]

I wonder if as a preventive measure, you just spray a little WD-40 behind the lower pulley and extend the rear part of the front fender, this frequently-occuring problem could be eliminated?

Just a thought.

[smiller]

I wonder if as a preventive measure, you just spray a little WD-40 behind the lower pulley and extend the rear part of the front fender, this frequently-occurring problem could be eliminated?

Dunno. The bikes been ridden through heavy rain many a time with no problems. I kind of have a feeling that if the insulation material around the hall sensor coils is intact then no amount of water will bother it, and once that material breaks down over time then there's probably nothing you can do to keep moisture out. I don't think that there's really any kind of preventative maintenance one could do to prevent it.

 

It wasn't much fun tonight but no big deal... however it would be most unpleasant to have this occur during a long trip, and it's kind of an expensive part to have along as a spare. Just one of those cross your fingers things I guess.

[Kathy R]

What year do you have and how many miles? I just want to know what to add to my prayers at night. My 02 with 40k has had no issues, thus far.

[smiller]

'96 with 65k miles. I think you can probably wait a few years to add it to your prayers, but then again, never hurts. I didn't pray and look what happened...

[bmwmick]

that here. I just found a trove of info on the net; looks pretty easy to test them. A new sensor plate assembly is near $250 list so... ouch. I might just order the sensors themselves from Newark Electronics (2 for $25) and do the repair myself. Newark ships same day so that may be the fastest way to go as well as the least expensive. If anyone has any experience with this please speak up...

 

Seth,

I've rebuilt a couple of them. Go read this entire thread:

http://tinyurl.com/dnedt I even put a good source for high temp teflon insulated wire.

The insulation that BMW used is NOT up to the task. Once the insulation breaks down, add just a little moisture and you have a good conductor BETWEEN wires.

[Steve_Reinig]

I have a 96 RT with 126,000 miles, with no tell tale signs. May be proactive this winter and replace it.

[Jim VonBaden]

Remember this? My very similar problem!

 

Check your coil too! That's exactly what happened to me.

 

Jim

[smiller]

Jim - Thanks for the info. My problem/symptoms are virtually identical to yours and I am suspecting the hall sensors but now will pay close attention to the coil as well. Do you happen to remember how the bad coil tested in terms of resistance on the primary & secondary? I see you mention that in the thread but I'm not sure I understand what you were saying.

 

Mick - Thanks for the link to the wire vendor and I will be sure to inspect the wiring harness. When you rebuilt your sender did you fashion a mandrel for peening the rivets?

 

Anyone - Since it appears from reading these threads that bad input from the hall sensors will prevent both spark and fuel, could this fact be used to isolate the problem away from the coil? (since a coil problem would only affect spark but not fuel delivery.)

[smiller]

OK, definitely not the hall sensors because the fuel pump operates during cranking, and there is pulsed power at the injector connectors. From what I've read in the other threads this wouldn't be happening if there was no hall input since in that case both fuel and ignition would be dead, but I have only lost ignition.

 

Bigger clue, there is an intermittent (meaning just long enough to torture me) chattering sound which sounds like it is coming from the area under the battery, a little louder on the right side. I first thought the coil may be arcing but it doesn't sound like a crack, more like a thud like a relay chattering... but I don't know of any relays in this area. The sound is definitely not coming from the fuse/relay box, nor from the Motronic unit. When I hear the chattering sound the tach goes crazy and the fuel pump runs continuously (probably because the ignition circuit is being rapidly pulsed so the pump never times out as it usually does when you turn the key on.)

 

So, any ideas? Are there any electrical components in this area that could create this sound?

[leikam]

You mean aside from the fuel injectors?

[bmwmick]

Bigger clue, there is an intermittent (meaning just long enough to torture me) chattering sound which sounds like it is coming from the area under the battery, a little louder on the right side. I first thought the coil may be arcing but it doesn't sound like a crack, more like a thud like a relay chattering... but I don't know of any relays in this area. The sound is definitely not coming from the fuse/relay box, nor from the Motronic unit. When I hear the chattering sound the tach goes crazy and the fuel pump runs continuously (probably because the ignition circuit is being rapidly pulsed so the pump never times out as it usually does when you turn the key on.)

 

So, any ideas? Are there any electrical components in this area that could create this sound?

 

Seth,

This is EXACTLY the symptom of a failed HES wire harness.

Yes, I did make a peening tool out of a hardened bolt.

h

http://users.rcn.com/dehager/service/oilhead_hall_sensors.pdf

Mick

[smiller]

You mean aside from the fuel injectors?

 

Yes, it's definitely not coming from the fuel injectors.

 

This is EXACTLY the symptom of a failed HES wire harness.

 

Really. Hmmmm... think I'm gonna take your word on this one because it somehow seems likely even though it doesn't seem to explain why I'm seeing fuel or why the fuel pump operates after bumping the starter. But I'm fresh out of any other ideas so I'm headed under the front cover to check it out... BTW do you have any idea where the chattering sound is coming from?

 

FWIW it doesn't seem like it could be the coil... it shows no evidence of any problem and the primary measures 0.8 ohm and the secondary measures 8k ohms which is pretty close to measurements others have done on a new unit.

 

Back to the garage...

[bmwmick]

This is EXACTLY the symptom of a failed HES wire harness.

 

Really. Hmmmm... think I'm gonna take your word on this one because it somehow seems likely even though it doesn't seem to explain why I'm seeing fuel or why the fuel pump operates after bumping the starter. But I'm fresh out of any other ideas so I'm headed under the front cover to check it out... BTW do you have any idea where the chattering sound is coming from?

 

FWIW it doesn't seem like it could be the coil... it shows no evidence of any problem and the primary measures 0.8 ohm and the secondary measures 8k ohms which is pretty close to measurements others have done on a new unit.

 

If the coil measures good and passes the 'sniff' test, it's probably good. Specs are 0.5 Ohms on the primary and 7.5K Ohms on the secondary.

 

The upper Hall Effect device signals the Motronic to fire the coil, the lower one signals the Motronic to fire the injectors. When the wires short internally, the tach goes nuts and the coil and/or injectors fire randomly. (just ask Paul Glaves)

 

My money is on the harness being bad but I would replace both sensors while your at it. $12.31 each isn't bad from Newark In One.

 

Mick

 

Back to the garage...

[smiller]

The upper Hall Effect device signals the Motronic to fire the coil, the lower one signals the Motronic to fire the injectors. When the wires short internally, the tach goes nuts and the coil and/or injectors fire randomly. (just ask Paul Glaves)

 

So now I'm wondering if maybe it was the injectors I was hearing... perhaps if they were going off randomly and together the 'stereo' effect may have made it sound like the noise was coming from a point in between them.

 

My money is on the harness being bad but I would replace both sensors while your at it. $12.31 each isn't bad from Newark In One.

 

I'll have the sensor plate out in about an hour and will be checking it out. Replacement hall sensors are showing up from Newark Electronics tomorrow via FedEx but my challenge may be finding a local source for some high-temp capable wire.

 

Thanks again for your input.

 

To be continued...

[smiller]

Well, damn... can't find anything wrong with the hall sensor assembly no matter what I do. I've tested with an LED and they work... they work heated to way beyond the point you can touch them without getting burned (DAMHIK), they even work immersed in water. I can twist the harness any which way and tie it in knots while observing the operation of each sensor, no problem. I then checked between each lead with an ohmmeter to all the others while bending the harness all over the place and couldn't detect anything that even remotely looked like a short.

 

So... even with all that is it still possible something in the assembly is bad? I'm kind of loathe to tear into something that passes every test I can throw at it.

 

And if it's not the hall assembly and not the coil , and not a relay (I swapped all the identical black relays around), then what is left?

 

That's what I get for thinking this would be easy.

[bmwmick]

Seth,

Just rebuild it or swap it out with a known good one. I'm still convinced (with your symptoms) that the HES is toasted.

 

Mick

[smiller]

Just rebuild it or swap it out with a known good one. I'm still convinced (with your symptoms) that the HES is toasted.

Yeah, after thinking about it overnight that's about where I am with it. The symptoms just point too strongly to the HES to ignore (that, and I'm at a loss as to what else it could be.) Thanks again for all your input.

[Jim VonBaden]

Well, damn... can't find anything wrong with the hall sensor assembly no matter what I do. I've tested with an LED and they work... they work heated to way beyond the point you can touch them without getting burned (DAMHIK), they even work immersed in water. I can twist the harness any which way and tie it in knots while observing the operation of each sensor, no problem. I then checked between each lead with an ohmmeter to all the others while bending the harness all over the place and couldn't detect anything that even remotely looked like a short.

 

So... even with all that is it still possible something in the assembly is bad? I'm kind of loathe to tear into something that passes every test I can throw at it.

 

And if it's not the hall assembly and not the coil , and not a relay (I swapped all the identical black relays around), then what is left?

 

That's what I get for thinking this would be easy.

 

Sorry for the late reply.

 

My coil tested out perfectly normal, and the bike would run for a minute at best before it would die.

 

The coil has to heat up fron the internal short before it would go bad. It is very difficult to test. But a coil is pretty cheap, and it is definitely what fixed mine. I even used the old HES on another bike with no problems.

 

Jim

[smiller]

Thanks for your note Jim. Well, I sure hope it's not the coil because last evening I replaced the hall sensors. I decided that the symptom of the tach jumping around and what may have been the injectors chattering just pointed too strongly at the hall sensors to ignore the symptoms. It's raining today so I'll wait to road test until it's dry (not really looking to repeat my experience Wednesday night when the bike initially died), but all indications are that replacement of the hall sensors fixed the problem. I ran the bike for about half an hour and purposely got it rather hot as a test and no problems... before the replacement I couldn't get the bike to run for more than a few minutes. The sensor harness was in good shape so it appears that one of the hall sensors had gone flaky in way that was not possible to reproduce off of the bike. Lesson learned was that you apparently can't use the availability of fuel (or spark, if the other sensor fails) as any kind of diagnostic here since the results of an intermittent sensor can cause all sorts of havoc.

 

Thanks to all who offered comments and assistance, reading about everyone else's experiences was very helpful! Sometimes I think the BMW community may be one of the most compelling reasons to own a BMW motorcycle.

[bmwmick]

Seth,

I still think you should have rebuilt the entire harness. You now have NEW sensors with a deteriorating harness.

Did you make a mandrel? The first one I rebuilt, I didn't have a mandrel and the peening job was a little crude. I carry that one as a spare now.

 

Mick

[smiller]

Oh yeah, I know. I definitely would have rebuilt the entire harness if I had suitable wire but I had reasons that required me to get the bike running ASAP, and inspection of the harness didn't seem to reveal any significant deterioration (famous last words which I will remember as I kick myself if the bike stops the next time it rains.)

 

I did make a mandrel, wasn't very difficult. I happened to find a heavy nail that had a .195 diameter which seemed perfect, and the relatively soft metal made it easy to work with but was still tough enough to do the job. I think it only took me about a half hour to make, definitely worth the effort as you know. Mine is in my tool box, hope I don't need it again too soon. Grinding out the rivets was kind of a PITA, though.

 

Thanks again for the tips.

[No_Twilight]

Sorry to jump in here late but I've been offline. Your symptoms are very similar to my HES failure including refiring once. The failed HES will generally give enough signal to run the fuel pump so that isn't an indicator. I read that the early HES units manufactured by Bosch used the wrong wire so your insulation breaks down. On my 95 with 75K miles, I found the insulation very badly cracked INSIDE the heat shrink tubing that they use on the wires around the joints. I replaced the wire.

 

I made a mandrel on my lathe. If anyone else wants one let me know. On a lathe it is quick easy, and perfect. --Jerry

[smiller]

On my 95 with 75K miles, I found the insulation very badly cracked INSIDE the heat shrink tubing that they use on the wires around the joints.

 

OK, you guys are freaking me out here. I didn't inspect every inch of the harness and since it's pretty easy to pull the HES sensor unit I guess I'll go ahead and replace the wiring as well, regardless of its appearance, the next time I have the bike apart for some reason (which hopefully will not be this reason.)

[No_Twilight]

OK, you guys are freaking me out here. I didn't inspect every inch of the harness and since it's pretty easy to pull the HES sensor unit I guess I'll go ahead and replace the wiring as well, regardless of its appearance, the next time I have the bike apart for some reason (which hopefully will not be this reason.)

 

If you need some wire, let me know. I think I have some nice Belden left over. It has a very high temp rating. But if you rebuilt it and it fixed your problem, hopefully everything will be ok. --Jerry

[axabmw]

It's raining today so I'll wait to road test until it's dry (not really looking to repeat my experience Wednesday night when the bike initially died),

 

I had an old Honda CD250 that would misfire or cut out in the wet. It ran perfectly in the dry. It was the HT leads and coil shorting out!! A quick spray with WD40 always cured the problem for a mile or so.

By all means try it in the dry, but test in a good downpour before any long trips.

[smiller]

Well, had some time so I removed the HES sensor plate assembly to check all of the insulation. Sure enough, the portion under the clamp that holds the cable to the sensor plate had completely failed... all four conductors had cracks in the insulation, which just crumbled away under my touch. I still believe that one of my Hall sensors had failed but now I wonder if the failure was caused but a short (I would think that the sensors would be internally protected against this but maybe not.) I replaced the entire harness with high-temp rated wire (thanks for the help you-know-who-you-are) which should be a complete fix for the issue.

 

In any event this is definitely a 'time-bomb' problem for many oilhead owners, or perhaps all oilhead owners since even though several notes I've seen refer the the insulation problem as being with 'early bikes' I haven't seen any definition of what 'early' is, nor have I seen any report confirming that 'later' Bosch HES assemblies were in fact built with the proper wire. If not then I wouldn't even trust a new part, or at least not for more than 50k miles.

 

The fix is relatively easy but the issue is still pretty annoying since it is entirely predictable and preventable. My guess is that most HES failures are because of this problem but since most owners have this work done at a dealer (who replace the HES with an entirely new assembly and probably just toss the old part in the trash) that even the dealer may not be aware of the real cause of the failure. You might think that BMW would eventually catch on and inspect some of these, or maybe they have... since were dealing with BMW we will never know.

 

As a result of my experience I would strongly advise owners of high-mileage bikes (of any year) to check this out. If not, due to the nature of the problem the first time the HES fails it will very likely be in the rain, and if Murphy is at all around it will also be at the beginning of a long-anticipated trip. If not repaired proactively I cannot think of any reason why any 1100/1150 would not eventually see this failure occur.

[bmwmick]

Seth,

My guess is that your original sensors were just fine. When It began shorting between the wires, it confused the Motronic and it quit. Subsequent attempt netted you the random sparks and the tach wiggle. Sure signs of a failed harness.

I know they changed the HES part on the 1150 bikes but since I've never had one of those HES units in my hand, I don't know if they upped the rating of the wire insulation.

Someone here once suggested the junk insulation was a "safety issue" in that the engine would quit before it got too hot. I think that is totally false. The factory sourced the HES assembly from whoever would build it the cheapest and WE get to live with those decisions.

 

Mick

[smiller]

Some additional troubleshooting that I didn't post leads me to believe that a hall sensor may have failed, but given the condition of the harness I suppose it is quite possible that the harness was indeed the entire source of the problem. Will never know now but in any event the harness insulation problem is very real. It is also impossible to detect other than by tearing the harness apart... if you think that you can diagnose it any other way (as I erroneously did)... you can't. And when it fails you will have a completely dead bike by the side of the road in the rain. Believe me, if you have even the slightest doubt it is worth a few hours to check it all out.

 

The HES seems to be a standard Bosch part and my guess is that it was intended for use in automotive distributors and such where the insulation requirement isn't as critical. The part of the harness that was under the tank (which also sits in a pretty hot environment, similar to under-hood conditions in a car) was fine, but the part of the harness that is clamped down to the engine block in the oilheads receives a lot more heat and I don't think that Bosch had envisioned or designed for this. That would be BMW's job and it would appear that they failed pretty miserably. Perhaps they caught it and corrected the problem down the line (or maybe not!), but if so there should have been a warning issued because as it sits the harness will fail when the bike gets to some number of high miles (but only 65k in my case.)

[bluedawg]

Seth, my bike is a 2000. So far no problems with the HES or it's wiring.

Do you think it would be a good idea to open it up, unclamp the wires and coat them with a high temp silicon or something like it?

Mike

[smiller]

Seth, my bike is a 2000. So far no problems with the HES or it's wiring.

Do you think it would be a good idea to open it up, unclamp the wires and coat them with a high temp silicon or something like it?

That's a tough call. I would guess that a 2000 would not be considered an 'early' model, but as I said I've been unable to uncover any information as to when the HES harness problem was fixed, if it ever was, so if your bike has over 50k miles I would advise checking. In all cases I've heard of an HES harness failure gave no advance warning at all and stopped the bike dead on the road, and most of the initial failures seemed to be in the rain... a most unpleasant combination of circumstances.

 

If you want to check you need to pull the HES and cut open the heat-shrink tubing under the clamp on the sensor plate. If the insulation looks perfect then I guess you're OK, although at that point you may want to replace the wire in the harness since you've gone that far. As I said, I have no idea what you'll find on a 2000 model-year bike.

 

BTW for fun I took a small sections of Teflon-insulated and standard wire and heated them with a heat gun. The standard insulation started to burn away within about 10 seconds. I went about a full minute with the Teflon insulation, at which point it was glowing red and the color of the orange wire had turned brown (I never could get it to actually burn.) I thought that I had succeeded in at least damaging it but when it cooled the insulation turned back to orange and it was impossible to tell by looking at it that it had ever been heated at all! That stuff is tough... I think it will last...