Help please...HES questions.

[VinnyR11]

My bike has exhibited the exact same problems that others have diagnosed as HES. I've just read all the posts I can find on Hall Effect Sensor issues, and still have a couple of questions.

 

Bike was running as new. Raining fairly hard, but not a downpour. After a while (30 minutes), with absolutely no warning, the bike shut down. It may "run" for a little while (~10 seconds) before complete shut down, but it's more like a bump start running with no spark.. backfires, bucking, etc.

 

Pull off. Bike won't start. Cranks, but no start. The dash is lit, headlight fine, and it's cranking, so it doesn't sound like starter switch or side stand, although I did check them later and they are fine. Wait about 5-10 minutes, bike starts. Runs less great, bucks quite a bit every now and then. Then 25 miles later, same exact deal. Rinse and repeat one more time, until I got home. It was raining that day, so I thought it may be a wiring issue, but after reading posts here it sounds like what others with HES problems have written.

 

My local shop checked wiring head to toe, new dielectric grease where needed, checked HES which looked good "on the bench", but he said, as others confirmed, that it could still be bad. He said it might be something else and was reticent to put a new HES due to cost without knowing that's the problem. He was hoping due to the rain, that the wiring connections may have been the problem.

 

Bike ran great for 1 day, then the same exact thing happened yesterday in the dry.

 

Questions:

 

1) It sounds to me like the HES. I know very little about bike repair, so I don't usually listen to myself. Does that sound like the right road? Bike is a '96 R11RT with ~50K. It appears these things fail with some regularity (or at least the harness fails). I'm thinking of having them put in a new HES in any case.

 

2) People have posted that their tach went crazy during HES failure. I don't remember this at all. Would the tach always go nuts if the HES is bad, or can it read normally and still have a bad HES?

 

3) I don't remember whether or not the fuel pump came on when I tried to restart. I was so pis$ed that I just jabbed the key and tried to get it started. I'm thinking that the pump was running, because I'm almost certain that I would have noticed the quiet when turning the key. Yes, I learned my lesson, and will pay much closer attention next time.

 

Would you replace the HES? The $300 hurts but is not a deal breaker, so somewhat ignore the costs. Getting the bike back on the road is the #1 priority.

[OoPEZoO]

With 50k miles on a '96......I think its good preventitive maintenance regardless. If its not HES today, it will be one of these days. Especially if you ride in the rain from time to time. You are talking about 13 year old wiring that isn't designed to survive in the application it was put into. REALLY POOR design by BMW in my opinion. Mine crapped out at about 75k miles while I was on a roadtrip. I replaced it with a brand new one and have since put another 35k miles on it. I rebuilt my original with new high quality wiring and plan to replace my current HES next time I replace my alternator belt. Its not a fun replacement thing to do while on the road.

 

If you want to make sure.....next time it does it, just pull a spark plug wire and check for spark. A no spark condition would be a tell tale sign of a flaky HES

[smiller]

It sure sounds like the HES, and as Keith noted it's not a waste of money to replace the HES proactively on a high-miles 1100 (although $300 is a lot of money for the few feet of wire that's at the root of the problem 99% of the time.) A jumping tach needle is a common symptom but it is not always present.

 

As far as being a design failure, I can kind of see how it would slip through. The HES is a Bosch OEM part, and while it was designed for underhood temperatures it's likely the original designers did not envision the wiring harness being be clamped directly to the block. Perhaps some engineer at BMW should have have caught this but... that's how things go sometimes. The real mystery is why this glitch doesn't seem to occur on the 1150... either someone at BMW or Bosch eventually recognized the problem and changed the wiring harness spec, or no one did and the 1150 fleet just doesn't have enough miles on it yet to reveal the problem (the oldest 1150 is still seven years newer than the oldest 1100.) Time will tell.

 

 

[philbytx]

Certainly sounds like your HES if FUBAR'd....I just went through all that on a VERY low mileage (10k) 2000 R1100R and replaced the HES. Oh! And my old HES bench tested just fine!

 

A new HES is $209 and it is NOT that difficult of a job to R&R one, if you are handy with a wrench. You just need to be careful and precise!

 

If you haven't done so already, replace your Alternator belt while you are in there.

 

 

[T__]

Vinny, as others have suggested very possibly the HES.. Maybe worth a check to see if the fuel tank has vacuum in it after the stall. If you get whoosh when opening the fuel cap or it opens with difficulty maybe a problem with the fuel tank venting..

 

A plugged vent or problems in the evap system can cause the tank to go to negative pressure (vacuum).. That can keep the fuel from pumping out correctly.. Kind of a long shot as the fuel pump has a pretty decent pressure output but worth a look at anyhow..

 

 

Twisty

 

[eddd]

I replaced the wiring before I had a problem. It is a relatively easy job. Here is a link.

 

Way cheaper than $300.00

[VinnyR11]

Vinny, as others have suggested very possibly the HES.. Maybe worth a check to see if the fuel tank has vacuum in it after the stall. If you get whoosh when opening the fuel cap or it opens with difficulty maybe a problem with the fuel tank venting..

 

A plugged vent or problems in the evap system can cause the tank to go to negative pressure (vacuum).. That can keep the fuel from pumping out correctly.. Kind of a long shot as the fuel pump has a pretty decent pressure output but worth a look at anyhow..

 

 

Twisty

 

Thanks. Did check the fuel cap and it opened normally. Did not appear to have any pressure difference.

[VinnyR11]

Thanks all for the inputs. You guys are great.

 

To be safe, I'm having the HES replaced tomorrow. I'll update after about a week of riding.

 

Thanks again!

 

[outpost22]

Your failure sounds exactly like what mine did (mileage, year, and symptoms), except it wasn't raining when mine went kaput.

 

The repair is actually quite simple to do, and BMWMick used to sell rebuilt HES' here on the forum. If you can change an alternator belt, you can probably do the HES too. I would do the belt at the same time BTW since it has to come off anyway. I also cut my alternator cover in 1/2 horizontally, so changing the belt next time is really simple without having to remove the "shark fins".

[MrHondamatic]

So what I am picking up from all this is, it isn't necessarily the HES, as much as it is the wiring degrading. Is that correct?

[eddd]

So what I am picking up from all this is, it isn't necessarily the HES, as much as it is the wiring degrading. Is that correct?

 

Yes.

[smiller]

So what I am picking up from all this is, it isn't necessarily the HES, as much as it is the wiring degrading. Is that correct?

Double yes. Failures of the pickups themselves are uncommon, the problem is almost always related to failure of a few inches of insulation where the HES harness is clamped to the HES plate. Replacing the stock wiring harness with some wire with high temperature (Teflon, etc.) insulation is a permanent fix. Even better than a new HES actually because we still don't know for sure whether the insulation was ever upgraded on the OEM part.

 

 

[SKYGZR]

Nope..these things can be bad right out of the box. Read the thread "Perplexed."

[VinnyR11]

I replaced the wiring before I had a problem. It is a relatively easy job. Here is a link.

 

Way cheaper than $300.00

 

Thanks a lot for the tip and link. I'm sill going to go for the new sensor just for an extra level of peace of mind.

[MrHondamatic]

Since mine is obviously still working, I'll check out the wiring first chance I get. It's easy enough to replace a few feet of wire in the garage, as compared to out on the road.

[philbytx]

With all the HES issues posted recently, including my own. If the HES powered wire shorted to one of the HES Signal wires, would it not, in this particular instance, harm the sensor?

 

Just a thought....as wiring DOES test out ok but we have seen, what appears to be, the occasional HES wiring/sensor issues.

 

[OoPEZoO]

no....calling it a "sensor" makes it sound more sophisticated than it actually is. In common man speak it is literaly a few magnets with wires attached to them. There is a square/rectangle cutout on the crankshaft pully that causes an electrical pulse everytime the cuttout passes one of the magnets. That tells the Motronic unit when to fire the spark plugs. It also gives you the abilitly to advance/retard the timing by simply rotating the HES slightly on its slotted mounting holes.

 

When the wires short out, it just stops the electrical pulses to the motronic unit and it in turn can't fire the spark plugs. No sparky, no runny

 

Thats why they get so flakey. If we were relying on a legit ON/OFF voltage signal, then a failure of this type would most likely be a more permanent failure. A Hall Effect Sensor works along the lines of a proximity sensor, so it doesn't take much to screw with the signal.

[AndyS]

So what I am picking up from all this is, it isn't necessarily the HES, as much as it is the wiring degrading. Is that correct?

 

Yes......and no!

My R1150RT had a bad sensor.

Andy

[smiller]

With all the HES issues posted recently, including my own. If the HES powered wire shorted to one of the HES Signal wires, would it not, in this particular instance, harm the sensor?

There are electronics inside the sensor (output from the magnets is not adequate by itself, the signal must be amplified and conditioned) but most devices like this are designed to be current limited, meaning only a certain (and safe) amount of current can flow even if the leads are shorted.

[philbytx]

I found the Honeywell HES Specs HERE .

 

Note the components of the HES and the min/max temps......and the fact they do not guarantee the HES units performance "near" the temperature extremes!!

 

More grist for the mill eh

[eddd]

So what I am picking up from all this is, it isn't necessarily the HES, as much as it is the wiring degrading. Is that correct?

 

Yes......and no!

My R1150RT had a bad sensor.

Andy

 

 

It certainly can happen, but the vast majority of HES problems involve degraded wiring, especially an early model R1100RT.

[smiller]

Note the components of the HES and the min/max temps......and the fact they do not guarantee the HES units performance "near" the temperature extremes!!

The temperature ratings are still way above what they should see in any kind of normal service. I think we can consider them adequate given that the failure rate (of the pickups themselves) is so low.

[philbytx]

Seth, 150C is 302F...not outrageously hot. Just for my edification, next time I go for a decent ride, I'll take my IR thermometer and see what shows as a "normal" temp at this location.

 

I did a valve/TBS job on the R recently and it got a little hot, so I wonder if static temps get higher on the front engine block. Although I did have two Turbo fans blowing on the R oil coolers/cylinder heads but not focussed on the front of the motor.

 

Enquiring minds and all that

[smiller]

I remember sticking a temperature probe on the side of my engine a few years ago and as I recall the temperature was in the low 200's F. That's not the same location as the HES but the numbers shouldn't be too far apart. The cylinder head may run in the 300F+ range but I'd hate to think about your poor engine oil if the block ran that hot.