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Engine cuts off- intermittently


Aviationmx

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Aviationmx

99 1100rt 55K miles

 

Experienced the engine cutting off 4 times last week, it would restart after 2-5 minutes. Bike was caught in the rain last week and i removed the relays and let the fuse box dry ( it didn't seem wet) as a precution.

 

The bike ran for 60 miles w/o an issue until today, cut off twice and started back up after 30 sec.

 

Finally caught the fault on the center stand. RID and neutral light on, tech erratic. The fuel pump cycled several times and it restarted.

 

I'm guessing the stand switch is fine and except for tech i was ruling out the HES ( original, as far as i know).

 

I tried moving the relays and fuses- no change. But it did seem to be a short of some sort. I checked the Batt cables and swung the front wheel w/ no change.

 

Any gremlins in the elect system I should check first? the fuel pump cycling on / off would indicate it's not the HES system, correct?

 

~chris

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Aviationmx

Ok, I think i found the issue...being an X avionics specialist- I'm a professional wire wiggler. While running, i was moving the wires under the fuse box and got the engine to start to cut off.

 

I check the connections and fuses/ relays...

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Danny caddyshack Noonan

Another location for that is the harness just below the steering head.

 

The rain cutout is often also a sign of a bad HES harness.

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Aviationmx

Well, the bike ran great for about 40 miles and cut out again, this time for about 15 min before restart.

 

This time it the clock reset and the fuel pump cycled on and off when i tried to restart it. Once started it made it 5 miles home.

 

I would like to trouble shoot this and isolate the issue, but i may just have to do the HES anyway, to remove the possibility and for future possible failure. The only thing i was concerned about was the coil may be the problem, but I try to duplicate the problem and will check for power to the coil before pulling the HES.

 

 

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Danny caddyshack Noonan

I would like to trouble shoot this and isolate the issue

 

I'm the same way.

 

Maybe strip the bike down. Run it sitting still with a big fan blowing on the front. Then play with harnesses that you can get to. In that configuration, you can remove the tank bolt in back and move the tank around being careful to watch the fuel and vent hoses for binding and such.

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Afternoon Aviationmx

 

Exactly when did the clock re-set to 00:00?

 

That might tell us a lot about your problem right there.

 

If the clock reset at the same time as the bike quit then you probably have a massive system power loss (like a loose battery cable or problem at the fuse box area).

 

If it re-set while cranking the engine trying to re-start it then the clock re-set is probably a meaningless occurrence.

 

You might want to check or by-pass your side stand switch as that could be the cause of the sudden engine quit (won't effect or cause the clock to re-set though)

 

Or as you mention just replace the HES as a precaution & get that out of the stalling equation.

 

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99 1100rt 55K miles

 

Experienced the engine cutting off 4 times last week, it would restart after 2-5 minutes. Bike was caught in the rain last week and i removed the relays and let the fuse box dry ( it didn't seem wet) as a precution.

 

The bike ran for 60 miles w/o an issue until today, cut off twice and started back up after 30 sec.

 

Finally caught the fault on the center stand. RID and neutral light on, tech erratic. The fuel pump cycled several times and it restarted.

 

I'm guessing the stand switch is fine and except for tech i was ruling out the HES ( original, as far as i know).

 

I tried moving the relays and fuses- no change. But it did seem to be a short of some sort. I checked the Batt cables and swung the front wheel w/ no change.

 

Any gremlins in the elect system I should check first? the fuel pump cycling on / off would indicate it's not the HES system, correct?

 

~chris

 

An erratic tachometer, with the needle bouncing around is a classic symptom for a bad HES harness. the Tach gets its RPM information from the HES, so if the signal is noisy from a shorted harness it reads all over the place.

 

Andy

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Aviationmx

Thanks all,

 

I'll strip it down and check for loose power/grounds...but w/ the info that the tach impulse comes from the Hall Sensors pretty much points to the HES. I would assume if the loss of power would just put the tach at 0 and wouldn't make it jump at 2-5k indicated.

 

Chris

 

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I think you're on the right track, the fact that the clock reset means it is a main power issue and not a throttle cable or bad fuel tank venting.

 

Recheck the battery cables. Even when it feels tight when doing a fast check by hand, a wrench will still be able to tighten it more and that eliminates a bad connection.

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Morning Chris

 

When did that clock go to 00:00? If during the engine cranking part then probably not a telltale sign of anything but a cranked-low battery.

 

Even the tac acting strange could be an indicator-- (definitely the tac can act up with a failing HES).

But also keep in mind that-- (IF) you have a loose battery cable or bad wire connection the alternator will try to keep the electrics alive (including the tac) so as the RPM's fall off the tac power can start to fluctuate & cause needle oscillation.

 

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Aviationmx

DR,

 

Clock reset once after the engine cut off about 5 times.

 

Batt cables are tight and don't show a short and ground looks good. pulled the tank and the alt belt cover, and was trying to follow the cable from the halls sensor up to coil/ignition control.

 

On the r/h there is a 4 pin plug, just above the throttle body...the plug is cracked and some the pins are loose and dirty. It has a brown ground wire and a yellow/green / white thin gauge wires w/ tracers.

 

I'll try to ID the plug from the wiring diagram

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Afternoon Chris

 

That might be the 02 sensor plug.

 

Are the wire colors 2 brown wires, one yellow wire, & one green with white tracer?

 

An 02 sensor acting up can cause an engine stall but not the clock re-set & not normally the erratic tac issue.

 

If it is the 02 sensor you can just unplug that or remove the CCP & run your bike with no active02 sensor to see if that is/was your issue.

 

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Aviationmx

The plug has brn for ground, grn/ white,white/

Blk and yellow/purple. But I think your right about the O2 circuit.

 

The CCP has been removed for maintenance purposes...lol.

 

I've run the HES circuit and nothing seems broken down, tried to'move the wires at the alt when running but no fault.

 

Bike has been run for about 30 min, off and on, and no faults...

 

Guess I just R and R the HES this week and se what happens

 

 

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Aviationmx

Had the bike warmed up for over an hour and drove, around the neighborhood, for about 20 min...no issues. And I did have fans on the cooler while in the garage, never came close to over heating.

 

I wished I had checked the cracked plug before I cleaned the pins/sockets. But it has a 1/4 inch piece missing right over the ground wire and it was pretty dirty inside the plug.

 

I know the HES wiring is critical behind the pulley, but the wiring that is exposed running up underneath the Alt is intact and I couldnt get the engine to cut off even when I moved it around.

 

If it was an HES fault from the wiring, wouldn't it fail at temp within the hour it been running?

 

So I'm going to take it out for a longer ride at speed, if you don't hear from me, I'm stuck somewhere on Highway 150 near summerfield NC.

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----

 

If it was an HES fault from the wiring, wouldn't it fail at temp within the hour it been running?

 

 

Evening Chris

 

HES failures are usually due to moisture entry into the wire harness down near the HES plate.

 

BUT!, like about any other electronic unit heat could always be one of the factors in it's acting strangely.

 

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Aviationmx

Evening DR,

 

I put about 60 miles on the bike and no issues, not a hiccup.

 

I need to chase down the wires on the plug that was damaged to see if that is the connector for the HES, but i did see a picture of a 4 pin plug on "how to r/r the HES" that looked the same and was at the same location ( under the fuel tank r/h side)as the one that I cleaned.

 

If that's true or if that ground in the plug is used by the HES system, you have to wonder if maybe when a new HES is installed , it may just be a new plug and not the wiring that fixes the issue. Obviously, if the wires are baked at the Hall sensors, it's a good fix but if it's just the poor connection at the plug...

 

In any case, thanks to you and others for letting me talk through this little exercise. Hopefully it won't return, and i can pocket the $200 for a new HES plate.

 

Chris

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roger 04 rt

Hi aviationmx,

 

For your clock to be reset, ground or power going to the Clock had to be interrupted. That could be a break that still touches, a wire loose in a crimp or a lug loose at its bolt. As you already know these can be hard to find.

 

The problem with intermittents is that they always return. Maybe you'll do some repair work to the HES and won't have the problem for a while or you'll clean & repair that connector you describe and it will work for a while. But the clock resetting is unrelated, I think.

 

If you want peace of mind, trace the power and ground from the Clock all the way to their terminations at the battery or common point. The clock wires don't need the key switch, so that is a help. But if you trace them you should find the point where one of them is in common with the Motronic or the fuse box or the relays.

 

Like you, I ride an older bike, and the wiring does get damaged. If it were me I would want to find the intermittent rather than have it find me at the wrong time or place.

RB

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Morning Chris

 

 

It has been a while but BIIRC the HES connector is a 6 cavity plug with 5 wires in it.

(orange, red, black, brown, shielded).

 

 

 

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Aviationmx

Good points,both.

 

I'll hope I had a different set off issues that where directly related to the connector I repaired...perhaps the connector has a set of reference voltages for the ignition system or a floating ground that just causing a problem. But quite correct, 60 miles of trouble fee ops doesn't make for a definitive repair. I'm new to BMW and still have a ways to go understand the wiring philosophy,although I have experienced working on lucus due to 70 mgb-now there's some interesting electrical theory and application.

 

And I certainly don't want to be stuck anywhere, so I'll prob dig back into my pockets or look for a used set of sensors to rewire...The Halls effect: when $200 is worth spending to fix a potential problem...and i would like to put my fairings back on at some point. But this is part of owning an older bike, I just assumed it would run forever w/o any issues... ;)

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Galactic Greyhound
99 1100rt 55K miles

 

.......Any gremlins in the elect system I should check first? the fuel pump cycling on / off would indicate it's not the HES system, correct?

 

~chris

 

Not correct Chris, the Motronic starts the fuel pump to prime the fuel rails at Ignition 'On' and then stops the pump until it receives fuelling pulses from the HES bottom (180 deg)sensor when the engine is turning. The HES top (TDC)sensor sends ignition pulses to the Motronic when the engine is turning so that it can work out the ignition timing. A faulty HES can therefore affect the fuelling and/or the ignition.

 

Mine went on my '96 R1100RT last year for the first time after going through a flooded road. The bike eventually re-started to get me home but on later testing, when the oil temp reached 2 bars, the ignition always cut out. I replaced the HES and all has been well since. HES sensor repair here:

http://advwisdom.hogranch.com/Wisdom/oilhead_hall_sensors.pdf

 

The HES connector is zip-tied on the RH side of the bike, by the Motronic unit and is covered with a thick white(ish) plastic sleeve which is crimped to the cable at the neck. You need to warm the sleeve slightly and slide it up to better access the HES connector - don't try and remove the neck crimp, slide the bottom part of the warmed sleeve up and over it. You can see the sleeve here (thanks to Limecreek's photo archive) on the 3rd photo, January 3, 2011:

http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=667537&page=1

 

At the rear of the tank, clipped to a frame mount on the RH side, is the 4-way connector for the fuel tank plate (pump, low-level fuel light and fuel gauge sender tube). The main loom side wires on this connector are coloured; 1- Brown (frame ground), 2- Green/White, 3- Yellow/Brown, 4- White/Blue.

 

LATER EDIT: You can run the bike with the two side fairings removed without any issues as long as you refit the mirror pods. This way you can fully test and use the bike without the hassle of having to remove the fairings.

 

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Morning Chris

 

Until you identify that connector & get a reoccurring reproducible engine stall you are kind of shooting in the dark.

 

Difficult to tell you what you need to do as your next move.

 

If it were MY bike & seeing that it is an 1100 I would definitely rebuild the HES as long as the plastic is off & I was chasing a problem that COULD be tracked back to a possible HES problem.

 

The 1100RT's don't have a lot electrical issues but a failing HES is one that can & does occur on a good number of BMW 1100's.

 

Even if the HES is not the immediate problem it sure could be an issue in the future. The HES is a lot easier to deal with in your home garage than on the road at 1am in a rain storm.

 

 

If that broken connector is the 02 sensor there is only about one possibility that should hinder a restart.

An open should just be ignored by the Motronic so no starting issue there.

As short to ground should again be ignored by the Motronic at least until the system has been running long enough to look for 02 input.

 

The last is a power bleed off from the 02 heater circuit into the sensor high circuit (even a bit of moisture in the connector can cause that). Over the years I have seen a few with moisture in the connector causing a very poor running engine & lots of stalls but can't remember seeing it hinder the re-start, but that might be a possibility.

 

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Aviationmx

Ced ID'd the plug, it's fuel pump and associated fuel quality sensing circuits. It's possible the fuel pump was losing ground from the dirty ground in the plug. There is no doubt the plug had little integrity and was collecting water and may explain the fuel pump cycling on/off when the engine would shut down.

 

But it's just a guess, I'll ride some more to see if it cuts out again, I'm not sure why I have to tempt fate except that I want to see if that was the issue I confused w/ the HES.

 

But i will stop taking up any more time and will replace the HES for peace of mind, especially after reading several stories of R&R the plate in parking lots, in the rain...etc.

 

In the end, $200 is a small price to pay for riding such a great piece of engineering, even if it surges a bit and has crappy wires on the hall effect sensors. i still can't get my head around the autolite spark plugs in a German bike...from Wally world.

 

Thanks all and have a great memorial day,

 

Chris

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Afternoon Chris

 

The fuel pump & fuel gauge sender both use the same ground in that plug. You would think that if the fuel pump ground was acting up the fuel gauge in the RID would have gone crazy due to loss of it's ground.

 

Possibly the green wire (#2) terminal was losing contact as that would kill the pump without effecting the fuel gauge.

 

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roger 04 rt
...

 

even if it surges a bit

 

...

 

Chris

 

Chris. Glad to hear you're working out the electrical issue. I don't plan to hijack the thread but your bike doesn't have to surge even a bit; and it can have a strong mid-range too. RB

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Aviationmx

RB,

 

I've ran through the TPS/Throttle Sync/Spark plug ritual to have a small surge of about 150 RPMs. I've recently pulled the CCP to try to limit the ignition control's ability to seek the pre determined engine performance profile...if i understand how the engine management system works. I like the richer mixture and there more power available- I'm not too happy about additional pollution or that my CAT may clog. But I do like a happier engine, she's 13 yrs old now and it's a reversible change.

 

The surge is not noticeable in the longer gears, so I'm quite happy with the set up. I've left the canister intact at this point.

 

D.R.

 

I think you have it right, I just had a broken connector that was shutting down the fuel pump or a ground that was causing havoc, i didn't notice the RID losing power,but I think I was projecting an HES failure indications on my observations ( watching the tach or even the neutral light when it died). I've added another 50 miles, for a total of around 120 miles w/o issues- I'll take that as a success for now.

 

Question: I have the hardest time removing the pulley cover on the front of the engine but have seen that some folks have cut the cover in half to slide it out easier- any thoughts on how to do the mod w/o having more H2O enter the HES area? is that not a concern?

 

If I've just hijacked my own thread, let me know...the knowledge base here is huge and I can't resist soaking up D.R.'s and others advice.

 

And I would like to thank the Scotsman (or his galactic dog) for identifying the plug in question. It would nice to have a connector schematic by location for troubleshooting. And now that I know where the Hall's sensor connector location, I may be able to T shoot from there next time.

 

~Chris

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----

 

Question:----any thoughts on how to do the mod w/o having more H2O enter the HES area? is that not a concern?

 

 

Morning Chris

 

It concerns me.

 

On cutting that front cover. Some do, I never have & never found I needed to as the front cover removal isn't a big deal once you get the hang of it.

 

 

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