Wet Weather Problems R1100RT

[Old Sport]

Recently I was caught in an unusually heavy rain storm (3 inches in 3 hours). My bike was performing flawlessly until I hit the rain. After about 2 miles of riding in the rain it cut out then went dead. It restarted and I went in search of shelter after another mile it went dead again, restarted ran a few hundred feet and died. It has not started since. I have checked all fuses, everything seems to be operating normally at start-up. All switches seem to be working, side stand, kill, neutral, and so forth. Fuel pump hums normally at start-up and the starter turns the motor normally. I am not getting fire at the plugs. The coil shows no sign of damage and checks out normally. Actually the secondary resistance reads 7.3 K and the Hayes manual says the reading should be 13 K for the 1100RT and 7.5 K for the 1150RT. The local shop says that the coil is the same part number for both bikes. None the less I am getting no spark at all. I have checked the HALL sensor with an led and it seem to be functioning normally top and bottom. I am at a loss and would be thankful for any helpful input. Thanks.

[dirtrider]

Morning Old Sport

 

Your problem has all the hear marks of a failing HES (hall effect sensor). That resides behind the engine front belt pulley.

 

The HES is what the fueling computer uses to tell when to spark the spark & inject the fuel at the proper timing.

 

On the BMW 1100 the HES sensor itself is usually OK it's the wires between the sensor & the fueling computer that degrade then allow moisture to short them out. (very common problem on older BMW 1100's)

 

You have a couple of choices:

 

One- is to just install & properly time a new HES sensor (expensive).

 

The other is to remove your sensor & re-wire it using high temperature wiring (that usually cures the problem)

 

You can search the archives on this site for MANY HES failures on the BMW 1100. Unfortunately the search function can not use only 3 letters (must be at least 4). You can try searching for "hall effect sensor" using the quote marks as shown.

 

[Old Sport]

I downloaded a repair sheet and made the led tester. The sensors seem to be functioning correctly. The bike will not start even after cool down.

[OoPEZoO]

I downloaded a repair sheet and made the led tester. The sensors seem to be functioning correctly. The bike will not start even after cool down.

 

That "tester" doesn't tell you much of anything in the real world. It makes sure nothing is physically shorted or open in the circuit, but it can't replicate the actual scenario of the bike starting up. The insulation on the wires breaks down and the wires begin to arc between each other. They don't usually physically touch and/or short. I have one sitting on my tool box that tested out good as well, but it also let me sit on the side of the road 300 miles from home the day after riding in a driving rain storm.

 

My vote also goes with a failed HES. DR pretty much covered your options.........buy a new one, or rebuild the one you have.

[dirtrider]

Morning Old Sport

 

It still sounds like your HES but I'm not there working on it so that is just an educated guess on my part.

 

So, ASSUMING your HES is working properly & is not only able to pulse an LED but is also able to supply the PROPER signal to the Motronic to allow it to spark & inject properly then lets move on.

 

Not knowing how or what you have tested- lets start from the beginning--

 

First- take a "known good" spark plug (doesn't have to be for your engine) then open the electrode gap to 3/16" (use a 3/16" drill bit as a gap gauge). Now install that special plug in one of the plug wires & lay on the cyl head or engine block (leave the original plugs in the engine for cranking load). Now crank the engine & see if you get a bluish colored snappy spark across that 3/16" gap. If wimpy, yellowish, or not snappy you probably have a weak spark. Could be due to the HES, or low power to the coil, or low cranking voltage, or ??????

A spark jumping across the stock spark plug electrode gap cranking with plugs removed doesn't tell you enough about the spark intensity to be real useful.

 

Next- remove one of the fuel injectors (very carefully so you don't break it). Then with the wire & fuel line still hooked up place the spray end in a bottle or jar & crank the engine over. Do you get a nice strong spray at as the fueling computer triggers it? If not look into the HES or low fuel pressure (like broken hose in the fuel tank) or an engine sensor issue. Maybe do a fuel return hose test to see if you are getting a decent fuel flow from the fuel return hose while jumping the fuel pump relay. If no return fuel flow you have very low fuel pressure (maybe not enough to run the engine)

 

OK (IF) you have the above good bluish spark & good injection from one of the injectors then look into water in the fuel system.

It could have a degraded water drain hose from the fuel cap area (drain hose runs through the inside of the fuel tank) or engine purge vacuum could have sucked water up from the vent system, or if the Evap can has been removed it could suck water in through the tank vent hose if it was hanging low behind the R/H foot peg & not cut at an angle.

 

If you have A GOOD BLUISH SPARK, GOOD SOLID FUEL INJECTION, & clean water free fuel then post back & we can go into other mechanical or electrical areas.

 

 

 

[philbytx]

+1

 

For a new (or repaired!) HES......

 

 

 

[roger 04 rt]

When the HES is suspected, why don't we recommend reading the Motronic fault memory?

 

Here's a link to how with codes: R1100 Fault Codes (Largiader's Site)

[dirtrider]

Afternoon Roger

 

I'm not sure that will tell you much on the old Ma 2.2 system. I haven't found those failure codes to be very reliable on the Ma 2.2 system.

 

The Ma 2.2 failure codes are pretty iffy on partially working things.

 

If you un-plugged the sensor & tried to start it you would probably get a failure code or codes. With it plugged in & only having cross talk it might & might not show up. I have seen both 1122 & 1123 trapped on good working systems after a stall.

 

Might not hurt to check the codes but I sure wouldn't replace a sensor on either an 1122 or 11123 showing & definitely wouldn't say the HES is good with no codes showing.

 

[Old Sport]

Ok you convinced me. I am going to order a replacement HES, then try to repair the one I have as a back-up. Ouestion, will I need to retime the engine when I replace the HES?

[dirtrider]

---- Question, will I need to retime the engine when I replace the HES?

 

Afternoon Old Sport

 

In a nut shell Yes--

 

Some just mark the position of the old one then try to match up the markings when they install the new one. This works best if ONLY removing & repairing the old one, not so good when installing a new HES.

 

To do it correctly just mark the original HES position, then put the new on as close as possible, then set the final position by the flywheel timing marks (you already have the LED HES tester set up so that should be easy). Or use a timing light (works on the 1100 not so good on the 1150).

 

[philbytx]

Go HERE for great service and good pricing on an HES.

 

As per D.R.'s post. When I R&R'd my HES, I marked the position using an indelible marker, installed the new HES by lining up with the marks and then used my timing light box to verify the timing.

 

Not a difficult job at all.

 

 

[Old Sport]

Thanks Guys! Ya'll are the best. I made a different tester from a different page I found and ordered a new HES sensor. Removed the old sensor and checked it with the new tester. video link below.

 

 

Installed the unit and used new tester to set the timing. Bike started right up and runs perfectly. From diassembly to reassembly about 4 hours. I am so pumped. I learned so much about the bike and found some really cool and informative resources for the RT. Not to mention I saved about $300 on the repair and another $200 on the tester by making it myself. How lucky are we to have the internet!

[Old Sport]

HES Test box

 

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

[SKYGZR]

Yet another "CARRY A SPARE and the TOOLS and KNOW HOW to CHANGE IT" story...

[Old Sport]

One more quick question. I was finally able to take the bike for a longer ride yesterday. I had only been getting around 40 mpg up to this point. On yesterday's ride I got 46 mpg. Is that probable or am I miscalculating? Would the new HES effect fuel consumption? I have begun rewireing the old unit and the wiring was so bad I am amazed it was even running.

[Michaelr11]

I would love to see some photos of the old wiring faults and the rewiring job you are doing.

[Old Sport]

I would love to see some photos of the old wiring faults and the rewiring job you are doing.

 

Link to Instructions for removal and repair,

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

 

 

Starting to explore the unit wires look OK.

http://i813.photobucket.com/albums/zz57/Execpriv/BMW/Hes1.jpg

 

 

Cutting in you see wires have become brittle.

http://i813.photobucket.com/albums/zz57/Execpriv/BMW/Hes2.jpg

 

 

Cutting away more wire insulation has decayed all the way to the

wire tab on the engine.

http://i813.photobucket.com/albums/zz57/Execpriv/BMW/Hes3.jpg

 

 

I checked the individual sensors and they seemed to work correctly.

So I ordered a multistran 22 gauge shielded high temp wire from McMaster Carr. 3 ft. was $12.00

http://i813.photobucket.com/albums/zz57/Execpriv/BMW/Hes4.jpg

 

 

Reassembled unit with High temp shrink wrap on the out side,

http://i813.photobucket.com/albums/zz57/Execpriv/BMW/Hes5.jpg

 

 

The wire bundle maybe a little large but I won't know until I attempt to put it on the bike. wire colors are off from original, but when plugged into the tester seems to function perfectly.

http://i813.photobucket.com/albums/zz57/Execpriv/BMW/Hes6.jpg

 

This was what I would term a difficult procedure. I was surprised by the wire condition and that the bike was running at all. It was actually running really well before the hard rain. I hope the new sensor last as long as the first, 12 years. If so I may never need the backup. Overall I spent a little less than $300 on this repair. Less than the part at most places and I learned a ton in the process of doing it myself. Thanks again guys.

[SKYGZR]

Now you have to take out the "new" one, and reinstall your rebuild to make sure. Carry the "new" one at all times if the reworked one works!!