BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

I finally got my bike back from the shop after a week in. Don't get me started about my local dealer... Anyway, the bike died at an intersection on the way home from work and I got a tow. (Hour and a half wait in town after calling BMW). My initial failure indicated a bad fuel pump (per GS-911) and it matches the symptoms. Only 150 miles on a full tank, fuel gauge has been working and still indicated fuel, no warning lights, tries to start but indicates lack of fuel. I get the bike back and the dealer ran through a barrage of tests and came up with yet another bad fuel strip.

Less than 1k miles on my 2010 R1200R and this is the second fuel strip. The first was replaced after the bike constantly read empty. I've read of other failures here on the board, but multiple failures? I'm planning to make some long runs next month, but at this pace I'll go through two more fuel strips before I can get to Texas. Anyone up to three replacements yet?

Mine's been fine on the R, same problems on my GS though.

My fix that doesn't involved any stress from continuously poo dealers:

reset trip odometer at fuel up.
refill around 150 miles.
ride happy.

I'm on my fourth. At least this one registers but is nowhere near correct. I never rely on it. And unless it totally breaks, I'll never let them screw with it again. I've put on 20,000 miles - no other complaints (except orig. battery, of course). I think it's a great bike, and I love riding it.

I have had my R12 is about 2 years, about 12k miles. 4 fuel strips. When I got it from he dealer the strip was bad. I always use the odometer, but when it goes bad showing empty (it has also been bad showing full) the low fuel light is on and is annoying. I asked the dealer if the low fuel light could be disabled, unfortunately no.

Sounds like another failure is to be expected. I've been going old school with the fuel indication since the last failure- depending on the odometer instead of the fuel level indication. I have to do this with my Duc anyway since the low fuel light doesn't even work on it. Has anyone else been stranded by a failure of the strip, except from running out of fuel? My last failure caused the fuel pump to shut down, and the fuel indication was still working.

Maybe i'm lucky, but no failures to report yet.

How big a deal is it, i.e., what does it cost to replace a fuel strip?

vroomr wrote:How big a deal is it, i.e., what does it cost to replace a fuel strip?

Nothing under warranty. The fuel strip is part number 16147697815- about $171. Labor for troubleshooting and repair was 1.8 hours. I was stranded for 1.5 hours on the side of the road (no, I was not out of fuel- the bike wouldn't run). Towing was free, although the shop was closed by the time the truck got there so I had to get towed home and then trailer it to the shop. My bike was OOC for a week. I'm still trying to figure out how 1.8 hours = 7 days. Perhaps there is a shortage of fuel strips as I've already been through two in the past few months...

Are you saying the the defective fuel strip caused the fuel pump to stop? Whoa. It's one thing to get a bad reading, quite another to have fuel you can't use because of a defective gauge. Yike.

vroomr wrote:Are you saying the the defective fuel strip caused the fuel pump to stop? Whoa. It's one thing to get a bad reading, quite another to have fuel you can't use because of a defective gauge. Yike.

It seemed strange to me, but I reset the code with the GS-911 and it came back. Fuel pump failure. The shop had to reset some leak-something-or-other to clear the pump code. Apparently traced it back to the fuel strip. Weird...

Is weird..

Had mine (first) replaced today.. at 35,500 miles. It had gone bonkers a few weeks ago (see other thread on that), then after a tank with a dose of Techron in it seemed to recover. I asked them to save the old strip for me. We (dealer shop) had another defective strip, and they had never taken one apart.. so we did.

Inside the strip is a piece of flexible clear plastic, probably about 0.010" thick. It has a metalized pattern on both sides in a tight zig-zag pattern, with another solid trace connecting the bottom of this pattern to the top connector. There are four leads coming out, one each for the zig-zag patterns, one each for the return conductors. The zig-zag is a classic resistor type sensor, and it appears (based on some knowledge from designing these sort of things) that they are part of a classic bridge sensor circuit. Voltage flows through the resistor, usually at a controlled voltage. The current flowing through the resistor will directly change with the resistance of the resistor. The current/voltage flow tends to heat the strip a bit. The portion of the strip that is immersed in fuel is cooled by the fuel. The portion above the fuel isn't. This changes the resistance of the strip - which changes the current draw as the fuel level changes.

For more on the engineering see: http://www.doctronics.co.uk/voltage.htm#temperature - look for the one discussion on "The thermistor sensors are part of a Wheatstone bridge:"

Anyway - what fails? We looked carefully at the strip and the only oddity we could see was what appeared to be a kink in it. The strip is supported within a curved strip sort of housing that is designed to match the wall of our fuel tanks (and fit into a clip at the bottom of the tank.) It doesn't seem as if the strip could actually kink, and the strip is well protected in the housing (a small slot on both sides exposes the zig-zag resistor in a narrow slot.) The kink may have been caused when we disassembled the sensor, or perhaps if somehow some shorting occurred - it might have been caused by heating. If this was where the flaw was (I wish I'd asked to take it home so I could check it with an ohmmeter over it's length) - this would mean the system wouldn't be able to read anything below that point on the strip. There was no obvious fuel attack on the strip or the metalized pattern, and all the wiring seemed intact (but really unknown without an ohmmeter test.) People had theorized (on other forums) that failure might be caused by directing the gasoline fill flow right at the sensor strip - but looking at it - I would doubt if that would cause damage. If you want to make sure - just point the flow at the right side of the tank (fill from the left.)

So - dunno for sure what fails - but do at least have an idea how it is made. If anyone has a bad strip kicking around and wants to send it to me - I wouldn't mind doing some more intensive examination on one.

Oh - my new strip seems to be working fine. Replacing it does require draining the fuel tank, and quite possibly calibrating the sensor to where you want the warning light to turn on.. the dealership filled my tank when they were done, and the job was covered under warranty. Hats off to Cross Country BMW for the great service!

This is truly a case where YMMV..

One other thing - the service writer and service manager said the reason people may get erroneous miles until empty readings is - they haven't reset their average MPG/Speed. They said their GS owners manual (later model bike then mine) suggests it be reset at every fillup. So - really - YMMV..

Mine failed this morning.

I had one replaced a few months ago. The new one read about 1/4 tank when I got stuck on the Garden State Parkway about an hour ago. Thank God my buddy was with me, he went to a gas station bought a can and brought me some fuel. Filled it up and off we went. From now on the trip odometer shall be my fuel gauge.

Thank you Don for the detailed insight. As an ex-Navy IC, I've worked with several tank level indicating systems but have never seen one quite like this. I prefer the old reliable float and magnetic reed switches. I wonder if this is one of the parts BMW is sourcing outside Germany...

dumfounded wrote:Thank you Don for the detailed insight. As an ex-Navy IC, I've worked with several tank level indicating systems but have never seen one quite like this. I prefer the old reliable float and magnetic reed switches. I wonder if this is one of the parts BMW is sourcing outside Germany...

I guess so - but not far from Germany.. inside it was "Austria" - so I'm guessing that was where it was made. It looks well made, looks like a good idea.. but as an old friend says "Between theory and practice reality intervenes." I think this seemed like a great idea, no moving parts, all electronic - what could go wrong? Probably seemed like that the first time BMW did it in 1983..

My first one failed at around 1000 miles.
I'm at about 3000 miles now with my second. No problems so far.

deilenberger wrote: One other thing - the service writer and service manager said the reason people may get erroneous miles until empty readings is - they haven't reset their average MPG/Speed. They said their GS owners manual (later model bike then mine) suggests it be reset at every fillup. So - really - YMMV..

Thanks for the tip, Don. My computer seems to read fuel / miles to empty OK at times and quite wonky* at others. I'll try the reset option and see if that improves consistency (but I'll still use the trip meter!).

I'm on my second strip. The first didn't work at all (replaced under warranty). When the second gave wonky* readings I stopped fussing and went back to using the trip meter. I smile when it works, or seems to, and forget about it when it doesn't work.

I've never trusted fuel gauges on bikes - IRRC they first appeared on the K1100LT, but none of us with those in my BMW club relied on them - always reset our trip meters. The F650CS' low fuel light came on a steady 100km km before empty (DAMHIK - twice! ) but I still used the trip meter. I figure bike fuel tanks are so small compared to cars that the resulting error margins are too large for any fuel gauge to be seriously accurate, much less reliable away from towns (I regularly plan routes with 150-200km between easy fuel options).

(*tech term)

After decades of biking I always set the tripmeter, and that's what I look at. I still miss having that petcock reserve, though! Using the tripmeter, always remember that mileage varies with speed. I got 63mpg over about 60 miles, following a buddy who was towing at 55/60mph, and 27mpg at a steady 90mph (or was it 100?). Anyhow, one day the "low fuel" light went on about 25/30 miles north of town, so I turned around and zoomed back at 85mph, without thinking of how fast I was sucking fuel. I ran out 1 mile and 2 hills short of the first gas station, and I got some real good exercise pushing her in. Serves me right for not taking it easy!

ChiTown wrote:reset trip odometer at fuel up.
refill around 150 miles.
ride happy.

Words to ride by in urban stop-and-go.

I had mine replaced under warranty about 3 weeks ago. I always use my trip odo anyway. But I figured since it was under warranty I may as well go for it. I had about 10,000 km on the bike

Celeste