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Discussion in 'GS Boxers' started by wjrudo, Nov 29, 2012.
2.49K ohms right?
Zapped my dead strip last night with, tank off - alligator clips to a scripto lighter. Worked like a charm. Big TY.
Anyone know what those four wires actually connect to? The normal setup would be two capacitors: a small one at the very end (bottom of tank) that is always submerged, and which gets a baseline measurement for the dielectric constant of the gas; and the long strip, which actually measures the gas level.
In that setup, no wire is connected to any other wire -- or at least for DC measurements, which is what you're seeing with a voltmeter. The BMW setup must be different to explain why zapping would work, or why you'd have a 2.5 kOhm nominal resistance.
I saw the picture from the Haynes manual, but it's pretty clearly nonsense as it shows a variable resistor.
It is not a capacitive system. The outer pins are for a current to heat the strip and the inner two read the resistance above the fuel level (where it is still hot and not cooled by the fuel). Crazy process. The substrate fractures causing the failure. It would probably last forever if you could immobilize it but that would block the cooling effect of the fuel.
The strips of mine that broke (over 5 of them...different bikes over 5 years) did not fracture, etc. they became disconnected where the wires were connected to the strip. Inside a cube of some epoxy like substance. The failures seemed more like a questionable design or system of executing the design. I measured the strip resistance just under where the wires were attached and the strip was intact...and looked perfect visually as well.
The computer reads resistance of the total strip which varies with it's temperature. BMW's calibration procedure requires the strip to be dry in air and heated while the computer measures. Although I have not found that necessary. Simply replacing it has worked for me.
Yes same here - simply replacing the strip (with no re-calabration) worked perfectly for me as well.
Wow, that is nuts. Thanks for the explanation. That sheds a lot of light on this. With the exception of: why did they design it that way, when actual capacitive sensors work so much better?? Probably to save a few pennies, of course.
Change in resistance with temperature due to cooling a warmed strip. I never have determined if it is a positive temperature coefficient or negative such as a thermistor material. I have a spare...guess I could check it. But I think it's simple and would work flawlessly if the connections to the wires at the top were attached in a more positive way. I guess. I don't know why they disconnect, but they do. I would not discount vibration and corrosion internal to that epoxy like block with contaminants in the manufacturing process. I do not think that the fuel is playing a part since the connection is sealed in that blob of epoxy like material. And, the strip is pristine and unaffected as far as I can see and I have seen a lot of them.
As for capacitive, I have done that design and it is not as simple as this method I don't think. Generating an AC signal, etc. I know it is successful in bulk storage tanks and so forth, but I don't see how it would make this a more reliable measurement.
They have gone back to the float in '09 in the K13S and '10 in the GS and other bikes. My guess is that the float system is more expensive...anytime you have moving parts...and it of course measures resistance. The strip was supposed to be simpler and less expensive I think :).
Well, I was skeptical about a BBQ igniter fixing a fuel strip but I hid out in the garage today and removed my fuel strip. I gave it three shots with the igniter and voila ! My strip now tested with the same resistance as stated on this thread. I reinstalled the strip, started and stopped the engine three times to let the computer check and reset the fault code and now it shows 3/4 tank. This is a 2009 GS that I bought last year and the fuel gauge has never worked. Now we will wait and see how long it lasts. Thanks for the great tip!
My fuel strip was not working when I bought my 2009 1200GS in 2011 with only 1600 miles. Didn't know it at the time as I assumed it was simply low on fuel. Dealer replaced it under warranty in Oct 2011 and in June 2012 and in August 2012. Started running Startron Enzyme Fuel Treatment at the recommendation of another dealer and it allowed me to get through the rest of the season. But when I started it this year, after sitting with a nearly empty tank of treated fuel, the gauge worked for a few seconds and then the light came on. My warranty expired in Nov, 2012 and my dealer had told me I would have to pay for the first out of warranty replacement ($200) and it would be covered for 2 years after that. Even though I just had it replaced in August!
I tried the grill igniter zap Sunday with the strip in the tank and not much fuel. Hit the button 3 times and then checked the resistance and it appeared to be good. Rode it to the gas station with the gauge still reading zero and the warning light on, and was nervous. But a mile or less down the road from the gas station - it started working!
Big thanks go out to jzeiler for this discovery - you're a genius! Maybe you should go get a job in the BMW Engineering Dept!
If a repair is made during the vehicle warranty period, BMWNA warranties the repair for the remainder of the vehicle warranty or 24 months which ever is longer.
Well that's some good information! I knew my Service Manager was an underachiever. I dropped the bike off just before noon and my 2 he didn't even remember who I was! Sounds like I am good either way for another year plus. The BBQ igniter saves me 100 mile round trip - which isn't near as bad as the frustration of dealing with an inept Service Mgr.
Thank you for the heads up!
My 2010 GSA consumed its 2nd fuel strip. No longer having a local dealer, I thought I would try zapping the fuel strip into submission. To my surprise... it worked! First I checked the resistance across the two center pins... nada. Zapped the center pins a few times with the Wally World grill igniter. Checked resistance a second time, 2.8 ohms! I turned the ignition on allowing the check cycle to commence. The waning triangle and FUEL warning remained. Started bike and after a few moments the warning went away. Success!
To allow for easy access to the pins, I utilized some mini test leads that easily slid over the pins and attached some mini clips to the igniter.
Some pictures of the setup.
I love this. Been reading it for a long time.
Sorta makes BMW engineers look bad. I just bought a 2012 R1200R with a working fuel strip in September. I have been reading about these for quite a while.
Glad to see so many have been repaired.
Actually restored to 2.8K ohms not 2.8 eh? I think the suppliers did this fuel strip thing to BMW and they're as much the victim as we are. Only thing is they won't buck up and campaign the damn thing like they did on the antenna ring which had almost the same issue of no contact inside.
I guess the antenna ring had all those bikes coming back on flat bed tow trucks...lots more money involved than just we walking to the gas station for a gallon of fuel.
But it's not just a walk to the gas station. I ran out of gas on the freeway at 75mph, in rush hour traffic. It was dangerous trying to pull to the side of the highway right where another highway was merging onto the highway I was on (just my dumb luck where I ran out). With no power it was a pretty scary few moments trying not to get run over by a couple of semi trucks going full speed and honking their horns while I kept going slower and slower. Stupid me for trusting my gas gauge. I figured it was correct because the strip was replaced just a couple weeks before and my first one lasted 2 years. I'll never trust the gas gauge again, I only use the odometer now and even then fill up when I think I'm down to 2 gallons or so.
BMW should start this damn recall now before someone gets killed. They need to come up with a real solution. It's complete bullshit that they just ignore the problem.
Jeez! Glad you're okay!
The initial zaps with the igniter last month did turn off the warning light and, after refueling, allowed the gauge to read full rather than empty.
But after a couple rides, I noticed that I seemed to have infinite fuel capacity, i.e., the gauge was not dropping below full.
So the other day, I zapped it again!
Lo and behold, on yesterday's ride, the gauge showed half full and the range counted down rather quickly to a reasonable number! Seems to be working fine again!
Keep your zapper handy!
Interesting that the solution to the fuel strip problem seems to be attaching an igniter to device in a fuel tank.
2500kms and still going strong!