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Author Topic: Gas sender fail - '07 RT1200  (Read 254 times)

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Offline RBEmerson

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Gas sender fail - '07 RT1200
« on: October 30, 2019, 11:20:25 AM »
A friend with an '07 RT1200 is, again, stuck with a failed gas tank level sender. It was replaced under warranty. The current sender lasted longer than the others before failing.

I wonder if it's the sender/sensor that's failing or wiring wearing through.

Does anyone have an insight into what's happening here?
Are you part of the solution or part of the precipitate?

Online Black Hills

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Re: Gas sender fail - '07 RT1200
« Reply #1 on: October 30, 2019, 11:42:54 AM »
Germans....
the above are merely the ramblings of a hamfisted fuckwit who has broken too many helmets.

Online leeo45

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Re: Gas sender fail - '07 RT1200
« Reply #2 on: October 30, 2019, 12:59:46 PM »
I am pretty sure that model has the notorious BMW Fuel Strip mechanism in the tank rather than a traditional float.   BMW extended the warranty on these to 12 years because they continually fail.  They never provided a fix, just a warranty replacement with the part that is known to fail.   It is the microscopic resistive wires in the flexible strip which fail, nothing mechanical and nothing in the regular wiring harness.   

My 2007 GS Adv has been through five (six if you count the one that was DOA when the dealer installed it).   The last failed this Spring just after the warranty expired.    I now just reset the trip odometer and the fuel mileage every time I fill up.    The fuel strip is almost $200, not counting the charge for dealer installation and computer calibration.   So, probably $400+ for a replacement with a full expectation that it will fail again in short order.

A guy in the Netherlands has supposedly worked up a way to use a later model float and recalibrate the computer to match, however you need to buy those parts, plus an Android phone, the app to fool the computer, and adapter cables from the phone to the bike.   I just built a resistive circuit to trick the Low Fuel warning light circuit and live with the trip odo.

Offline RBEmerson

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Re: Gas sender fail - '07 RT1200
« Reply #3 on: October 30, 2019, 09:13:19 PM »
My friend's been cut loose and now has to pay for buying another "soon to fail" strip. As you say, time to resort to tracking miles and being paranoid about the amount of gas on board. Or... "never pass gas". ;)

What's involved in at least bypassing the strip to turn off the warning?
Are you part of the solution or part of the precipitate?

Online leeo45

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Re: Gas sender fail - '07 RT1200
« Reply #4 on: October 30, 2019, 11:07:17 PM »
My friend's been cut loose and now has to pay for buying another "soon to fail" strip. As you say, time to resort to tracking miles and being paranoid about the amount of gas on board. Or... "never pass gas". ;)

What's involved in at least bypassing the strip to turn off the warning?

This has been a known problem for many years so people have come up with a couple of ways to fool the computer into thinking the tank is full.   One is cutting the wiring harness going to the fuel strip and splicing in a couple of resistors.   The other is to disconnect the cable connector from the fuel strip on top of the fuel tank and plug in a homemade circuit which the computer sees as both the strip heater and the fuel strip.   I chose the latter method simply to keep the stock harness intact.   Either method only requires simple soldering and heat shrink skills.    I'll post a quick schematic of the resistors and the connections for that second method.   

The computer basically sees R1 as the strip heater and R2 as the fuel strip resistance with a full tank.   It is likely possible to use a different resistance for R1, however that is the range others have found to be successful so that is what I used.   All of this is detailed in long threads on several different BMW boards in Europe (where they did not get the extended warranty), as well as on AdvRider.   

I probably still have extra resistors of each type somewhere in the shop.   Assuming I can find them, I'll be glad to send you or your friend one or two of each if you PM me an address.   I am not back home until the weekend so it will take a few days.  Otherwise, they are available at Frye's, Amazon, etc.

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Online leeo45

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Re: Gas sender fail - '07 RT1200
« Reply #5 on: October 30, 2019, 11:15:54 PM »
P.S.    If you install either of these computer spoofs the 'Low Fuel' light doesn't go out immediately.    It can take a few minutes for the computer to confirm resistance of the fake strip heater and then read the fuel level.    It is similar to when you fill up one of these bikes, only a bit slower to register.   After that, you have an eternally full fuel tank as far as your BMW computer knows. 

Offline RBEmerson

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Re: Gas sender fail - '07 RT1200
« Reply #6 on: October 31, 2019, 09:46:30 AM »
Thanks for the diagram - no worries about the resistors. How did you tie the resistors to the existing tank connector?
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Online leeo45

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Re: Gas sender fail - '07 RT1200
« Reply #7 on: October 31, 2019, 11:33:46 AM »
I just tinned the ends of four short pieces of thin copper wire that I used to tie the resistors together and pushed them into the plug, then taped it together.   A bit of a bodge but I didn't want to deal with finding or paying for the other side of a BMW plug.   I have seen a picture where another person just pushed the wires on the resistors into the plug.

Offline RBEmerson

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Re: Gas sender fail - '07 RT1200
« Reply #8 on: October 31, 2019, 01:42:29 PM »
Thanks! IMHO bodge may also apply to the sensor assembly. IMHO, that is. :)
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Online Andrew

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Re: Gas sender fail - '07 RT1200
« Reply #9 on: November 13, 2019, 07:48:38 PM »
There is always the BBQ starter trick  ;D

Me, I got the module from the Netherlands (Thanks DD for facilitating it) and replaced the strip with a float from a 2010. Works as the original strip did except it does not fail.

If you go to ADV there is a long thread about this .....

https://advrider.com/f/threads/fuel-strip-fix.844902/
Freedom without regulations that protect the general good is nothing less than anarchy by the rich.

"Riders might be worse than Kardashians for stupidity any more." Cornbe

Offline RBEmerson

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Re: Gas sender fail - '07 RT1200
« Reply #10 on: November 13, 2019, 08:06:30 PM »
Thanks for the link.

It's disappointing that BMW didn't have the sense to replace the strip, known to fail, with something more reliable. Sigh...
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Online Andrew

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Re: Gas sender fail - '07 RT1200
« Reply #11 on: November 14, 2019, 08:12:27 PM »
Yes disappointing, but what do you expect they are in the business of making money (they have shareholders that demand quarterly returns). THe free strip replacement was a good deal considering the original owner life cycle. The average BMW owner, I bet, keeps the bike for 5 years and by that time the new one is two generations improved so off to the new model. You see as the bikes affected with the strip are all older than 2010 (9 years) and that is a lifetime or two in the motorcycle field.
 They made a deal that kept the bike active for the max expected lifetime of the original owner, the secondary owner well "Ya bought a used bike, go and fix it." As shown the aftermarket found a way to fix it to last.
Freedom without regulations that protect the general good is nothing less than anarchy by the rich.

"Riders might be worse than Kardashians for stupidity any more." Cornbe

Offline RBEmerson

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Re: Gas sender fail - '07 RT1200
« Reply #12 on: November 14, 2019, 10:34:01 PM »
It's underwhelming to have to re-engineer part of the bike to get around a "seemed like a good idea at the time" design. At least it's not my bike.  :bigsmile:
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Online Andrew

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Re: Gas sender fail - '07 RT1200
« Reply #13 on: November 15, 2019, 08:51:44 PM »
Are you under the assumption that all bikes are engineered without possible issues or faults?   :confused:
Or do you believe the "Mother Ship" is always correct and follow what Hans and Franz tell you? Heck they most likely knew the fuel strip had a failure rate that was high but it was too late to change course (until the next upgrade of the bike) 
Remember the ford explorer that kept flipping over and in the next rendition of the vehicle ford added independent rear suspension and 2" of width yet never claiming there was an issues with the exploder (and blaming it on the firestone tires)

We know things fail and there are some really smart folks out there that want to find fixes. All of the bike owners I know want to find or have fixes for the stuff that fails on their bikes (who doesn't). When someone designs a fix (be it a minor change or a new part) I say have a close look at it, evaluate it and even buy it if it pans out to be worth. let's embrace their effort and talent, heck their work may be a better alternative to the "mother ship". And as we know the "mother ship" has a bottom line that may not be in line with our desire to have our bikes last and perform to what we expect it should.
Freedom without regulations that protect the general good is nothing less than anarchy by the rich.

"Riders might be worse than Kardashians for stupidity any more." Cornbe

Offline RBEmerson

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Re: Gas sender fail - '07 RT1200
« Reply #14 on: November 15, 2019, 10:59:33 PM »
Being unkindly blunt about it, the BMW of fame and glory (two or four wheels) is a) probably gone, and b) probably never existed.
"This BMW machine is fantastic! Lives forever!"
"Who told you that?"
"BMW!" :facepalm:
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