General Category > General Discussion
Fuel Strips (Film type fuel sensor)
Inspector Gadget:
Good point, thanks!!
And that is of course why they are also connected to different ports on the ZFE.
So, I would need to take the floater (resistor value), build electronics to convert that to current-output (read: need a small voltage) that is within the range that the ZFE expects from the film type fuel sensor.
Assuming that the floater is resistive-wise similar to the film type sensor (logarithmic or linear)
I need to put my creative cap on.
StephanT:
indeed, something like that...
The bike models with Float vs Strip have different wiring harnesses.. as they use completely different pins on the ZFE..
best
Stephan
Inspector Gadget:
Thanks, I also noted that on schematics I have (from the Haynes manuals, both versions, thus also DOHC), even though their wiring diagrams are perhaps not completely accurate and/or not without faults.
(and the Haynes manuals are not fully complete/accurate either, but that is a different discussion)
In essence, it might be doable, it is a matter of how much efforts are involved.
Next to being very careful, not damaging the ZFE.
Haakon:
Just a question: How many bikes have this problem?
If all or many of the "fuelstrip" bikes have this problem I would think some firm would see a good business opportunity?
It can not be too dificult to make a digital conversion unit to fake the strip signals, with a float sensor installed?
There seems to be a limited number of bikes that have this problem?
As others have mentioned, can it be a fuel related?
Thinking of ethanol fuels.
Water residues in the fuel.
"Old" fuel- bikes not used very often.
... whatever
Haakon
-----------------------
New reply posted while I was typing:
Please do NOT trust any of the schematics, BMW`s or others!
I have several chematics for MY bike, and all have "faults". Wire colors and whatever.
I believe BMW did modifications to the wirings more often than we change underwear!! >:(
Inspector Gadget:
On the "social media" that I'm active on (mostly forums for 1200GS & 1200RT) the fuel-strip failure is a hot topic, next to 2010's 1200RT switches.
(the handlebar switches also fail a lot, likely due to cracks in the flexible print to which the switches are mounted)
Fuel-strips fails a lot.
So much that BMW halted warranty-replacements last year for some time.
And probably why BMW replaced the fuel-strip with the floater-type since production-year August 2010 for the R1200RT. (just a wild guess from my side).
In the Netherlands, Ethanol is not yet commonly added to the premium (95 ROZ/RON and above), so I would rule it out that Ethanol is the culprit in our cases where the fuel-strip fails. (sometimes repeatedly). But that is my take on that situation.
From what I have read and understood, 2 possible situations seems to be causing premature failure:
- The fuel-strip apparently have some electronics sealed at the top of the strip and apparently the sealing/encapsulation is not up to spec, causing fuel to reach the electronics and causing havoc.
I have not seen a fuel-strip in real life so I'm not sure about that.
- Miniature (micro)cracks develop along the measuring part of fuel-strip, causing disruption in the (complete) resistive path or incorrect (out-of-spec/calibrated) signals/values which the ZFE can no longer properly interpret.
From what I understand, due to mechanical load/vibrations.
This is, according to many on the different forums, resolved by micro-welding these cracks via the high-voltage output of a piezo lighter.
I know personally of a few people who had issues with their fuel-strip, build the outlined micro-welder out of a lighter and indeed resolved their problems that way.
I'm currently chewing on (read: contemplating) purchasing a complete fuel-unit with the floater-type sensor from a dismantling company to see if mechanical replacement is remotely possible and then consider what would be involved of converting the resistive output (= floater) to current-output (= fuel-strip). In very simple black-and-white it would require some voltage.
According to Ohm's Law:
U (voltage) = I (current) times R (resistance).
Current is what the ZFE expects/measures from the fuel-strip, resistance is what the floater-type will provide, so it would then be voltage to make that happen.
Mind you, from what I have read & understood from how the ZFE works with the fuel-strip, the voltage from the ZFE is modulated (PWM) and thus also the heating, and it lets to be seen if the measurements via the fuel-strip is something linear or logarithmic or something else/combination to what the ZFE interprets as the various fuel-levels.
So, it would also be the algorithm that needs to be found out when the ZFE is the fuel-strip version.
Somebody else already played with that on one of the US forums, and came up with this;
http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=770085&page=6
As for trusting schematics, wiring diagrams and so on;
I agree 100%!
I have the official BMW RepROM's and even those contain mistakes and omissions. Yikes!
Thanks for reminding me, it just turned Friday overhere, time to change my underwear again. (Joke!)
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