Author Topic: Fuel strip calibration  (Read 1895 times)

mikegalbicka

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Fuel strip calibration
« on: October 29, 2020, 02:37:06 PM »
I had a known good fuel strip in my BMW 2007 R1200RT with a properly working fuel gauge. It was disconnected while I did some fuel pump/tank work and sat on the bench for two months. During that time I cycled the ignition switch on once to test the operation of a relay I installed so of course this caused a fuel strip fault. I hooked up the fuel strip and used my GS-911 to clear all faults then performed the fuel strip calibration and it succeeded but the fuel gauge did not work as expected. I ran the output tests and looked at real time values and they show the heater function isn’t working. I tested continuity on the fuel strip traces and find continuity on pins 1 and 4, the heater circuit, but not on pins 2 and 3, the fuel level resistance circuit. I ran another calibration and it succeeded but still no fuel gauge. How is this possible?

The fuel strip went bad on the bench or the calibration caused it yet the calibration still succeeds with a bad trace on the fuel level circuit. None of this makes sense to me.

mikegalbicka

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Re: Fuel strip calibration
« Reply #1 on: October 30, 2020, 06:16:14 PM »
I found the resistance figures for a good fuel strip and went back and tested mine against those figures and found the strip reads good. Seems my continuity reading on pins 2 and 3 wasn't registering but it does show the proper resistance. I flipped the plug to reverse the pins and the calibration failed so that seems to indicate the first orientation is correct. My only thought left is bypassing the fuel pump is interfering with the proper calibration perhaps because the heater isn't working correctly without the circuit passing through the pump. I will pull the pump again and hook the strip to the bottom of it and see if that helps.

Proper readings for a good fuel strip

1-4 = 35.8 ohms reported in thread below - mine reads 35.6
2-3 = 2475 ohms reported in thread below - mine reads 2790 but continuity does not register on my meter

Best explanation of fuel strip woes and fixes I have found anywhere so far. Includes how they work, how to zap them for temporary fix without replacing, how to get rid of blinking warning and set to always full without replacing. It is long but well worth the read.

https://advrider.com/f/threads/1200g...#post-18095884