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need help on how fuel tank relief valve operates 2005 R1200ST

robertsonbmw

New member
I have a 2005 R1200ST that the fuel tank is not venting. At the connector plug I'm getting 12.75v (batt) voltage checking from hot wire to neg terminal on batt but only 10.6v to neg return(gnd) wire when bike is running. I've tapped neg return wire(gnd) and run that to batt. Solenoid valve opens now but is this safe for engine computer? Beemer BOB email is robertsonbmw@gmail.com Thanks
 
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I assume you are checking the valve the connects the evaporative canister to the throttle body. Yes? If so then the valve will only be operated for short periods of time to suck vapors out of the charcoal canister and is mostly off. The tank itself is vented to the canister. Perhaps your tank-to-canister vent line is blocked.
 
I have a 2005 R1200ST that the fuel tank is not venting. At the connector plug I'm getting 12.75v (batt) voltage checking from hot wire to neg terminal on batt but only 10.6v to neg return(gnd) wire when bike is running. I've tapped neg return wire(gnd) and run that to batt. Solenoid valve opens now but is this safe for engine computer? Beemer BOB email is robertsonbmw@gmail.com Thanks

Hi Beemer BOB,

Please read: http://forums.bmwmoa.org/showthread.php?46055 - I'm adding that info to your thread title. It's rather obviously somewhat important info that might get people with something to offer to open the thread.

As far as your problem - I'm not sure what voltage the valve expects to see. The valve is only opened when the engine is fully warmed up.. so that might be a consideration. If the 10.6V with the valve connected? If not - that may just be stray voltage your meter is reading without a load across the circuit. The real test is after the bike is warmed up - what voltage do you see there with the valve connected to the circuit.
 
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