Why is gas tank not filling
Why does fuel tank reject fuel from nozzle before tank is filled?
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All modern vehicles have a dedicated system to manage fuel vapors (the EVAP system). If there’s a problem with this system, it can cause exactly the issue you’re seeing.
During refueling, incoming fuel has to displace air and fuel vapor from the tank. The pump nozzle monitors this and will shut off automatically if it senses back-pressure. If the vapor venting system isn’t working properly, vapors can’t escape the tank fast enough, pressure builds almost immediately, and the nozzle falsely detects a “full” condition and shuts off fuel flow.
This is a fairly common issue with this generation of Prius and I would recommend either a mechanic look into this issue or if you do want to DIY, definitely have someone with experience help for safety reasons. Perform the diagnostics/repairs in a well ventilated space and keep some form of fuel fire suppression readily available as you may deal with either fuel vapors or the fuel itself.
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Is it maybe your guage is not reading correctly? Maybe it is full? Does it shut off a lot during the filling?
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Tank was NOT full bc I had just driven 150 miles and wanted to fill up. Registered at just below half-tank, but nozzle kept shutting off, as IF it was full, but less than 1 gallon made it in.
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Hi @joea17864,
Hopefully it is not a venting problem with the fuel tank.
When the tank is being filled, the air in the tank should be expelled and this is done via pipes, a pressure valve and also a charcoal filter. A blockage anywhere in the vent system would prevent the air from being removed from the tank and the resultant pressure build up operates the valve which stops fuel from entering. At least I think that is how it works
Here's a video that explains it better than I can.
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