Prius Hard to Fill Fuel Tank

Steve Technical Support Specialist Cromwell, Connecticut Posted   Latest  
Question
Emissions
2006 Toyota Prius 1.5L (1NZ-FXE)—JTDKB20U867508010
Hard To Fill Fuel Tank

Customer had a complaint of hard to fill tank along with a EVAP leak code. We replaced the canister for the leak and decided to replace the fuel tank (bladder design) for the hard to fill as nothing else seemed to be the issue and found that the bladder tanks fail and cause this issue.

Customer has driven 1500 miles since last repair but still has hard to fill concern. Based upon some diagrams we found from a member on iATN, it appears the only way for air to get out of tank is through the Trap/Pump/Vent module. We tried to blow into the hose from the filler neck to the trap/pump and nothing would flow at all. The vent line and filter blow through fine. We assumed we must have a bad trap/pump, so we ordered a new one. After dropping tank and checking old one we can blow through it fine. We don't want to replace a part that is not needed. The only other area we can see on the diagram is the refuel check valve on the neck. 

When we removed the refuel check valve we can blow through one side and not the other. And when trying to suck through the vapor side, it's a little hard but not blocked off.

There is no real diagnostic information on how this system is supposed to work as it's far from a traditional EVAP system. Any help would be greatly appreciated.

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Matt Technician
Lawrence, Massachusetts
Matt
 

Hey Steve, Any codes? Does the pump shut off right away or does it get some in then "click"? Is it every time the customer tries to put fuel in? The capacity on these tanks are very small- I think about 12 gallons. That being said due to the bladder design I've never got more than 11ish gallons in one that was completely empty. Also the fuel gauge on these are very different and need to be…

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Pedro Mechanic
Tacoma, Washington
Pedro
 

This tanks have a type of blatter that streches . When you first replace them they got to stretch to size does the customer try to fill to full or is he only doing 1/4 tank fill ups just sometinhg i have run in the past

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Eric Owner/Technician
Grand Rapids, Michigan
Eric
 

It has been our experience that the bladder itself is the issue, it becomes difficult to expand if it has sat with little or no fuel in it for a long time. Such as a salvage yard tank. Possibly fill as completely as possible and continue to refuel frequently, keeping it full, slowly expanding bladder. In extreme instances, a new tank may be the only viable option.

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