Pump stopped at 4 gallons. What's up?

I had a pump turn off where my mpg would be 65 so I drove 1.2 miles to the next station and put in 2.5 more gallons until that pump clicked off. That brought my actual mpg to 51 which was normal. I guess it does happen.

 

A common problem in Gen2 Prii. There is a bladder in the fuel tank that tends to produce back pressure during fills. Some pumps are sensitive to back pressure and shut off early. This problem tends to be more prevalent in cold weather when the bladder stiffens.

Take care not to accidentally overfill the tank as the carbon canister that controls fuel vapors can get polluted.

JeffD

 

I have run into pumps that are just finicky too, where they will stop at 1 or 2 gallons and I know I have used at least 7 gallons. It's happened in other vehicles too, some pumps are just weird.

 

I'll have this issue regularly as well.

In other threads, folks have mentioned "burping" the bladder... can somebody explain this again, or direct me to a thread that can explain it? Is it related to this issue? How does one do it? Thanks

 

I started having problems with incomplete fill when low-vapor nozzles were implemented in California stations several years ago. Did a little research and concluded that the problem was caused by pressure buildup in the tank during the fill process. The solution for me was to fill up with the pump nozzle fully inserted, but with the nozzle seal (rubber) pulled back slightly from the tank filler opening. Using this method, I haven't had any more problems.

 

Yup, I've started having this problem too. The first time it happened I can only fill up 2 gal. The next fill up was better tho, to almost full.

 

Sometimes, it's just a matter of bad timing.

Pump nozzles wear out and must routinely be replaced.

 

My Gen II constantly popped when filling. I finally discovered that if I put the pump in upside-down that it will fill all the way without a problem.

 

One advice that helped my Gen 2, Open the gas cap before doing any paying at the pump, the more time you give that tank, the less crabby it is.