o2 Prius gas tank belch almost got me today!
 

Almost got a gas bath today by filling my Prius slowly beyond the 2nd click of the pump. I heard about these tank vomits BUT now know them all too well. I saw the fuel all of a sudden rise in the filler neck and shut the pump off asap. I eased the nozzle out and man did the gurgling from hell start! If you fine folks hadnt mentioned this in the past I would have stood there like an idiot. The fuel bubbled and then was sucked into the tank real quick.

Can you tell this is the 2nd time I filled this car with fuel? The first time was uneventful.

It was a tad strange (sad) today when I calculated the mpg since last fill up that was up to the top last time. Maybe there are different levels of full, I know I have heard about these funky tanks.

The display said I was averaging 54.3 mpg for the last 275 miles BUT it took 7.1 gals of fuel which brings the actual mpg down to some 38ish. The gauge was 2 ticks above half tank mark.

Is the bladder tank really 'that' erratic to calculate mpg's with?

thanks

Tony

Re: o2 Prius gas tank belch almost got me today!
 

Yes and no. Yes, it is unreliable for individual fill-ups. But over the long haul, multiple tanks, it is the gold standard. Click on my signature block and you'll see what I mean.

What I recommend is use the pump numbers for long term consumption and the MFD for 'tests' and 'experiments.' Personally, I still harbor some doubts about the accuracy of the MFD and some of the fleet reports support this:

http://avt.inl.gov/pdf/hev/sae_hev_p...ation_2006.pdf

See pp. 33 of 36 "End-of-Life Phase II (J1634) Vs. Onboard Vehicle Computer MPG" chart:

Civic 1 AC off +21.7%
Civic 1 AC on +21.0%
Insight 1 AC off +11.0%
Insight 1 AC on +11.7%
Gen I Prius AC off +15.7%
Gen I Prius AC on +14.7%

The vehicle computers are reporting the higher MPG values. This is consistent with my observations, the MFD mileage is consistently optimistic.

Bob Wilson