Trick to filling gas?

[hahuang65]

As some of you may know, I ran out of gas on the road last week... that event was the catalyst to me finding out the gas tank should be closer to 9.5 gallons, with about 1.5 gallons un-usable.

 

I was always under the assumption the tank was around 5 gallons, so this was great news to me.

I also found out that I was filling up the gas incorrectly... just cuz the nozzle shuts off doesn't mean that it's full.

I guess the size and shape of the tank makes the gas easily shut the nozzle off.

 

My dealer told me the trick was to fill it much more slowly.

I tried this today... I filled it until the nozzle shut off, then filled it more AS SLOWLY AS THE PUMP ALLOWED.

I filled it until it overflowed, and then verified that the fuel was indeed filling up the section between the flap and the gas cap... and if I open the flap, it wasn't flowing down into the tank.

 

The math is as follows:

When I ran out of gas, I got a 2 gallon jerry can to fill it up.

Then drove about 15 miles to a gas station, and filled it up 1 more gallon (it shut the nozzle off so I stopped).

Today, the total I was able to fill it up was 1.5 gallons.

 

That seems like I'm still just totaling around 5 gallons.

What is my dumb ass missing here?

 

Somewhat related note... I have the @BruceBe fuel gauge mod... it's always designated full tank historically when it's about 1/4 tank and I fill up roughly 4 gallons.

Edited yesterday at 08:34 PM by hahuang65

[JohnCh]

If your totals and fill procedure above are accurate, and assuming your car wasn't used to smuggle anything into the country via a hidden compartment in the fuel tank, I wonder if you experienced a fuel delivery issue, that is discrete from your gauge accuracy? Either some kind of blockage in the tank or the fuel pump cutting out? Has this only happened once? 

[hahuang65]

@JohnCh only once.

 

When we were out of gas I attempted to crank the starter twice. Seemed like definitely out of gas.

 

As soon as get got the 2 gallons of fuel in via jerry can , cranked and started immediately. 

 

Definitely seemed like out of gas.

[KnifeySpoony]

Something's not adding up. Are you saying from running out of gas to filling the tank until overflowing that it took 5 gallons? Or that the tank only ever took 5 gallons on initial fill after build?

[hahuang65]

23 minutes ago, KnifeySpoony said:

from running out of gas to filling the tank until overflowing that it took 5 gallons

I'm saying this.

 

23 minutes ago, KnifeySpoony said:

the tank only ever took 5 gallons on initial fill after build

I'm possibly saying this. I only ever filled it to 5 gallons because

1) that's how big my jerry can was on initial fill

2) I thought it was 5 gallon capacity because the pump nozzle would auto-stop anytime I filled around 5 gallons. (I'm now aware of why this happens)

 

 

Currently, meter reads full, and seems absolutely topped out. I don't see how I could have made a mistake given I was literally out of fuel and kept track of how much I filled up....

 

but I'm gonna drive around until the meter reads 1/2 and then see how much I can fill up. I'm at 777 miles exactly when I topped the tank off.

Edited 3 hours ago by hahuang65

[KnifeySpoony]

So have you ever driven it from "fully full" until empty, or tested the range since a true fill up?

[DavidL]

I'll just add that I hold the gas pump nozzle upside down when I'm filling my 1990 Caterham to get a better angle... I kinda lean into it with my body weight to keep the vapor-recovery belows thing compressed to prevent auto shut-off (might just be a California thing).  It holds about 10 gallons, but most of the time I misjudge and get overflow.  The filler neck on my older car might be a differnt shape from the more modern Cats, however.

 

Cheers,  -David 

 

 

Edited 1 hour ago by DavidL

[jeffs]

 

I've never been able to use the auto-stop at the fuel pump in my r500.  The speed at which I can fill the tank varies from location to location, but its rarely full go.  Once I get to about 6gal I'll usually slow it down and listen for when its getting full (I'm usually only putting in around 7gal).  

 

I've also noticed the fuel gauge isn't overly accurate.  It takes significantly more time to go from 30L to 20L than it does from 10L to 0L.  Once I get to 10L I'm starting to look for a place to stop.  I don't think I've ever put more than 7.5 gal in.  While I also have a 36L tank, I'm not sure if its 1-2 gal of unusable space or if 0L on the gauge actually means another gal or so of fuel left (I don't plan on finding out).  

[hahuang65]

1 hour ago, KnifeySpoony said:

So have you ever driven it from "fully full" until empty, or tested the range since a true fill up?

I remember trying this with my very first fill-up, but I can't remember what the results were. But again, I think that was with only 5 gallons... as my habit was to stop filling when the pump nozzle stops. 

 

I'm gonna carry around a small jerry can, and test the range. I'm at 777 having pumped "fully" and then drove 2 miles home.

I'll check the mileage at 1/2 tank and then attempt to fill back to "full" and see what that volume is.

[CBuff]

I have the Bruce fuel mod which works well 420R. The first half of the tank lasts longer than the second half. I usually run it down to fairly solid on E and it will take 7.5-8 gallons (SV so 10.8 gals minus the roughly 1.5 unreachable). One time at the track i got distracted and buried the needle on E. It took almost 10 gals so maybe the 1.5 is overly safe but I dont try for that.  Here is NY they have taken the auto locks off the pumps so you have to hold it anyway. With some practice you can judge it but 1/4 of the time i still have spill over.