Why Topping Off won't kill your truck

[The Real Maverick]

A couple of notes
- don't attribute to Ford's engineers what is probably pushed by Ford's lawyers.
- Define "overfill". Where is the line beyond which fuel shall not sit?
- How close to "full" is a tank when the pump shuts off. Some nozzles are more sensitive than others. Are those things even calibrated?
- Faster pumping does tend to shut off a little earlier due to splashing and bubbling of the fuel in the filler neck during the filling process. This was highly evident in my old Dodge truck, where I had to fill at a slow speed or risk premature shutoff (very premature, like less than 1/2 a tank).
- Most of the cautionary notes in the manual are Ford's CYA notes, with tidbits of actual important stuff squeezed in here and there. Just like with all products these days.
- Don't equate a credential, such as an engineering license or degree, with a superior level of knowledge. While most engineers are very smart and good at what they do, the credentialization process occasionally gives the certification to someone that is not really that good at what they do (and yes, I've seen it in my profession from time to time).

Yes.

I was going to say the statements people cut & paste from the "manual" probably came from the EPA worried about spills. And that's fine. I don't want spills either. But refrained since I have no documentation of that.

I also refrained from stating there are a few different makes and models of pumps, and different states of disrepair. Which is why logic trumps a sentence in a manual.

But I posted documentation of why 2 or 3 clicks is harmless (if you don't spill while doing it.)

Nothing wrong with stopping at the first click. Continue to do so if you like.

It took a while but logical minded people have found this thread.

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[Bruce W]

Owners manual for hybrid:

EcoBeast:

https://www.fordservicecontent.com/...A&div=f&vFilteringEnabled=False&buildtype=web

[/QUOTE.

Owners manual for hybrid:

EcoBeast:

https://www.fordservicecontent.com/...A&div=f&vFilteringEnabled=False&buildtype=web

can’t be any clearer than that. Yellow triangle bad….

 

[Grabber Rick]

What will be hurt by overfilling. Looking at the OP's diagram it is number 8: fuel tank pressure control [Valve] during operation. They are generally not designed for liquids and will not last long if they see liquids often.

On previous cars I thought the same as the OP that it wont harm anything to overfill. I thought the first one replaced under warranty was a fluke but the second one that I paid $400 to the dealer to replace got my attention.

I may be a slow to change my ways but eventually I get there. I now stop at the first click.

I can say with my 07 Ford Focus I was squeezing in as much gas as possible. Then My gas gauge would go to empty and low fuel light would come on. Gauge would stay empty for about 40-50 miles then work. One time it stayed empty way longer. Since I stopped overfilling my gauge has worked every time now. I also had occasional code about first bank catalyist error. Not sure if overfilling was the issue. CEL would be on for awhile then off then on. Right now it's off.

 

[Tim d]

Why "topping off" is OK as long as you don't spill and pollute.

(And why your car care nut and Uncle Joey have unfounded worries about the "carbon filter canister".)

I put "topping off" in quotes because it's really not possible to, even if you wanted to. So everyone can relax a bit if they want.

This thread is not meant to be a debate and I'm not telling anyone what they should or should not do.

This is information. Information that shows the risks of the past likely no longer exist today.

That said, in the hybrid with capless filler tube, I find it fills fully, reliably, repeatedly with just three clicks. No need to go beyond that.

Here is the fuel system diagram from Ford.

1: fuel fill tube
2: fuel module
3: fuel level sensor
4: fuel tank
5: fuel vapor return line
(5 is what people worry about needlessly)
6: fuel pressure sensor
7: refueling vent valve that opens when you push the refuel open door button
8: fuel tank pressure control during operation
9: carbon canister
10: vent valve
11: vent to atmosphere
12: vent to engine
13: recirculation valve
14: engine intake manifold

The particular technique different individuals use to refuel their trucks should have no effect on the much worried about "carbon canister".

Hope that helps some of you sleep peacefully. How that canister got ruined in a 1998 vehicle bears no resemblance to the hybrid Maverick of today

I didn't even realize this was a thing.ive been topping off sometimes 4-5 times after the initial click for the past 50 years I have been driving cars.never had an issue.

 

[AutobahnSHO]

I didn't even realize this was a thing.ive been topping off sometimes 4-5 times after the initial click for the past 50 years I have been driving cars.never had an issue.

Cars are built differently now than even a couple decades ago.

I found it funny the owner manual for a Ford Taurus in the 1980s said "do not press the accelerator pedal while starting"- because that was common with carb'd vehicles before that. Fuel injection and computers have made that unecessary...

 

[Tim d]

Cars are built differently now than even a couple decades ago.

I found it funny the owner manual for a Ford Taurus in the 1980s said "do not press the accelerator pedal while starting"- because that was common with carb'd vehicles before that. Fuel injection and computers have made that unecessary...

True.other than my 23 mav,2 of my vehicles are 15 years old, and the 4th one is 52 years old.

 

[Mav4fun]

The system diagram is certainly helpful information but it doesn't show the actual physical dimensions/locations relative to each component. The fill neck (1) and the top of the fuel vapor return line (5) is certainly the highest point in the whole system. In the extreme, if you filled gas to the top of the fuel neck (and thus vapor vent line (5)) it would seem that fuel could reach the canister since it is lower and the vent valve (7) is opened during refueling.

 

[710-oil-614]

Ford says don't do it.

There is really no reason to do it.

I won't be doing it.

 

[Mark S.]

It took a while but logical minded people have found this thread.

You might get a better reception if you didn't continuously insult those who disagree with you.

The diagram and text you posted in support of your position addresses concerns of refueling. Given the system design, it's unlikely you will force fuel into the charcoal canister during refueling by filling your tank all the way to the filler port. What about later?

If you live in an area with large daily swings in temperature and you completely fill your tank in the morning, what happens when the fuel expands later in the day when gets hot? The system is designed to collect vapor that forms as the fuel heats up in the tank, thus preventing their release to the atmosphere. What happens if the fuel (liquid, not vapor) expands enough in the tank to fill up the vent system?

 

[srfdude44]

In addition to those folks who think its best not to overfill, INMHO there really is no reason to do so. Trying to get a mileage result from one tank refuelling is just mental masturbation. Of course this is just an opinion, so take it for what its worth. But on the other hand being consistent with filling one time is not opinion, its virtually impossible. So as someone already said, why take the chance?

 

[PanchoBarrancas]

I do the same thing. Fill till it clicks, wait 30 seconds, and do a top-off. Sometimes I can get the range over 400 miles doing that. The highest was 415. On average it's 385.

To be fair the range estimate is affected more by your mpg. Mine shows ranges from as low as 410km when I've driven several days in a row in gridlock traffic to as high as 650km when I've done mostly highway driving, both showing 100% fuel on the gauge and the app.

 

[AutobahnSHO]

Yeah, the couple extra miles driven before next fillup isn't worth the risk as well as my time spent there holding the gas pump handle...

 

[The Real Maverick]

You might get a better reception if you didn't continuously insult those who disagree with you.

The diagram and text you posted in support of your position addresses concerns of refueling. Given the system design, it's unlikely you will force fuel into the charcoal canister during refueling by filling your tank all the way to the filler port. What about later?

If you live in an area with large daily swings in temperature and you completely fill your tank in the morning, what happens when the fuel expands later in the day when gets hot? The system is designed to collect vapor that forms as the fuel heats up in the tank, thus preventing their release to the atmosphere. What happens if the fuel (liquid, not vapor) expands enough in the tank to fill up the vent system?

I can answer your questions with certainty.

Gasoline expands 0.069% per degree F.

Or 1% per 15 degrees F if you prefer.

Rounding the tank size to 15 gallons, one needs to burn 0.15 gallons on the first drive cycle to make room for 15 degrees of temperarure rise, or 0.30 gallons for a 30 degree rise to be 100% safe.

I will add though, due to physical size and shape, even after 3 clicks, or 5, your tank will not be 100% full. You really can't get them 100% full. By design. Thank your EPA for that.

 

[Glen Baker LLC]

I fill my tank till I see this.

I'm trying for that coveted 1000 Mile trophy.
That's how I roll.

Checkout high mileage per tank full threads. You'll better understand this thread and why filling it to the brim is so important.
https://www.mavericktruckclub.com/f...n-a-tank-mte-while-hauling-1300-pounds.48324/

https://www.mavericktruckclub.com/forum/threads/840-miles-•-1-tank-fuel-•-hybrid-maverick.47332/

 

[The Real Maverick]

I fill my tank till I see this.
I'm trying for that coveted 1000 Mile per tank full trophy.

That's how I roll.

That's what the yellow triangles are for in that book likely found in your glove box.

Did AI draw that?

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