Fuel gauge problems

[Regaldan80]

Hi all:

 

My wife and I just took delivery of our FFH SE last week, and she reported a problem with the fuel gauge to me this morning. She filled up last night (it was at less than 1/4 full), but it only took about 9 gallons. The gauge read that it was a full tank. She got in the car this morning, and it went straight to 3/4 full. Is this user error (at the pump, or misreading the gauge), or could something be going on with the tank/gauge? The dealer gave it to us at a full tank, and this is the first time we've filled it.

[jeff_h]

Don't sweat it, that's been normal behavior for most with the first several tanks as the system builds a MPG history (for lack of a more technical term) from which to predict your fuel level and distance to empty (DTE)... mine did exactly the same thing, but after a few tanks it became pretty accurate.

[Griswald]

Filling this thing is a real exercise in patience.

 

Full flow until it clicks off, full flow until it clicks off again, trickle another 2 or so gallons into it. That should fill it up to its 13.5 gallon capacity.

 

At least that's what has worked for me in my short time as an owner.

[acdii]

Many many threads related to this. One thread has the explanation of how the fuel gauge, and DTE works. In short, the fuel gauge you see on the dash is an averaged calculation of what the car registers in the amount of fuel that is in the tank. It isn't a 1:1 of the float level like in older cars. Sounds goofy but its all some mad programming that Ford did on the Hybrids.

[Easy Rider]

Full flow until it clicks off, full flow until it clicks off again, trickle another 2 or so gallons into it. That should fill it up to its 13.5 gallon capacity.

 

Bad habit to get into. Potentially REALLY bad because that method tends to OVERfill it and might eventually damage the vapor recovery system.

 

First, the gauges are purposely very conservative.....on all cars these days; that applies to the DTE number too.

Over the last 2 years, I've had a Malibu, an Elantra, a Toyota and this Ford. ALL of the gas gauges said empty when there still was 10 to 15% left in the tank.

For a 13 gallon tank, that can be as much as TWO gallons.

On some models this is done to try and keep the owner from running it totally empty......because the fuel pump is cooled by gas in the bottom of the tank.

 

So what's the solution ?

Don't drive past E or zero on the DTE and you should be very safe.

And do NOT cram in gas past the second click.

If you fill at 1/4, it might only take 9 gallons; at E maybe 11 or so.

 

Repairs to the evap emission system can be very expensive......and the fuel pump too if you repeatedly run it dry.

Edited May 30, 2014 by Easy Rider

[Griswald]

 

Bad habit to get into. Potentially REALLY bad because that method tends to OVERfill it and might eventually damage the vapor recovery system.

 

 

 

 

Been filling gas tanks on fuel injected and vapor recovered cars since my 1985 Mustang. Never had a vapor system or fuel pump go bad. I really think thats a leftover idea, like 3000 mile oil changes and rustproofing.

 

Besides, who would design a fuel pump that would use all of the gasoline it sits in. Simply raising the inlet by 1/2" or setting the pump in a small depression would eliminate that "problem" and the gasoline pumps all have vapor recovery on them and those seem to always work and liquid gasoline is pouring out of them...

Edited May 30, 2014 by Griswald

[Easy Rider]

 

Been filling gas tanks on fuel injected and vapor recovered cars since my 1985 Mustang. Never had a vapor system or fuel pump go bad. I really think thats a leftover idea, like 3000 mile oil changes and rustproofing.

 

I'm offering you what is commonly known in the auto industry as good advice about this.

If you don't believe that, ask a few "seasoned" mechanics about it.

You may choose to ignore it if you want; no skin off my nose.

 

You have been lucky in the past with overfilling your tanks.

Some of the people that went over Niagara Falls lived to tell about it too.

 

I don't think that encouraging others to take the risk that YOU take is a responsible thing to do.

 

Cheers.

[Regaldan80]

Just wanted to update everyone on this...

 

We recently took the car on a road trip, and after filling it three more times since the last post, it continues to only take 9 gallons (give or take a tenth) of fuel. The last time I filled it, it was at about 1/8th of a tank, so it should have taken more than 9 gallons. The miles to empty calculation matches what the gauge is reading, but it still seems like the car should need more gas than what it does.

 

This will be the 4th tank now, and it still seems to be a bit off. Is this something I should take it into the dealer for?

[acdii]

Just wanted to update everyone on this...

 

We recently took the car on a road trip, and after filling it three more times since the last post, it continues to only take 9 gallons (give or take a tenth) of fuel. The last time I filled it, it was at about 1/8th of a tank, so it should have taken more than 9 gallons. The miles to empty calculation matches what the gauge is reading, but it still seems like the car should need more gas than what it does.

 

This will be the 4th tank now, and it still seems to be a bit off. Is this something I should take it into the dealer for?

Multiply the MPG your car is getting, not the dash reading, but the actual hand calculated miles driven/gallons used, multiply that by 12.5, and drive that many miles, ignoring the gauge. You should be able to put in 12.5 gallons or more at that point. Do that for a few tanks, and it will become more accurate.

 

If you run out of gas, knowing you have filled the tank fully, then take it to the dealer, as there is a problem with the tank.

 

I rarely put ore than 11 gallons in, and my gauge reflects that. It learns where your empty point is based on how much you put in at each fill.

[mwr]

It learns where your empty point is based on how much you put in at each fill.

That sounds truly weird. Do you know that it works that way?

[billford]

 

Bad habit to get into. Potentially REALLY bad because that method tends to OVERfill it and might eventually damage the vapor recovery system.

 

First, the gauges are purposely very conservative.....on all cars these days; that applies to the DTE number too.

Over the last 2 years, I've had a Malibu, an Elantra, a Toyota and this Ford. ALL of the gas gauges said empty when there still was 10 to 15% left in the tank.

For a 13 gallon tank, that can be as much as TWO gallons.

On some models this is done to try and keep the owner from running it totally empty......because the fuel pump is cooled by gas in the bottom of the tank.

 

So what's the solution ?

Don't drive past E or zero on the DTE and you should be very safe.

And do NOT cram in gas past the second click.

If you fill at 1/4, it might only take 9 gallons; at E maybe 11 or so.

 

Repairs to the evap emission system can be very expensive......and the fuel pump too if you repeatedly run it dry.

 

I agree that the evap system can be damaged.

 

I had a habit of overfilling my F150 tank to the very top. On a hot day, fuel would seep out of the vapor canister and there would be a few drops on the ground.

 

Unfortunately my bad habit has carried over to the Fusion, but it will stop today. 2 clicks at the pump is the maximum now...

[acdii]

That sounds truly weird. Do you know that it works that way?

Somewhere is a PDF explaining how the fuel system works. I will post the thread here when I find it.

 

 

Here it is http://fordfusionhybridforum.com/topic/7913-general-info-for-ffh-techies/?p=70255

 

Somewhere in the first link is the explanation of the fuel system. Basically the fuel sender unit is used to calculate an average of fuel in the tank. Somewhere else I had posted a theory on how it all works, and the discrepancy of the fuel gauge, and only being able to put in 11 gallons.

Edited June 23, 2014 by acdii

[Darkside]

I read through parts of the links provided so I will share. It says two clicks and it also says do not try and figure out gas mileage until 2000 - 3000 miles are on the vehicle.