Regular gas?

[Carol S.]

Have had my new FFH for almost 3 weeks and am about to put gas in it. I had read somewhere that you should fill it back up when it's down to about a fourth of a tank. Has anyone else heard that you shouldn't let it get real low on gas? Also, regular gas, correct? Thanks for any info.

[Waldo]

Put gas in whenever you want. Regular is fine.

[vett93]

Does the engine gain more performance by using higher octane gas?

[hermans]

:lurk: :shift:

[acdii]

Does the engine gain more performance by using higher octane gas?

Nope, doesn't hurt though. I have run 89 since day 1, only because the station it got filled at for the first tank, and every tank ever since has 89 as their lowest grade and is only a few cents more than the 87 at the surrounding stations, cheaper when you buy $20 in groceries as they knock .20 off a gallon for 25 gallons. It may or may not help with the MPG since I have never run any other than 2 tanks of 87 when I took a trip to MN last year.

Edited April 3, 2014 by acdii

[ptjones]

Have had my new FFH for almost 3 weeks and am about to put gas in it. I had read somewhere that you should fill it back up when it's down to about a fourth of a tank. Has anyone else heard that you shouldn't let it get real low on gas? Also, regular gas, correct? Thanks for any info.

You can do any thing you want. I have run out of gas three times with my CMAX and it is a non event because the car doesn't stop but keeps going in EV mode. So depending on how much your battery is charged determines how far you can go. A safe way to go is to gas up by the time your miles to empty is 0. You can go 20-40 miles farther than that if you had too. BTW if you run out of gas you will probably be going down hill and you will almost never run out of gas going up hill. Fuel pickup is in the back of the tank. On what gas to use Reg is the most cost effective, you gain 1mpg with premium and 2mpg with Ethanol Free Gas. FFH/CMAX are rated at 13.5gal tanks, but the CMAX holds 13.9-14gals. I don't know if anyone in FFH has run out of gas to figure out how many gals it actually holds. So if you fill up and it takes 11gals you probably had 3 more gals. in tank. :shift: :)

 

Paul

[djminfll]

I always use 87 octane, because the difference between 87 and 89 here is about $0.20-0.30, not worth the extra cost. I usually wait until the low fuel light comes on, and then I fill up at the first low-priced gas I can find. The onboard computer usually tells me I have between 40 and 50 miles until empty, but I usually only put in between 11-11.5 gallons.

[ptjones]

It would be nice if someone would run dry to find out how big the tank is. Make sure to take a gas container with a couple of gals. when you get close just in case you can't EV far enough to a gas station! Also fill the tank up all the way till you can't put anymore in it. That is the only way we will know for sure what the total capacity is. :) :shift:

 

Paul

[paulbuck]

I would disaggree about filling up the tank as much as you can; it states clearly in the manual NOT to do that. Filling too much can cause gas to leak thru the breather tube, making a mess and hazard. You should fill until the auto pump stops flow, no more.

If you want to know how big the tank is, look at the owners manual.

[lolder]

Does the engine gain more performance by using higher octane gas?

No.

[ptjones]

I would disaggree about filling up the tank as much as you can; it states clearly in the manual NOT to do that. Filling too much can cause gas to leak thru the breather tube, making a mess and hazard. You should fill until the auto pump stops flow, no more.

If you want to know how big the tank is, look at the owners manual.

I have done this several times as have many others and haven't leak anything. The Owners Manual is a legal document to protect FORD. If you read your OM It does say: "3. Slowly insert the filler nozzle fully into the fuel system, and leave the nozzle fully inserted to open both doors until you are done pumping. Hold handle higher during insertion for easier access. 4. After you are done pumping fuel,slowly remove the fuel filler nozzle-allow about five to ten seconds after pumping fuel before removing the fuel filler nozzle. This allows residual fuel to drain back into the fuel tank and not spill onto the vehicle. Note: A fuel spillage concern may occur if overfilling the fuel tank. Do not overfill the tank to the point that the fuel is able to bypass the fuel filler nozzle. The overfilled fuel may run down the drain located below and in front of the fuel filler door."

As you can see it said not to spill gas on the ground, nothing about first or second click on the fuel pump. I can guaranty you if you fill up your tank from empty it will take more than 13.5gals.

BTW this forum is to help FFH owners with questions that aren't answered in the OM. :)

 

Paul

[Texasota]

It would be nice if someone would run dry to find out how big the tank is.

Do a google search on fuel pump damage resulting from running out of gas and you will find lots of discussion and opinions on this matter. Most of it describes how the fuel pump resides in the fuel tank and relies on the gasoline to lubricate and cool the fuel pump.

 

I don't know if this is trues for all cars, some cars or maybe it is only myth. But consider the risk to your car and an expensive repair by intentionally running it dry.

[murphy]

If there is any water floating on top of the fuel in the tank, probably not with all of the alcohol in today's fuel, and it gets pumped into the system because it was run dry it could damage the fuel system or the engine. Especially if it's winter and it freezes. Why take the chance for a meaningless test.

[Carol S.]

Thanks for all of the replies. I've never been one to go much below a quarter of a tank before filling up. My husband on the other hand is one who will let that light go on and then get gas...

[ptjones]

Do a google search on fuel pump damage resulting from running out of gas and you will find lots of discussion and opinions on this matter. Most of it describes how the fuel pump resides in the fuel tank and relies on the gasoline to lubricate and cool the fuel pump.

 

I don't know if this is trues for all cars, some cars or maybe it is only myth. But consider the risk to your car and an expensive repair by intentionally running it dry.

The Fuel runs through the fuel pump so this isn't a problem, as soon as there is no fuel, there's no pressure the ICE stops then fuel pump stop according to my Dealer's Service Manager

 

If there is any water floating on top of the fuel in the tank, probably not with all of the alcohol in today's fuel, and it gets pumped into the system because it was run dry it could damage the fuel system or the engine. Especially if it's winter and it freezes. Why take the chance for a meaningless test.

First, water is heavier than gas and the Ethanol will absorb water anyway so unless someone poured water in your tank you aren't going to be pumping water into the engine. I believe most people would like to know how much fuel their tank holds just in case. IMO :)

 

Paul

[Skydogz]

As a pilot I would like the manual to give real numbers, not numbers that include a fudge factor, but with cars going to idiot lights instead of real gauges; I am used to it I guess.

I have noticed when I get down to less than 40 miles to empty, my tank wil only accept 10.5 to 11 gallons of gas. So I could probably drive to ZERO miles to empty and have a 1 gallon reserve!

It would be interesting to see if the miles to empty will go to negative numbers

[ptjones]

Skydogz it won't go below 0, I have done it several times and it works out to about a gal left but "your mileage may very" LOL My tank holds 13.9-14gal depending how level the car is. I know I'm safe if the trip gauge says 12.5gal , get worried at 12.9gal , but have a high of 13.77gal so the gauge is not accurate. Unlike "normal gas cars" running out gas is a non event it just keeps on going EV, running out of HVB is a big event.LOL :)

 

Paul

[Skydogz]

Thanks Paul, this tank I am going to drive till '0 miles to go', will expect a 12 gal fillup

Stretching the envelope....

[GrySql]

I've put in 13.4 gallons without running out of gas, with the gauge on zero - not something I like to do.

Edited April 6, 2014 by GrySql

[ptjones]

Thanks Paul, this tank I am going to drive till '0 miles to go', will expect a 12 gal fillup

Stretching the envelope....

Wait a minute, don't wimp out on us now. LOL When you get close to 0 miles put a two gal gas can in the back and run her dry. With any luck you will be able to EV to a gas station, if not you got your two gals. BTW it probably will happen going down hill, you have more EV range that way. Things to do when you run out of gas, look and see how much HVB you have. Look for a gas station and if it is close EV there. If not then find a safe place to stop and put the gas can in the car. Amazingly you can actually run the HVB down to the point it can't go EV any farther and still put gas in it and the ICE will still start instantly. :) :shift:

 

Paul

[lolder]

It is NOT a good idea to run fuel injected engines out of gas. Regardless of how many times you get away with it, they are not designed to do that. The assumption that there is a gallon left after zero miles is a good one. I never go below an 1/8 th of a tank and never below 1/2 in Hurricane season. You should never go below 1/4 in Spring ( or Summer, Winter or Fall ).

[ptjones]

It is NOT a good idea to run fuel injected engines out of gas. Regardless of how many times you get away with it, they are not designed to do that. The assumption that there is a gallon left after zero miles is a good one. I never go below an 1/8 th of a tank and never below 1/2 in Hurricane season. You should never go below 1/4 in Spring ( or Summer, Winter or Fall )

 

If you would think about it you would realize a fuel pump can't pump air so there is always fuel in the fuel lines. Also the ICE does run without fuel when the battery is full while going down hill to slow the car if you use the descent button. Because there is nothing in the OM that says when to fill up it is up to the operator. I personally don't like filling anymore often than I have too and then when it's convenient and preferably a good price (I use GasBuddy) I think it makes the most sense to get gas when your getting close to zero to E. You will save time and still know you could have gone another 40miles. :) :shift:

 

Paul

Edited April 8, 2014 by ptjones

[acdii]

Do a google search on fuel pump damage resulting from running out of gas and you will find lots of discussion and opinions on this matter. Most of it describes how the fuel pump resides in the fuel tank and relies on the gasoline to lubricate and cool the fuel pump.

 

I don't know if this is trues for all cars, some cars or maybe it is only myth. But consider the risk to your car and an expensive repair by intentionally running it dry.

Been there, done that, and $2500 later had all new wiring in the trunk along with a new fuel pump. Pump seized from running dry too many times and for some reason did not blow the fuse, but melted the wiring instead. Running a tank dry as a test to see how much fuel a tank can hold is VERY bad advice. Does it really matter any way? Just fill it before or when DTE hits 0 and dont worry about it.

[Waldo]

Another risk to running out of fuel is running the engine lean and creating detonation. On my 94 RX7 turbo, the rotary engine is so sensitive that there have been reports of people who ran out of fuel while running under boost and blowing the apex seals after just one occurrence. That's why everyone who autocrossed them always ran with the tank full, despite the performance disadvantage of the extra weight. Now I don't think our FFH engines are particularly vulnerable to this condition, but if you run out of fuel in any engine while it is under high load, you risk causing damage.

Also when you overfill the tank, that extra gas isn't going in the tank. It's going into the evap canister where it will eventually have to be purged out, resulting in decreased fuel economy and rougher engine running. Plus over time it will muck up the evap system and you'll eventually get a check engine light.

 

Ford's are designed to have 1/16th of a tank left when it says 0 miles to empty. Given the 13.5 gallon tank, that means you have about 1.2 gallons left at zero miles to empty. No need for any experiments.

Edited April 7, 2014 by Waldo

[murphy]

1/16 of 13.5 is 0.84.