Hi ALL

Lots of question. so I'll try to answer them here.

The only reason I took the FEH bone dry was by accident. I wanted to drain as much ethanol from my tank as possible and thought I could go further than 58 miles past 0 MTE. The weather was heavy rain and high winds yesterday, so my average was dropping. I've deluted this stuff before and the problem with bad mileage stayed. My guess is that the oxygen sensors continue to sense the the oxygenator (ethanol) and continue to run the FEH at a rich mixture and it burns more fuel.

The reason I didn't state how many miles it goes after 0 MTE, because it all depends on what kind of mileage each person gets with his or her FEH. As stated above, if you think you are getting 45mpg, than that number is 58 miles. The 1.28 gallons after 0 MTE is what I estimated, and I'm planning on using that figure when I travel that low. This was the first time I've went below 10 miles past the 0 MTE.

Again, the only warning that the ICE shut down was the tach. The LOW FUEL stayed on, and if I reset it, I got a 0 MTE. The computer would not let the FEH turn over till fuel could be pumped.

The biggest worry with running the electric motor IMO is hot weather with no cooling from the A/C compressor. The coolant can still circulate in the eCVT.

Now that I've taken the FEH to the bottom of the tank, I'm fairly sure the tank can hold 16.5 - 17gal. I was only able to put 14.5 gallons (top of the neck) all together with the extra from the can. If the FEH is sitting on with the right front down and the left rear higher than the right rear, I can put almost 2 1/2 more gallons in. RandyKato is right about 13.5 gallons from 0 MTE on a average fill.

GaryG

 

I normally don't let my tank get that low. I normally refuel when my tank gets to ~1/4 tank. When I drive to work, my round trip commute uses 1/4 tank. I work a 4 on/ 4 off schedule working 12 hour shifts. That said, from Spring to Fall, I can get away with driving all 4 days on 1 tank and refill when I get home on the fourth day. By doing this, I end up with a DTE of ~10 - 20 miles before refilling. During the winter, I will only drive 3 days and then refill.

Thanks,
Rich

 

haskell,
I don't know about your FEH, on my FEH, the "Low Fuel" warning comes on when I have roughly 54 miles left on my tank. As I has said in my inital post to Gary, the furthest I had taken it down from there was down to about 10 miles left.

Rich

 

I've heard what Nash has said before, that running your gas tank below 1/4 tank can cause the fuel pump to overheat. I have not heard it from the dealer nor is there anything in the manual about it.

So whats the story - does running less than a quarter tank overheat the fuel pump?

Dennis

 

I don't know if the pump will overheat or not, but there shouldn't be any issue until the tank runs dry.

 

When fuel is gone and thus there is no air conditioning to cool the batteries, will a hot battery still provide power to the traction motor?

 

It appears the A/C is not an option on the FEH, but a mandatory part of the hybrid system for keeping the HV battery cool on hot days. No one had the option to delete the A/C, and therefore if the A/C goes out after the three years or 36,000 miles, Ford has no choice but to cover it along with the other hybrid components under the 8 yrs/100,000 miles or the green states at 10yrs/150,000 mile warranty. Anyone think this is not the case?

Jim, my FEH performed great in 90 degree weather when I ran out of gas. I was running only about 30% ICE before that happen, and it was enough to keep the battery operating fine and continue to run fine after I ran out of gas. If you think I’m abusing the FEH, your wrong. If you look down ➘ at my MTE, you might see I know how to drive the FEH. If you have any better idea’s, please share.

GaryG

 

Gary, I'm not saying that you or anyone else has abused their car. I'm really trying to understand how it works. Let me ask my question again:

If the A/C is unavailable (such as from running out of fuel) and the battery is hot enough to normally call for A/C and the battery has a good charge, will it provide power to the traction motor?

I understand that regen would be precluded (I think) because charging the battery would certainly make it even hotter. But I'm not sure about whether charge can be drawn from the battery when it is hot and no A/C is available. I don't know if a Ni-Metal-Hydride battery heats up as it delivers power or not. It's of interest, because running out of fuel should not damage the battery if it doesn't heat up while powering the car, but might if it does.

 

Jim and the group:

The ideal temp for the HV battery housing is 82F and the desired range is between 77F - 100F. If the temp goes below -40F or above 135F, a trouble code (DTC) will will be flagged. Also, if any climate controls/circuitry have a failure, you will get a DTC light on the dash.

When I ran out of gas, the PCM (powertrain Control Module) and other system computers put the FEH in a LOS (limited operation strategy) to allow me to continue with the working components of the FEH. The TBCM (traction battery control module) monitor's many things including the battery temp, fans (2), vent door and A/C valve for refrig circulation and pressure. The PCM has the option of disengaging the HV battery do to overheating or any other malfuntion the TBCM is reporting.

The HV battery was taking advantange of the A/C when the ICE was running that day when I ran out of gas. Since the battery does not demand A/C operation by starting the ICE, why would that be a factor during LOS. There must be a temp that the PCM will start the ICE for A/C cooling of the battery or disengage it's use, I do not know that answer. Due to the fact that all my systems were working properly when I ran out of gas, overheating was not an issue. I drove as far on a low SoC as I have done with a full SoC in EV with no problems. It would be rare for many of you to run out of gas with a low SoC, but knowing what I do now, most people would make it to a gas station within 3 miles. You may have to use the jump start feature, but WTF. Once the ICE starts, the A/C will help keep the battery cool for recharge (not discharge) till things get back to normal. My ICE did get a run up because the battery was drawing to much power during recharge and the A/C did not have time to cool, I think.

You can bet Ford has protected the battery with giving such an extended warranty. Jim, relax and enjoy the FEH, it takes care of itself and you better than any vehicle I've ever owned.

GaryG

 

Thanks, Gary. One question/clarification:

You wrote, "Since the battery does not demand A/C operation by starting the ICE..."

I assumed it did start the ICE if it was off and the battery reached the temp at which it needs the A/C. I could imagine that happening from regen during EV mode.

Theres another thread on here where the person (with a bad A/C) feels the battery would not power the traction motor when it was hot.

This is confusing!

Thanks for the infomation.