Do others find the "Distance to Empty" number offered by the system to be extremely inaccurate? My 2023 NX 350h, usually shows that I have around 450 or more miles of range just after I fill the tank (usually with regular/87 octane). But on a recent road trip (average speed around 65-70 mph) one time I ran the tank down to a single bar on the fuel gauge, and a purported 40 miles of range till empty, and I got less than 340 miles from the tank. This is consistent with all the other experience I have had with the "Distance to Empty" number, though I usually do not run the tank quite so low. Granted, this involves mileage at highway speeds during cold weather. Using higher octane fuel may increase MPG a little bit. And I realize there is likely further capacity beyond the "Empty" level shown. And the system, when showing "Distance" available when full does not know at what speed I will be driving and at what outside temperature the engine will be operating. But still, for it to be off by over 100 miles seems a bit extreme...

 

The gauge is completely inaccurate and I'm guessing there's anywhere from 2-4 gallons left when it says it's empty.

On a recent road trip I was curious (and not with the family in tow ). I have the 450h+ and had the high voltage battery sitting at 90% (so ~30miles) and I figured I'd use that as the backup if/when I ran out of gas. I hit 0miles left and managed to go about 25 more miles at ~75 miles/hour then another 40 miles or so at 55 miles/hr (secondary highways). Based on the mpg readout on the car that comes out to a little more than 2 gallons. I still didn't run out but I was in the middle of nowhere with the next gas station about 50 miles on my route so I bailed and got gas. I only got 12.647 gallons into that supposedly 14.5 gallon tank which means there's probably another 2 left in there.

 

The “empty” indicator isn’t accurate by design in any modern auto. There’s always a gallon or two left as a reserve.

 

Same issue with me. I always reset my trip meter, and fill up when it hits around 500 mi. One time early on, I drove until the warning light came on, filled up within a few miles and added 14.3 gal (almost fumes)!

 

Well, the distance to empty on the gauge every time you fill up is based on your driving conditions from the last fill-up. The distance to empty is an estimate, so it may not be exact. I tried looking up the information in the owner’s manual, and I found the following (see screenshots below). It seems that when the car gives a “low fuel” notification, there are still 2.6 gallons of fuel left. However, the owner’s manual recommends that you always fill up the tank before the low fuel warning or at least try to. This is because the hybrid system may not be able to start if there’s less fuel.

 

Huh ?? When the yellow warning light comes on that is when you have the 2-3 gallon reserve.

YMMV,
MidCow3

 

Keep in mind that done fuel is needed inside the tank to cool the pump and for our to not be damaged. They typically alert low fuel when you still have some fuel and when when distance remaining is 0 there is some fuel left by design.

I would not call this an issue Or inaccurate.

 

Low fuel warnings have been pessimistic in every car we've owned. Always come on with extra range available.
This thread would be a bit more inflamed if the cars low fuel warning came on just as the engine was starting to sputter to a halt, right?

 

H'mm all the Lexus bragging about range is based on the full 14.5 gallon tank. It is very poor design if the fuel is required to cool the fuel pump. Sometimes actual circumstances are used to justify poor engineering design wouldn't you say.



A much better design would be:

(1) DTE would be accurate until the gas tank was bone dry.
(2) Low fuel warning light would come on when exactly 2 gallons of gas were left. At 39 mpg this would mean 78 miles. Or at 24 mpg , 48 miles.
(3) fuel pump would be designed so that fuel was not required fo cooling and the fuel pump would work even if tank were dry.

However, as with most luxury cars ( or actually most cars) you have to make it completely idiot proof. And the idiot proofing required is higher as the car price increases.

YMMV,
MidCow3

 

If I filled up my 16' Rx350 when the warning light came on, I would always fill up with close to 14.5 gal. every time. When I would calculate my MPG in the RX, it was +/- 0.15 mpg from what the computer said (very close). Why these problem issues on my much more technically engineered 22' NX350h? LOVE my NX otherwise!

 

Lawyers and Liability and less technical Lexus owners.

YMMV,
MidCow3

 

Every car typically has 2-4 gallons of reserve fuel. This is by design to prevent the fuel pump from becoming damaged. Gasoline is the fuel pumps coolant, if you run it below empty you are essentially using reserve fuel meant to protect the fuel pump. I would strongly advise against running below E. However, it is still possible.

 

Apparently you are correct, but using the fuel to cool the fuel pump as a requirement is a very, very poor engineering design

see this article to confirm what you said : https://neighborhoodtirepros.com/blo...e-my-fuel-pump

YMMV,
MidCow3

 

Correct. Key components like your car’s fuel pump and fuel filter depend on gas being in the tank to mitigate wear. Fuel pumps in modern vehicles are submerged in gasoline to keep them cool during operation.

As the gas level decreases, the pump must work harder, heating up as a result. The longer it operates at these elevated temperatures, the greater the potential for wear and failure.

Your fuel filter is also prone to damage from fuel starvation. If you do not regularly fill up, there is a greater chance that gunk and sediment in the tank will get sucked into the filter, causing a failure. If the filter fails to catch this debris, the sediment could clog fuel injectors.

Additionally, low fuel in your gas tank could be especially hazardous in months where temperatures dip below freezing. A tank that is void of fuel is a breeding ground for condensation during these chilling months.

If the condensation enters the fuel line and freezes, your vehicle will not start and the lines themselves could fail because of the expansion and contraction of the freezing water.

Also, I noticed from fueling my tank, that the tank gauge basically represents about 12 gallons of usable fuel with the 2.5 gallons in reserve not measured which represents the 14.5 gallons that the tank is supposed to hold.

I noticed this after the first couple of times fueling because my local gas station only offers points if you fill up with at least 10 gallons of fuel. So to get 10 gallons and seeing that the tank was 14.5 gallons I waited till I was down to about 30% of a tank to get the 10 gallons but observed that the car was only filling to about 8 1/2 gallons before the gas pump stopped.

So I figured the gas fuel gauge must be only representing usable fuel leaving out the reserve 2.5 gallons which seems to be verified when I wait till my tank is between 1/4 to 1/8 fuel on the gas gauge (or 70 miles of gas range as I average about 35 mph) because it is at that point I can get about 10 gallons added before the gas pump stops.

 

FYI, it's a bug, not a feature. I had it fixed, but it required a replacement of some components in the fuel tank and information cluster (causing the reset of the car mileage back to 0). In hindsight, had I known that the car mileage would reset back to 0, which brought along all kinds of other issues, I would not have done it. I would have rather lived with the inaccurate fuel gauge.