Low Fuel Light comes on early now
It started happening when it was time for a new fuel filter, fuel pump, fuel pressure sensor, fuel module, and fuel module cable, (due to age and cracked LPFP cover) which cleared up a P008A CEL, but still the math ain't mathing.
Mostly city driving this tank. 17.4 gallon tank, so I should have 3.5 gallons left at 21.8 mpg for 304 miles. Should have 75 miles of range am I right? Or is range not factoring driving till the last sip? Not that I would ever run it dry. Usually let it get under 1/4 tank then fill at Costco with premium, and the light USE TO come on when the needle was just a tick above empty.
Why's it fibbing? 🤔




You should identify your vehicle - your profile shows, "Vehicle(s) I drive: Rental" ... so zero details. Also, you never stated current mileage.
We fill just before 1/4 tank, so no future stress.
You should identify your vehicle - your profile shows, "Vehicle(s) I drive: Rental" ... so zero details. Also, you never stated current mileage.
We fill just before 1/4 tank, so no future stress.
I don't know how anyone look at those photos and thinks that's right.
1) You didn't say you reset the counter when you last filled up, but I assume you did...
2) The "miles remaining" are calculated dynamically, based on some algorithm that heavily weights the calculations to the most recent driving you're doing. So if you average 25MPG driving 300 miles on the interstate to New York City and have two gallons of gas, you do NOT want the computer to suggest you can dodge pedestrians, food delivery kamikazes on e-bikes, and maniacal taxi drivers for fifty more miles.
3) I'm sure that MB (and from what I've seen, pretty much everyone else) build in a fudge factor. You don't get mad if your car tells you you have ten miles left if you figure out you really have 30 (OK, maybe you do...) but most folks DO get mad if it tells you you can drive 10 miles and you flame out in 6.
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Your needle is showing just a hair over 10%, and mid-30s miles remaining seems like a perfectly sensible point to warn the driver about low gas. I do drives where the next gas station can be 70-100 miles away.
Anyway, your description seems pretty much in line with what my car does as well.
I think the thing to do is to see how much gas it really takes to fill up your tank, and then do your calculations. Trying to discern how much fuel remains by relying on the miles remaining calculation is not going to be a good method. That figure can go up or down by nearly 50% based on the last few miles driven. Heck, according to the miles remaining, my car has gone 30-40 miles making more gasoline at times!
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Your needle is showing just a hair over 10%, and mid-30s miles remaining seems like a perfectly sensible point to warn the driver about low gas. I do drives where the next gas station can be 70-100 miles away.
Anyway, your description seems pretty much in line with what my car does as well.
I think the thing to do is to see how much gas it really takes to fill up your tank, and then do your calculations. Trying to discern how much fuel remains by relying on the miles remaining calculation is not going to be a good method. That figure can go up or down by nearly 50% based on the last few miles driven. Heck, according to the miles remaining, my car has gone 30-40 miles making more gasoline at times!
For the record wife says light came on yesterday, so I'm guessing 20 miles prior. I have an OBD scanner and I've been monitoring this occurrence of the low fuel light coming on at what bluedriver reads is 15% left in the tank, for 2 months now.
If this hadn't started a year after buying it and before any fuel system parts were replaced it wouldn't seem so damn early.
AI Google 🙄 says anywhere between 10 and 15% is normal, but it didn't used to.
She's always gotten great gas mileage. I got 26.2 mpg on a 300 mile one way trip recently, and 24.2 coming home, so 25.2 average, 99% highway.
Almost 142,000 mi. Got a bunch of parts money into it since buying 8k ago. New VVTs and timing chain tensioners. PCV valve. Plugs. I do all the work, except for what I had to have a shop program fuel system wise.




Parts manufacturing tolerances?
Parts manufacturing tolerances?
Also when I was experimenting with E85 I pumped the tank to empty once the light came on and I got 2 gallons out of it.
So if I had filled up immediately I may have used 59 litres of fuel so around 7 litres reserve or close to 2 gallons US.
Normally fill up before tank dips to 3/4
Range until empty can never be accurate because you may speed up, drive on a hill, rough road etc.






