2018 computer showing empty fuel tank too early
- Thread starter dah
- Start date
deepfriedsushi
Member
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- 95 Miata, 14 CX5 Touring FWD, 18 CX9 GT FWD
Just filled up 14 gallons last night.
Range was 70ish miles, with 23.9mpg indicated.
Just like the CX5, the estimated range depends on driving style.
There is another thread where a couple CX9 drivers have run the tank dry with an indicated range of 5-12miles.
https://www.mazdas247.com/forum/showthread.php?123863217-2017-Signature-lemon
So this is quite the opposite and shows how much the range estimator can vary.
Range was 70ish miles, with 23.9mpg indicated.
Just like the CX5, the estimated range depends on driving style.
There is another thread where a couple CX9 drivers have run the tank dry with an indicated range of 5-12miles.
https://www.mazdas247.com/forum/showthread.php?123863217-2017-Signature-lemon
So this is quite the opposite and shows how much the range estimator can vary.
G
Guest2018
Using a more realistic 19.4 average or blended mpg against an 18 gallon tank:
1 gal = 19.4 mpg
3 gal = 58.2 miles (19.4 mpg x 3 gal)
The assumption is that you were down to 3 gallons prior to refueling as only 15 gallons of an 18 gallon tank was accepted.
58.2 - 15 = 43.2 (missing miles)
The question is: Where did the 43.2 miles go? Or, said another way: 43.2 miles / 19.4 mpg = 2.22 gallons. That's a 0.78 gallon differential. 0.78 gallons equals about 15.1 miles worth of driving (using the more down to earth 19.4 value).
Moral? How you use the throttle matters.
G
Guest2018
For some reason I' still have 18 stuck in my head. Thanks. Correcting for 1.5 gallons:
Using a more realistic 19.4 average or blended mpg against a 19.5 gallon tank:
1 gal = 19.4 mpg
4.5 gal = 87.3 miles (19.4 mpg x 4.5 gal)
The assumption is that you were down to 4.5 gallons prior to refueling as only 15 gallons of a 19.5 gallon tank was accepted.
87.3 - 15 = 72.3 (missing miles)
The question is: Where did the 72.3 miles go? Or, said another way: 72.3 miles / 19.4 mpg = 3.72 gallons missing (closer to actual probably).
The OP may have an issue here. Moreover, I'm starting to see an increasing number of Fuel and Range related issues with the 2018.
Thanks for reporting, OP.
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I just signed up to comment on my gas gauge experiences.
I've had my '17 Mazda 6 since Oct and noticed that the low gas light will come on when the gauge shows 1/8 tank. However, if you refill then you will only put 12 gallons (tank holds 16.5 gal). If I wait until the needle is on the E, it will take 14 gallons. Basically, the gauge reads that it has 2 gal less than it really has
I've had my '17 Mazda 6 since Oct and noticed that the low gas light will come on when the gauge shows 1/8 tank. However, if you refill then you will only put 12 gallons (tank holds 16.5 gal). If I wait until the needle is on the E, it will take 14 gallons. Basically, the gauge reads that it has 2 gal less than it really has
G
Guest2018
Seems about right. If on touch of "E" = 2.5 gals remaining, then you have a pretty good margin. "E" is just an "indicator" that the tank is nearing full depletion. If you start requiring tighter specs and more detail, then you would have to account for the width of the needle on the face of the gauge itself in conjunction with the width of each hash or mark and the width of "E" itself along with each of its horizontal elements. Its just not ever going to be that precise. At least your situation works in your favor.
2.5 on touch of "E" is plenty good. After checking, the published Mazda 6 fuel econ numbers are all over the place (a very wide band published) and that does not even include the i-ELOOP tech package. So, just using a flat 24 mpg... 2.5 on touch of needle gives you a nice 60 mile comfort zone in which you can smile your way to the gas station.
This is one of the primary reasons why I run any new vehicle I acquire bone dry (as I mentioned in another thread regarding fuel issues). It is that distance between where the needle first touches the "E" and Bone Dry (engine quits running) that tells me the real on-board fuel margin that could be trusted in an emergency (only). In your case, with moderate throttle, you appear to have a very nice emergency margin of at least 60 miles.
Enjoy it!
2.5 on touch of "E" is plenty good. After checking, the published Mazda 6 fuel econ numbers are all over the place (a very wide band published) and that does not even include the i-ELOOP tech package. So, just using a flat 24 mpg... 2.5 on touch of needle gives you a nice 60 mile comfort zone in which you can smile your way to the gas station.
This is one of the primary reasons why I run any new vehicle I acquire bone dry (as I mentioned in another thread regarding fuel issues). It is that distance between where the needle first touches the "E" and Bone Dry (engine quits running) that tells me the real on-board fuel margin that could be trusted in an emergency (only). In your case, with moderate throttle, you appear to have a very nice emergency margin of at least 60 miles.
Enjoy it!
With the digital gauge on the 6, there is no 'touch of E.' When it hits E, it's square on the center of the E line. Each tick of the needle is directly on a hash-mark and from E to 1/4 there are double the hash-marks. Official 2017 Mazda 6 Sport #'s are 26 city/35 hwy/29 combined. Right now I'm averaging 27.3. What threw me off is that with my 2012 Mazda 6, the light didn't come on until the tank hit 2 gals (which is how most manufacturers do it). Having the light come on with 4 gals left just seems silly. It'll show 'miles to empty' in the single digits with 2 gals still in the tank.
I work at a dealership and had service look at it and they said there was nothing wrong with it.
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I guess you didn't read this thread:
https://www.mazdas247.com/forum/showthread.php?123863217-2017-Signature-lemon
Consider yourself lucky.
G
Guest2018
Mazda is becoming more safety conscious in its old age.
Heck, I don't know - just get used to the new arrangement. A little more warning can't hurt. Now, if she completely shuts down at 1/4 tank - THEN - you've got a real problem to deal with it. I'll take the reserve and tell the dealer to keep the other cards in the deck while I play my hand.
On the other hand there is this thought. I recently had something like 5 miles showing on the gauge - the needle was sinking down under and approaching Australia, so to speak. Something happened - don't remember what it was now - but I subsequently began romping on the throttle and having a little fun. I saw some triple digits - no traffic - all safe. Lots of WOTs. Basic fun stuff. As I went for another WOT, suddenly the engine lugged. I was right near a gas station when this happened just by chance. I rolled off the freeway exist (very fortunate) and straight into the gas station on a well timed (lucky) green light through the intersection with the engine now begging for liquid it could burn. I shook my head not because I did not know how this happened, but because I allowed it to happen. I simply forgot - I was having so much fun.
I changed the fuel burn on the vehicle with all the WOT and runs to triple digits. That also changed the projected range. At that level of aggressiveness on the throttle, I never had 5 miles to go - not even close. Fortunately, the exist, green light and gas station were aligned like stars in the sky. You can't make this stuff up.
Moral? This engine (most engines) in particular drinks fuel like a prehistoric animal at WOT and higher RPMs. Yet, it sips fuel like a Humming Bird at low throttle and lower RPMs. This has everything to do with the way Mazda engineers designed the powertrain (engine and transmission combined). So, the vehicle does exactly what it was designed to do in this regard. When you drive it like you stole it, your fuel econ will suck eggs. That's just the way it is. In return however, Mazda engineers give you PLEASURE at higher RPMs. My Corvette was similar. The LS1 V8 would cruise forever on a single tank of fuel in 6th gear (OD) sipping fuel down low on the RPM curve and holding 65 easy. But, once I started banging off of red line in the lower gears and then holding 4th gear while squeezing every bit of energy I could get until shifting to 5th somewhere triple digits (I'm not saying), the fuel burn tanked it drank fuel like an old school Saturn Rocket.
Some engines maintain a level of civil fuel burn at higher RPM than others. But, the most enjoyable engines I've ever had did not have that civil characteristic. They were either flat out fun and drank fuel like a Sailor, or flat out civil and sipped like a prima donna at a cocktail party. They could not be both at the same time.
That reserve is probably there to protect you from yourself, or from some unexpected need to drive somewhat more spirited until you reach the pump.
CrazyBiker
Member
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- 14' Mazda6 GT Tech, 17' Kia Sorento SXL V6 AWD V6, BMW S1000R/RR
In my experience the gauge doesn’t count the reserve gallons which are about 2-3G. This has been true with all my cars. So range till empty is really a before reserve indicator. As a rule of thumb I always fill before I hit 1/3rd tank.
This is my experience as well. No car I’ve ever owned included the reserve in the distance to empty calculation. They’ve always read zero miles to empty with some reserve left in the tank.
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- Mazda CX-9 2012 Grand Touring FWD
I will typically refill my tank when the trip meter hits ~300 miles, when the range to empty says about 40 miles. Usually the car will take 14.5 - 16.5 gallons (21 gallon tank). On two occasions I have had the fuel warning light come on and it took 16.9 and 17.1 gallons. I work across the street from a Costco with a gas station and usually buy my gas there on my way to work, at 7.30 a.m. there is never a line, so waiting isn't an issue for me. I am risk averse and have no desire to run out of gas anywhere (I did that once in 1986 and we had to push the car to a gas station), so I am not particularly bothered that the fuel warning light comes on when there is four gallons left in the tank. I understand different people have different views.
