Low-fuel light: how many gallons?

mysleeper6

Member
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2006 Mazdaspeed6
So I'm cruising along in my MS6, headed for a destination about 40 miles from my home when I realize that a) I'm low on fuel and b) I left my wallet at home. I wasn't quite at my final destination, but I couldn't just turn around either; I had to be there at a certain time. So, I pressed on. About four miles from the end the low fuel light came on.

My previous car's owner's manual (a Ford product) clearly stated that when the low fuel light came on, 2.2 gal remained in the tank. Doing some quick math, I figured I would not have to embarass myself by asking for gas money from anyone if this car was similar, but I wanted confirmation. The manual for the MS6 states that they recommend keeping the level above 1/4 full and that when the low fuel light illuminates to fill the tank as soon as possible. It does not, however, mention a specific volume of fuel associated with the low fuel light. A quick call to Mazda roadside assistance provided no help.

Well, I completed my business and decided that I would take a chance (if you want to tell me I risked burning up my fuel pump, save it---I know) and at the same time do some computation. Long story short, I drove a total of 46 miles from the time the light illuminated, and it required 15.25 gallons to fill it up. In theory, I still had .65 gallons in the tank (15.9 gallon capacity). In total I drove 371 miles on those 15.25 gallons, or 24.3 mpg. So those 46 miles required 1.89 gallons. Adding back the .65 yields a total volume of remaining fuel when the low fuel light illuminates of approximately 2.54 gallons, so lets say 2.5 gallons and a range of 60.75 miles.

So, I know I'm stupid for leaving the wallet at home, and this may call to mind a Seinfeld episode for more than one of you, but I turned it into a learning experience. I do not recommend further research into this subject.(silly)
 
Wow. That is ironic. My adventure actually took place on Sunday, May 4, but I didn't have time to write about it until now. And, I hope you will note, my calculations actually do provide a bit of helpful info, unlike the site mentioned in the link.

i didn't understand s*** when i first read your post lol

im bad at math lol sorry


(help)
 
i've always assumed 2 gallons left when the light comes on.
 
i've done 430 miles on one tank.

i have a M6 '06

i was also was driving at 60-65 mph

speed makes all the difference.
 
On one occasion I drove just over 50 miles after the low fuel light came on. I was far from civilization and really wanted to make it to my destination. I figured I could, but after about 20-30 miles I started to get very nervous but there was simply no gas statins for the remainder of the trip. Unfortunately I did not take note of how many gallons I put into the car when I finally did get gas.

Generally speaking I get 24-25 mpg on the highway. My best tank ever was 28 mpg on an all highway trip which resulted in over 400 miles for the tank although I cannot remember the exact figure. In normal 50/50 mixed driving I seem to get 21 mpg no matter how I drive.
 
For what it's worth, my next tank I only got about 21 mpg. The driving conditions were completely different from last tank (lots of city driving). Also these were the first two tanks since I disconnected the battery to install the CAI; I think the ECU is still adapting to my driving habits. I would hesitate to push beyond 40 miles with the light on again, in spite of my calculations.

Also, as I alluded to above, I have been told you risk damaging your fuel pump (depending on who you listen to, its either an overheating issue, or a sediment issue) when habitually running the tank dry-ish.
 
Thanks for doing the math! Now I know what's left in the tank when the light appears.
 
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