Testing for MPG

[asti84]

Hi Guys. I've been trying to get a good approximate on my MPG (84 300DT with 255k). Could you enlighten me on what to do....Thanks.

Also, is there something wrong with my fuel gauge? I filled it up today when the needle on the dash was on the line before Empty. And I was only able to pump in 14.4 gallons. The manual says 21.1 (with approx. 2.8 of reserve) so at Empty, I should be able to pump at least 18.3 gallons. Is this correct . Thanks again.


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Proverbs 3: 5-6

It sounds like you want to know how to measure your fuel mileage, or you are trying to find out what fuel mileage to expect.

My wife had an '83 300DT that got about 27 on the highway, but I never did the in town driving. I expect it to be in the low twenties.

I hope I don't insult you by telling you how to measure your fuel mileage, but since that might be what you're asking here goes:

Top off the tank at your favorite fuel station. Top it off carefully so that you can fill it as close to that same level next time. Write down the odometer reading. Drive until the tank needs refilling and top it off to the same exact level again. Again write down the odometer reading and at the same write down the gallons including the two decimal places. Subtract the first fill up odometer reading from the second odometer reading. Now, divide that number, which is the number of miles from that tank, by the number of gallons. The result is miles per gallon FOR THAT TANKFUL. It will be different every time depending upon many conditions.

I have kept a log book on most every car I've driven in the last 35 years. At every fuel stop I write down: Date, Odometer reading, miles since last fuel stop and number of gallons. By keeping such records I can tell when my fuel mileage is dropping off indicating that the car needs attention. Although the mileage will be different every time, I have a good feel for what it averages.

Good luck,

[asti84]

Thanks Larry...and yes I was trying to get the most effecient way to get my MPG. Also I was trying to find out if my fuel gauge was faulty. Also I can never seem to get to the 18.3 tank capacity that this car has or is it 21.2? Any way thanks for your input and I will try this process. Thanks and God Bless.