2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Getting 12.4 mpg on the highway...

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Old Oct 6, 2006 | 03:22 PM
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Getting 12.4 mpg on the highway...

Any idea what could be wrong here? I did a search, but not much came up. I filled up yesterday and drove 112 miles and I burned half a tank, which is about 12 or 13 miles per gallon. It was mostly highway with no spirited driving... any ideas?
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Old Oct 6, 2006 | 04:44 PM
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Wow, that's really bad. I was getting 12 driving 80mph in 4th with 65psi compression on a fresh rebuild...

I'm assuming this thing has to smell rich as hell? Are you staing under 3500 rpms? Is it running rough?
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Old Oct 6, 2006 | 05:07 PM
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No, it runs perfectly normal throughout the RPM range and there's no smell at all. I hope it's just my gas gauge, I don't really see another option. My only mods are mufflers and a short-ram intake...
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Old Oct 6, 2006 | 06:00 PM
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WAIT. You burned half a tank by the gauge, or you ADDED half a tank full of gas to get it filled?

The ONLY way to accurately get gas mileage on ANY car is to fill it, take the amount of miles you drove, and divide how many gallons it took to fill it.

Like, I drove 110 miles, took 8 gallons to fill it. 110/8 = 13.75 MPG.


The stock gauges on ALL cars are displayed incorrectly. On the FC, it seems the first 1/2 goes by in about 1/4 a tank, and the second 1/2 is the remaining 3/4 of a tank.
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Old Oct 6, 2006 | 06:02 PM
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Don't trust your gas gauge going to 1/2 tank to give you any accurate idea of mileage. On my TII, the gauge drops to 1/2 tank at about 60 miles around town (which DOES translate to 12-13 mpg), so on my car 112 miles at 1/2 tank indicated would be more like 24-25 mpg. Don't worry about it until you actually fill up and see what you've burned.
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Old Oct 6, 2006 | 07:21 PM
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your probably calculating wrong...


edit: ive been beat
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Old Oct 6, 2006 | 11:09 PM
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Yeah the top half of my gauge goes down really fast but the last quarter takes the same time as the top half of the gauge. Do what was posted above.
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Old Oct 7, 2006 | 09:40 AM
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agreed
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Old Oct 7, 2006 | 09:56 AM
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Originally Posted by adrock3217
WAIT. You burned half a tank by the gauge, or you ADDED half a tank full of gas to get it filled?

The ONLY way to accurately get gas mileage on ANY car is to fill it, take the amount of miles you drove, and divide how many gallons it took to fill it.
+1

The gauge markings are not accurate.
The gas gauge is not linear.
Only get accurate gasoline fill volume from topping the tank off after you have drive the indicated miles on the odometer.

Also, is that a Kouki 1989 - 1991 model you're driving like in your .sig?
It makes a difference in gas tank sizes.


-Ted
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Old Oct 7, 2006 | 11:55 AM
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Originally Posted by RETed
Also, is that a Kouki 1989 - 1991 model you're driving like in your .sig? It makes a difference in gas tank sizes.
I'm not sure what a Kouki model is, but it's a 1989.
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Old Oct 7, 2006 | 12:27 PM
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kouki = midlife upgrade car
89-90-91-(some 92) = kouki car

86-87-88 = zenki
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