scangauge accuracy

[mendozer]

I liked my SG when I first installed it, but I'm wondering about it's accuracy now. I noticed that my trip MPG is now averaging 16.9 mpg where it used to be more like 18-19. I also notice that my gas fillups are only going about 230-240 miles before the empty light comes on where it use to be a bit over 300. I did add bigger tired, and a bit knobbier so that would affect it a bit but 70 miles?

Also, my transmission temps don't really get up to 160 unless I'm climbing a hill and I've already been driving for 20-30 minutes. Is that supposed to be the case? I was under the impression that the tranny likes to be at 160 and of course heat kills it. But running too cool is bad for lubrication. It wouldn't make sense for Toyota to make a tranny that took that long to warm up, so I wonder if my gauge is accurate.

Anyone else notice this, or am I losing my mind?

 

[pauldub]

Why don't you just calculate the mpg after a few gas fill ups and compare that to the scangauge. I think your tranny temp is fine.

 

[mendozer]

I used to do that, think it was coming out at 17.5 recently. I'll check again. So running trannys below normal temps isn't bad? I've always wondered if it was doing harm leaving the house at 630 AM while the tranny's at 60F

 

[Mark_BC]

I wonder how mine can possibly be accurate when I go down a hill and it starts giving me a gazillion mpg and then konks out until I apply the gas again.

 

[19963.4lsr5]

Do you compare the fillup gallons to what you actually put in the tank? You can change the correction factor to get it more accurate.

My SG in my Saturn is dead nuts to .1gal off on the fillup. So I believe my mpg as being accurate.

If you do most of your driving with the torque converter in lock up your not going to put much heat into the trans fluid.


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[LittleCaesar]

SG can be finicky with gas numbers, IMHO, so I don't even calculate them anymore. For my Lexus ES 330, sure, but for the 4runner it doesn't matter to me.

As long as the ATF is red and clean, don't fret over anything. Drive and enjoy.

 

[Ruiner]

you are better off using something like the iphone app roadtrip to input miles, gallons of fuel, etc and getting a real MPG.

 

[jgue467]

...
I did add bigger tired, and a bit knobbier so that would affect it a bit but 70 miles?

Also, my transmission temps don't really get up to 160 unless I'm climbing a hill and I've already been driving for 20-30 minutes. Is that supposed to be the case? ...

Bigger tires especially with offroad lugs and a lift will definetly affect mpgs.

My tranny takes just as long to get to 160 and I live in central texas where it gets above 100 about 90 days a year. :cowboy:

 

[JayRolla]

If you still have the trans cooler in the radiator in route your trans will warm up just fine.

Watching numbers on SG tends to make people over think a lot of stuff.

 

[phattyduck]

If you bumped up your tire size, you need to account for that in the miles traveled. For example, a 5% bigger tires will make your MPG seem 5% worse than it actually is unless you account for that. That is on top of the actual decrease in MPG from larger/heavier tires.

You should be calibrating the Scangauge when you fill up anyway if you are using the MPG function, otherwise it will be nowhere near accurate enough to be useful.

-Charlie