JASP615

I bought a new GX 470 in Aug and right now I only have around 5800 miles on it. What I noticed was when I filled my tank yesterday my gauge with the miles left (up with the temp, ALT, Degrees, so on) is not working. What happen is I filled the tank and now it tells me miles left was 210. Now I know this is very wrong on a full tank of gas (maybe a bit overfilled). I have already tried undoing the gas tank cap and putting it back on and restarting the truck but nothing works. It's counting down fine but it's just not correct. Does anyone know what this could be or how to fix it without a trip to the shop?

Sami

The G Man

It depends on what the average mpg reading is on the computer. take a look at your's and see what that reading is. If it is around 11 or 12 MPG, then the range may be right. I drive all city and I get about 15 mpg, after fill up, I get about 295 mile range on the computer. All the range does is multiply the avg. MPG by the amount of gas you have in the tank. The range on the GX is not too accurate, it tends to read high than real life driving just like the mpg computer. You only have 5800 miles on the GX, the mileage should get a bit better after a few more thousand miles. If you drive all city and go on many short trips, then the MPG will be less.

Hope that help

JASP615

Thanks G Man,

This is the first time that I notice this. When ever I use to fill up it would say 279 so this was a shock to see a full tank give me this low of a reading. I will see what happens then before I make an appointment to go into the shop.

Right now I'm still above the "full" mark and it's telling me 183 miles. I'm not to thrill with this mileage if this is the case. My 05 Escalade got better mileage then this. But I do love the truck.

Sami

The G Man

Sami, stroll thru the trip computer and see what your average mpg is reading.

loflin

Sami, you should disregard that reading normally.

Each manufacturer that includes that calculation, initializes it differently after a fill up. Some just put in the same number every time as defined by fuel tank size and EPA highway mileage.

The two scenarios to look at the number:

1. The fuel low light is on, you are less than 1/4 of a tank left, and you want an ESTIMATE of how long you can push it before heading to a gas station

2. You are on a long trip, with fairly constant driving environment (i.e. highway speeds), you are at less than 3/4 of a tank left, it will give you an ESTIMATE of whether you can make your destination or whether you will need to plan a fuel stop.

In both those cases, you have some actual miles driven for the computer to use to get your current average mpg for it to do a fairly good estimate.

At the point of a fill up, where the computer does an automatic new "miles to empty" reset, the computer has NO idea whether you are going to drive at highway speeds, crawl in stop n go traffic, haul a 6000 lb boat uphill, etc.

yaro1

Those are great points you suggest. Indeed when I was on a road trip, I lost track of gas, and had a close call in Pennsylvania. It was a little scary, since the guage read empty, but the range read 4 miles, and the nearest gas station via the nav system was 3.8 miles. I'm also aware that its estimate is fairly conservative, but it was reassuring to know that I could make it to the gas station. It is a handy feature, though not always 100% accurate.

JASP615

Has anyone noticed really poor MPG with the GX? I know that it still has a break in period but I'm only getting around 12 in the city and I don't beat the truck just drive normal. Highway I seem to be getting only around 14. I also noticed that the MPG has dropped since I had the TSB done. Could any of this make sense?

Sami

The G Man

Those mileage do not sound totally reasonable if you drive alot of short distance, start and stop the engine or stop and go traffic. Winter time is especially bad for mileage, since the car takes longer to warm up. I am getting about 13.5 in the city and maybe 16.5 on the highway. Do you use 87 or 91 octane?

CVsIS250

Could be a result of new calculations brought on by tougher MPG stadards in the US. Mine is between 17.5 and 18.

CV

The G Man

The new EPA standard for calculating MPG has nothing to do with lowering actual gas mileage of the car, it just changes the testing criteria for calculating the MPG you see on the window sticker to reflect a more realistic number during real world driving conditions. Like I mentioned earlier, a new car getting 12 MPG in the winter is not totally unreasonable if you drive all city and make many short trips.

SilverLady

I have about 8000 miles on my 06. Looking at the built in computer that shows average mpg, I generally run around 15-16 mpg "town" (not quite city driving, but lots of local roads, lights, waiting to turn, etc.). On a good highway with fairly constant speed of 55-70mph I can get 19-20 avg mpg.

When we have these really cold days and I go short trips I get the worst milage - I waste a lot of gas while the engine warms up.

One thing I noticed is that the avg mpg does not reset when you fill up. That and the timer, etc keeps a running total, even though the estimated range changes. You have to push the manual reset button if you want it to start calculating from scratch.

Even more fun is the altimeter that likes to tell me I am a couple hundred feet below sea level. Gurgle.

The G Man

I cant get that altimeter to work either.

JASP615

G man,

That's the other problem. It was working when we were at the cabin because we used a hand held GPS next to it and it was right on. The next time I was about 1000 ft off. This seems to be the only two things that are not working right all the time. And I do reset the mileage. Not all the time but most and this is when I saw the big differents from 285 down to 211 and I'm only getting about 12.9 driving on I95 constance speed for about an hour. Something isn't right. I will wait until I fill up again and see if anything changes. I also don't use the brake a lot while driving.

Sami

Pearlpower

iTrader: (2)

I find the system in this truck and my SC to be close to accurate (not perfect) and far superior to the gumpy logic that my 06 Fusion is cursed with which is way off. But, little every worked correctly in that car anyhow from day one so that is very low on my area of concern.

If I was so concerned about gas prices and mileage I never would have purchased a 4800lb V8 SUV. But it does seem your numbers jump around a bit more than mine.

The G Man

I think the altimeter just works off the barometric pressure reading, its not accurate at all, I gave up on it a long time ago. As far as getting 12.9 mph on the highway, that does seem kind of low. What octane of gas do you use? 87 or 91? Another possiblilty is bad gas, try using another gas station. I assume you have your tire pressure at 32-35 PSI. How does your GX roll when you let go of the gas, does it slow down quickly when you let go of the gas? If all else fails, bring it back to the dealer, you may have a bad sensor or a bad computer.

Good Luck