Mileage estimate not correct after filling up. Anyone else?

[tahoe81]

Anyone else seeing the mileage to empty estimate wrong after filling up? I've noticed it since day one and told the dealer who says they can't find anything wrong but that the mileage to empty shows an estimate after the fill-up based on average previous mileage (or something to that effect). I put $52 in my Tahoe the other day which gave me like 285 miles to empty according to the gauge and then I drove nearly two hours and by the time I reached my destination I had like 240 miles to empty. So it's like it's just not lowering the miles to empty estimate until after it reaches the point of what it's showing on the gauge.

 

[Chad G 1979]

It may have something to do with when you fill up that it takes a bit for the system to to the calculations to get your miles to empty reset. In my 16 canyon after filling, it shows around 350ish mils til empty, and once i get about 10-15 miles on the tank it updates the range to empty. I also reset my trip 1 every fill up as i use it to caclulate mileage, so that may tie into how it does its calculating.

 

[tahoe81]

It may have something to do with when you fill up that it takes a bit for the system to to the calculations to get your miles to empty reset. In my 16 canyon after filling, it shows around 350ish mils til empty, and once i get about 10-15 miles on the tank it updates the range to empty. I also reset my trip 1 every fill up as i use it to caclulate mileage, so that may tie into how it does its calculating.

Guess I'll mess around with it and see. Since noticing this, mine hasn't updated after 10-15 miles but could be based on the trip. I'll reset next time and see

 

[A1onpoint]

We just picked up a 23 suburban and the first 2 tanks display very inaccurate mileage estimate. If you find out why remember to report back here.

 

[tahoe81]

We just picked up a 23 suburban and the first 2 tanks display very inaccurate mileage estimate. If you find out why remember to report back here.

Will do. Not sure I’ll be able to figure this one out. I guess next time I’m due for service I can take a technician to the tank and fill it up. The first time I drove my 22 table off the lot with a full tank it was nearly 500 miles to empty if I recall correctly. Now, I fill up and it doesn’t normally get over like 360-380.

The one time a couple months ago I filled up completely and it said like 380 and then I drove nearly three hours and had like 320 after reaching my destination. It’s very clearly not working correctly but not something easily shown and duplicated to a technician.

 

[iamdub]

Anyone else seeing the mileage to empty estimate wrong after filling up? I've noticed it since day one and told the dealer who says they can't find anything wrong but that the mileage to empty shows an estimate after the fill-up based on average previous mileage (or something to that effect). I put $52 in my Tahoe the other day which gave me like 285 miles to empty according to the gauge and then I drove nearly two hours and by the time I reached my destination I had like 240 miles to empty. So it's like it's just not lowering the miles to empty estimate until after it reaches the point of what it's showing on the gauge.

Is it supposed to reset automatically after you fill up? I've never known any to do this, but I've never messed with the newer ones. Mine just keeps a lifetime running average until I reset it. Then, after a short distance, it'll calculate the range based on the average MPG.

Fill up, reset your average MPG and drive gently and see if the MTE goes into the 400s or thereabouts.

The one time a couple months ago I filled up completely and it said like 380 and then I drove nearly three hours and had like 320 after reaching my destination. It’s very clearly not working correctly but not something easily shown and duplicated to a technician.

You must've been cruising on the highway for most of this distance. Yes, the fuel level was dropping, which would've decreased your range. But, since driving at a relatively steady highway speed, the average MPG was so much better than your obviously more common city driving, so that countered the fuel level dropping to make the MTE only drop 60 miles.

 

[swathdiver]

Anyone else seeing the mileage to empty estimate wrong after filling up? I've noticed it since day one and told the dealer who says they can't find anything wrong but that the mileage to empty shows an estimate after the fill-up based on average previous mileage (or something to that effect). I put $52 in my Tahoe the other day which gave me like 285 miles to empty according to the gauge and then I drove nearly two hours and by the time I reached my destination I had like 240 miles to empty. So it's like it's just not lowering the miles to empty estimate until after it reaches the point of what it's showing on the gauge.

It's not wrong, it's just a different logic. The number you are seeing is based on the last tank of gas and or the last few miles of driving. If it's mostly city, the range will be low when you refuel. If you then hit the highway for a while, it is not likely to change the numbers upwards but rather be slow in drawing down the estimate.

I've had other GM cars that I liked the logic better but have gotten used to it now that I know how it works.

 

[Stbentoak]

I only pay attn to the DTE when I'm below 1/4 of a tank. At that point it most reflectively shows what happened in the preceding 1/4-1/2 tank and is probably the most accurate at that point. That is also the time I'm most concerned about refilling.

 

[tahoe81]

Is it supposed to reset automatically after you fill up? I've never known any to do this, but I've never messed with the newer ones. Mine just keeps a lifetime running average until I reset it. Then, after a short distance, it'll calculate the range based on the average MPG.

Fill up, reset your average MPG and drive gently and see if the MTE goes into the 400s or thereabouts.




You must've been cruising on the highway for most of this distance. Yes, the fuel level was dropping, which would've decreased your range. But, since driving at a relatively steady highway speed, the average MPG was so much better than your obviously more common city driving, so that countered the fuel level dropping to make the MTE only drop 60 miles.

I assumed so, but reading the replies makes me believe otherwise. I guess in my mind, if I'm filling up the tank completely, then based on the mileage per gallon the vehicle should be getting it should display roughly the same mileage until empty each fill up. Big given that it seems like it's all based on recent driving habits and recent MPG, I guess it makes sense that it won't reset.

And yes to your second thought. I filled up and then immediately jumped on the highway was was cruising around 80mph majority of the way. Your explanation makes sense, I guess I just expected it to automatically adjust at some point and reflect the new miles to empty estimate.

It's not wrong, it's just a different logic. The number you are seeing is based on the last tank of gas and or the last few miles of driving. If it's mostly city, the range will be low when you refuel. If you then hit the highway for a while, it is not likely to change the numbers upwards but rather be slow in drawing down the estimate.

I've had other GM cars that I liked the logic better but have gotten used to it now that I know how it works.

This logic makes sense to me, but still feels like it has to be a little off. I mean, at the end of the day it is what it is and as long as it notifies me before I run out, it's whatever. But given that a full tank in theory should get me like 480miles or so give or take (on the highway), it's hard for me to believe that based on my recent city driving, the full tank range would be lowered to around 360. I'd expect a difference based on recent city stop and go driving but ~100 miles less? Seems weird?

I only pay attn to the DTE when I'm below 1/4 of a tank. At that point it most reflectively shows what happened in the preceding 1/4-1/2 tank and is probably the most accurate at that point. That is also the time I'm most concerned about refilling.

True. As long as it's telling me when it's time to get more so I don't run out, then I'm good. lol

 

[swathdiver]

This logic makes sense to me, but still feels like it has to be a little off. I mean, at the end of the day it is what it is and as long as it notifies me before I run out, it's whatever. But given that a full tank in theory should get me like 480miles or so give or take (on the highway), it's hard for me to believe that based on my recent city driving, the full tank range would be lowered to around 360. I'd expect a difference based on recent city stop and go driving but ~100 miles less? Seems weird?

More than once mine has showed a range of say 92 miles and we hit the highway and drove 123 miles before the light came on.

When I first got my truck, I took it out on the road and made many 2-way 5-10 mile runs in 5 mph increments to determine what the truck's mpgs were at a given speed. This allowed me to calculate how much fuel it burned an hour at a given speed so I know more or less how far we can go based on the amount of fuel on board.

I also reset the trip time between refuelings. In all city driving, mine burns about 1.3-1.5 gallons an hour and about 4 gph @ 70 mph so if I jump into the truck after my wife has been driving it around town and there's 5 hours on the car since the last fuel stop, I reckon about 10 gallons has been burned and can plan my run accordingly.

GMT900s, two generations older than yours, do not calculate fuel used or mpgs displayed during a remote start event. Discovered this when I noticed a discrepancy between the fuel pumped and the fuel used. I don't know if yours does this or not.