Just a curious 'Range Meter' question..

Just out of curiosity .. One of the features I really like is the range meter .. As in the display that (Example) says you have '252 miles left' on the touchscreen.
This is pretty awesome as in, if I'm in the middle of nowhere .. And the next town (gas) is 150 miles away, I don't have to look at the gas gauge .. See it's 1/2 full .. Do some quick math in my head knowing my average mpg and decide if I better get gas here .. Or if I can wait till I get to the next town/gas.
Back in the old days, it used to be that when your needle hit 'E' (Or even the wrong side of 'E') the mfg's used to calibrate those to where there still might have been a gallon or two in the tank. A little bit of room for error.
So have any of you run yer tank down so far that the display says you have '10 miles' left and then knowing how much your tank holds .. And then filling it up .. See that 'Oh! I still had 1-2 gallons left!'
Just curious as having that bit of knowledge the next time I decide to head off into the middle of 'Nowhere Nevada' or such.
(P.S. ... Yes I know to almost never let it get below about a 1/4 tank as the fuel keeps the fuel pump(s) cool and I never do, but just curious as to what others have found..)

 

Meh, you have about 30 miles left once it gets to zero... ymmv

 

You can fill up at zero and still have a ways to go, think l pumped in about 19 gallons or so the last time it said that.

 

Almost everything you assumed is off the mark.

Range with a mostly full tank is wildly inaccurate.

DTE goes to zero when about 19gal of the 21.1gal is used.

The pump is a flow through design, as are most all EFI pumps since forever. The fuel is picked up on the bottom and exits the top.

The Taco pump lives in a well of fuel.

 

Ok, that's what I thought. It's actually a good thing there is a little bit of Margin For Error...

Oh, I know ... I've replaced a few fuel pumps in my time.. But they're not all created equal ..

And yes, as it should. But I have replaced a few pumps there the actual pump/motor (Dodge & a Ford) was at the top (Where the assembly fits into the tank) and draws off the bottom. It was (And maybe still is for older EFI rigs) recommended that you don't let the gas in the tank fall below a certain level, as the gas splashing around on the pump/motor kept the pump cool.

 

Know your vehicle's response to your driving habits.
Know your gas gauge's actual accuracy.
Use one of the additional odometers (I reset at every fill-up).
I don't rely only on gauges that tell me how many miles I have left.

Technology is helpful but we're slowly losing good driving skills.

 

The real margin for error is knowing what is really going on. My initial time with any vehicle is knowing the tank size and determining the range.


You really can't go thinking that Dodge is a pinnacle of design or reliability. Been there done that.

The Taco pump is at the bottom. There is an excellent document for the 3.5s that goes into these detail. I have not seen a similar one for the 2.7l.

General tank arrangement:


2.7l pump setup:

 

LOL! OK, OK ... (And I never said Dodge was the pinnacle of any/everything ... just what I've had the most experience with ..)
I know that gauges are never ever pin-point accurate, but they should be pretty close .. Otherwise, why even have them at all??
Yeah, I'm beginning to regret even asking a question here ...
Maybe I should start a Friday 'What's your favorite door latch color? Tell me why I'm wrong!' thread ..?? IDK.....

 

Somewhat accurate has been my experience. The most accurate one that I have ever had was on my first car. It would move with fuel slosh and the sender was in the back of the tank. So if I accelerated hard and the needle didn't move, it was time to fill up.



Chrome of course. I'm buying up parts from the Limiteds.

 

I've found my "range meter" to be fairly accurate for day to day driving. But if your towing or driving in conditions not favorable for your usual mileage, it calculates your range based on historical mileage data, not your current tanks mileage. Almost got caught with that mistake towing my boat north one vacation.

 

I've found it to be pretty accurate, it follows the scanguage down to 10km or so before it switches to the Fillup Now message..
I don't worry too much because I've got a mfc in the back.

 

Pshhh, everybody knows it’s oil rubbed bronze.

 

The sender seems to be calibrated at 19 gallons. Even when u fill up, the ECU reads 19.2 Then when you're empty there's still ~2 gal left.

 

In every vehicle that I have driven with DTE, 0 has never meant zero.


I have only seen one car that when the actual needle said empty, was it really empty. Thankfully, after the MiL smacked me upside the head, we coasted into a friend's driveway. Something like 20yrs later, I still catch hell about that.

 

Yeah. Agreed.

 

The taco has a low gas warning? I’ve driven down to 20 miles left and never seen a warning ever.

 

They aren't even close to accurate.
The reason? Because they take an average of previous data points instead of using the current one. Just think... you are driving down the road on a clear night in 2wd and you hit a snow squall. You are now in 4wd and headwinds yet the mte is still going to be using those 2wd data points.
It's a guide, nothing else.

 

Hahaha! I hit headwinds once on my bike just before the reserve light went on. It gets at least 45mpg when out on a trip. I knew where the next station was. That last 1.5gal lasted less than 40mi and about 1.5mi from that station that happened to be on the far side of a bridge with no pedestrian access. My first ride in a police car. These later gen Caprice have zero back seat room with the guards in place.

 

It would be interesting to see what data goes into the MTE number and how it updates after a change of driving habits (say going on an open freeway trip after you've been commuting in traffic for several tanks). I would assume it's either the last tank fuel economy or the average of a few of the last to get that fueled up MTE number, and then it goes down based on the position of the float in the tank.

I appreciate that the MPG automatically updates at each fuel up, my previous car required you to navigate through the setting with the car parked to reset the fuel economy numbers which I never did.

 

My first air-cooled VW came to me with a non-working gas gauge but with a 14mm socket attached to 3" 3/8 Socket Extension. The PO of my car told me that when I could hear it rattling around in the tank it was almost out of gas. Dude was right so that quickly became my 'audible' gas gauge in that car. A couple of years later I got bored and fished the socket and extension out of my tank with a magnet and it they now sit on my workbench. Sometimes I think about tossing it back in there; part of me misses the sound LOL!