Fuel Gauge Accuracy

TulsaSteve · 05-01-2010, 10:16 PM

I'm wondering if I have a problem... I just did a 2000+ mile trip (2007 370XL) so I had lots of opportunities to watch the fuel gauge.

The readings are consistent, but wrong. I can go 100+ miles without ever leaving full, and once when I let it run down to halfway between 1/4 tank and the red line, I ended up pumping 70 gallons into the tank.

Effectively 1/4 tank is "empty" for me. Not hard to adjust for, but annoying...

I'm using the stock gas cap.. Not locking. Anyone else see this on the Georgetowns?

NWJeeper · 05-01-2010, 10:20 PM

Same for us. They do that on purpose. They don't want you to become depressed watching the gauge fall so quickly after you have just filled the tank.

Our Jeeps are both the same too. Even my dad's '85 Winnebago is like that.

TulsaSteve · 05-01-2010, 10:29 PM

Quote:

Originally Posted by NWJeeper

Same for us. They do that on purpose. They don't want you to become depressed watching the gauge fall so quickly after you have just filled the tank.

Our Jeeps are both the same too. Even my dad's '85 Winnebago is like that.

Gee, that's... just... great.. Everything else I run (3 GM products) stay on full for awhile, but when it get's below half, they drop fast and stay pretty accurate all the way down. Guess I'm spoiled.

I guess the Ford engineers took a day off on "fluid level monitoring" day.

Oh well... Life goes on!

Thanks for the feedback!

ronhanson · 05-03-2010, 08:59 AM

Same here. I've recently installed a Scangauge to track fuel usage a little more but I haven't been able to calibrate it yet to see if it will be of use. Running the generator throws it off since it's just watching fuel consumption on the V10 but I don't expect it to have a huge impact. I filled between 1/4 and E yesterday and it took 69.5 gallons, scangauge said I had used 63.

wnytaxman · 05-03-2010, 09:05 AM

We have the same problem with our Itasca and it is on a Workhorse chassis. It doesn't leave full for quite a while and then it's a race to get to empty.

kvtaylor · 05-03-2010, 10:36 AM

We have the same thing on our Georgetown. Our gage is something else. We also go a 100 miles before it starts dropping. Glad to hear that there is some gas in the tank at a quarter full. Normally, I never let mine get that far. I start looking for stations at a half full. We don't have a locking cap either.

Hokiehall · 05-03-2010, 10:39 AM

Every vehicle I have ever owned does the same thing, Ford or GM. Once the gauge gets down to 1/2, it is really about 1/4.

TulsaSteve · 05-03-2010, 10:40 AM

Quote:

Originally Posted by wnytaxman

We have the same problem with our Itasca and it is on a Workhorse chassis. It doesn't leave full for quite a while and then it's a race to get to empty.

It's crazy that they can't get a fuel gauge to work right... It would be better if they just deleted the fuel gauge and associated parts from the chassis to save weight and cost.

I'll just run it like my motorcycles and use the trip odometer. I did ~400 miles over the last two days after a fill up and was able to get nearly 200 miles down the road before the needle left "full".

I'll likely cover up the gauge with some electrical tape so my wife and I don't get lazy.

TulsaSteve · 05-03-2010, 10:47 AM

Quote:

Originally Posted by Hokiehall

Every vehicle I have ever owned does the same thing, Ford or GM. Once the gauge gets down to 1/2, it is really about 1/4.

I've got a 2002 Tahoe, 1998 Corvette and a 2008 Saturn.. I can run all of them to "E" and never worry about running out of gas. Even the low fuel lights work great.

My Georgetown shows 1/4 full when I actually have 1/16th of a tank. 32 miles of range vs. 131 miles (@ 7 MPG). Also with 5 gallons left in a 75 gallon tank, no low fuel light.. nothing...

Not the end of the world.. Now I know to ignore the gauge. Maybe I can mount something on top of it that's useful.

MtnGuy · 05-03-2010, 11:01 AM

Quote:

Originally Posted by ronhanson

I've recently installed a Scangauge to track fuel usage a little more but I haven't been able to calibrate it yet to see if it will be of use. Running the generator throws it off since it's just watching fuel consumption on the V10 but I don't expect it to have a huge impact. I filled between 1/4 and E yesterday and it took 69.5 gallons, scangauge said I had used 63.

With the Scan Gauge, you have the option in the fill-up mode to change the gallons used. That will give you a truer picture of actual MPG under way. You might want to calculate the worst case scenario (ie, generator running) so that you won't run out of gas if you were figuring without the generator running.

cfsoistman · 05-03-2010, 11:05 AM

I'm totally different than the rest of you! I have a LOCKING GAS CAP! Otherwise the rest is the same. You can almost hear that bomb dropping sound after it gets below a 1/2 tank.
Do any of you have a speedometer issue. Mine is off by 3-4 mph on the slow side. I followed my wife home from the repair shop and had her maintain 60 mph. I had to drive at 64 to stay the same distance. My GPS has a mph reading which is pretty close. it shows about 4 mph difference as well.

TulsaSteve · 05-03-2010, 11:23 AM

Quote:

Originally Posted by cfsoistman

I'm totally different than the rest of you! I have a LOCKING GAS CAP! Otherwise the rest is the same. You can almost hear that bomb dropping sound after it gets below a 1/2 tank.
Do any of you have a speedometer issue. Mine is off by 3-4 mph on the slow side. I followed my wife home from the repair shop and had her maintain 60 mph. I had to drive at 64 to stay the same distance. My GPS has a mph reading which is pretty close. it shows about 4 mph difference as well.

I thought about the locking cap, but then decided to let them steal the gas out the existing hole (versus forcing them to create a new gas hole, which would mean that they might get gas on their hands/face, which would be my fault and I would need to pay for their medical bills)

Regarding the speedometer, I think mine is pretty accurate, but I'll check it against the GPS the next time I take her for a drive.

ronhanson · 05-03-2010, 04:09 PM

Quote:

Originally Posted by mtnguy

With the Scan Gauge, you have the option in the fill-up mode to change the gallons used. That will give you a truer picture of actual MPG under way. You might want to calculate the worst case scenario (ie, generator running) so that you won't run out of gas if you were figuring without the generator running.

I've only filled once since installing it and pressed the wrong button to change the amount filled! Doh! User error. Next time!

MtnGuy · 05-03-2010, 05:44 PM

Quote:

Originally Posted by ronhanson

I've only filled once since installing it and pressed the wrong button to change the amount filled! Doh! User error. Next time!

I can see how that could easily happen.

The 1st fill-up I did was a big adjustment up, then over the next couple of fill-ups I tweaked it, so that the Scan Gauge was not off but a couple of tenths either way. I figured the difference then was in how my truck was sitting.

cfsoistman · 05-03-2010, 08:25 PM

Quote:

Originally Posted by TulsaSteve

I thought about the locking cap, but then decided to let them steal the gas out the existing hole (versus forcing them to create a new gas hole, which would mean that they might get gas on their hands/face, which would be my fault and I would need to pay for their medical bills)

Regarding the speedometer, I think mine is pretty accurate, but I'll check it against the GPS the next time I take her for a drive.

I figured the cap would at least make it difficult to gain easy entry to the tank. At my house if they would attempt it the flood lights would come on at the shed and the side of the house. So for the $8.00 - $9.00 I spent at Auto-Zone for the cap isn't too much of an investment but may at least deter someone from trying to get free gas.

TulsaSteve · 05-03-2010, 08:37 PM

Quote:

Originally Posted by cfsoistman

I figured the cap would at least make it difficult to gain easy entry to the tank. At my house if they would attempt it the flood lights would come on at the shed and the side of the house. So for the $8.00 - $9.00 I spent at Auto-Zone for the cap isn't too much of an investment but may at least deter someone from trying to get free gas.

I would do the same if I stored at home. I've got a storage slot a few miles awhile for right now, but will be "storing" it at a nearby RV park/lake in the near future. I keep the tank fuel to keep water out, so I'm an easy target, although so far/so good.

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