Is this gas mileage normal
#1
CF Veteran
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Is this gas mileage normal
Hello! I have a 99 cherokee and I filled this up to full about 3 days ago with going back and forth to work which is about 6 miles to and back and then I took a small ride to find a jeep trail here which was about 40 miles away so currently my Jeep blew through all this gas in 60 miles from fill up. Also I noticed it Rev hangs at times as well. This was mentioned before in a different post but I never found the cause of it. From the trip it did pretty well as it was at a half a tank yesterday and this was the outcome from it today. But still 60 miles and that much gas to me is terrible.
#2
::CF Administrator::
The sending units on these things aren't the best...
What I would do, is grab a gas jug of your choosing. Fill it up with enough gas to get you to a service station. Fill your tank as well. Drive. Until you run out. Use your container to get you to the station to fill back up. Note mileage.
Verify mileage is what I'm getting at. See where a full tank takes you first. If it looks bad, then you can start chasing down what exactly the problem might be.
What I would do, is grab a gas jug of your choosing. Fill it up with enough gas to get you to a service station. Fill your tank as well. Drive. Until you run out. Use your container to get you to the station to fill back up. Note mileage.
Verify mileage is what I'm getting at. See where a full tank takes you first. If it looks bad, then you can start chasing down what exactly the problem might be.
#3
Senior Member
^^^ yep, what he said.... you have to fill it up, drive it, then fill it up again and do the math. You can't go by the gauge.....personally I think driving it until it runs out is going to the extreme, but then again my XJ can't do what's in Roninofako's signature.
#4
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Year: 2000
Model: Cherokee (XJ)
Engine: 4.0 L6
I don't see the point in running your tank all the way out. Fill it up at the pump, record your odometer, run it until the gauge shows nearly empty, then fill it up again at the same pump, and calculate your mileage from miles driven/gallons filled. Do this three times for a good average.
#5
::CF Administrator::
I don't see the point in running your tank all the way out. Fill it up at the pump, record your odometer, run it until the gauge shows nearly empty, then fill it up again at the same pump, and calculate your mileage from miles driven/gallons filled. Do this three times for a good average.
Kinda good to know how many miles your reserve will get you, as every Jeep will differ, we all know these gauges aren't dead nuts accurate. They give a decent ball park figure, but definitely not 100%. That's all.
And, you're right on the averages...yes running to empty is extreme, but you really only need to do it once for a reserve estimate, then run normally a couple more times, and average it out.
Last edited by Rogue4x4; 09-25-2017 at 03:07 PM.
#6
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Year: 2000
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Good points. I just always figure the tank holds at least what the owner's manual states, since that doesn't include the filler neck. That's always worked for me, and since I know the average MPG and consider driving conditions, I don't really need an accurate gauge as long as I track miles.
Last edited by Tbone289; 09-25-2017 at 03:34 PM.
#7
::CF Administrator::
Good points. I just always figure the tank holds at least what the owner's manual states, since that doesn't include the filler neck. That's always worked for me, and since I know the average MPG and consider driving conditions, I don't really need an accurate gauge as long as I track miles.
There is a mod out there to get a tad more in the tank, I've never done it. I don't run out of gas. I usually stop and fill once I hit a quarter tank.
But the other thing here, is he's unsure of what he's getting. Only reason I suggested what I did...baseline numbers. Get them first and work from there. If things look wonky right off the bat, then you know there's bigger issues.
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#8
CF Veteran
Thread Starter
eh its not accurate but its something lol whenever i start it back up after a bit of sitting it goes down a line than what it was before
#9
::CF Administrator::
Hot and cold, expansion and contraction.
Gets hotter? Expansion. Cooler? Contraction. There's all kinds of forces at play here. Add that to the not-so accurate readings we get from our gauges...plus the driving conditions and style, blahblahblah...this is why we average over several fill ups. If you're looking for pinpoint accurate results, outside a laboratory environment, you're never gonna get it, haha...
You can narrow it down to liveable numbers. Just gotta do the work. Not that hard, just do what you normally do, and record results, then compare.
Gets hotter? Expansion. Cooler? Contraction. There's all kinds of forces at play here. Add that to the not-so accurate readings we get from our gauges...plus the driving conditions and style, blahblahblah...this is why we average over several fill ups. If you're looking for pinpoint accurate results, outside a laboratory environment, you're never gonna get it, haha...
You can narrow it down to liveable numbers. Just gotta do the work. Not that hard, just do what you normally do, and record results, then compare.
#10
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Year: 2000
Model: Cherokee (XJ)
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Well, for instance my tank is listed as being around 20 gallons. I have done this, and when I ran completely out, I could only get 17.5 gallons back in, after putting in a gallon, then driving to a station. So, let's say 16-17. Right there is a difference of 3-4 gallons you're NOT getting, even though "factory specs" say 20.
Interesting... This would be a first for me. Every vehicle I've owned before allowed more than the factory "claim". I'll have to take your advice and run it all the way out!
I've seen the mod you mention as well.
#11
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Year: 1999
Model: Cherokee
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As others have said, the only way to know is to calculate (miles driven since full divided by gallons to bring back to full). Knowing your MPG will quickly give you an idea if the problem is gauge accuracy or mechanical issue.
Coincidentally I looked down at my dash when I stopped last night and saw that I was also at 60 miles since full.
Coincidentally I looked down at my dash when I stopped last night and saw that I was also at 60 miles since full.
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Year: 2000
Model: Cherokee (XJ)
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You still need to calculate your fuel mileage before we really know what that means. At this point, it could be that your fuel tank isn't accepting full volume, or your fuel mileage is poor.
Are you running stock size tires with stock speedometer gearing?
Are you running stock size tires with stock speedometer gearing?