Fuel level reading off?

[myjeep3]

I replaced the fuel pump because of a starting issue where it would take a long time before starting. Now it starts right up.

I had low fuel when i drop the tank, replaced the pump, drove around, thn the low fuel light came on. Stop at a slgas station, added 5 gallons, however the fuel level on dash claster shows that I have almost 1/2 tank..??? Issues?? I have the 19 gal tank.

 

[Jerry Bransford]

The TJ's gas gauge is notoriously inaccurate and pessimistic. As the fuel level drops the more pessimistic the gauge is.

When the tank is half-full the gauge will be showing closer to empty. When the pointer is on the E mark you typically still have 3-4 gallons left. I never fill my tank until the pointer is on or even just below the E. The Low Fuel light comes on when there's still 3-5 gallons left in the tank.

 

[Paparock1]

what year of Jeep do you have? What engine size do you have?

My 97 Jeep TJ with a 2.5L came stock with a 15 gal capacity tank. Looks and is identical to the 19 gal tank. The only difference is the vent tube in the 15 gal tank is longer so when you fill up to that point it cuts off at 15 gallons but the tank actually has 4 gallons of empty space in it. It is a simple mod to drop the tank and cut the vent tube back. which I did on mine, and now I get a full 19 gallons.
I did not change the fuel pump so when I fill up it stays on the full mark for 70 miles before it movers. So the first half of my fuel on my gauge takes time to get to half full reading. The half full and below moves quite a bit faster. I go 150 miles before i hit half tank. From half a tank level I drive 45 miles then my low fuel light comes on. I still have 5 gallons of fuel left in my tank so I know I have about a 60 mile range at that point.

Now they sell pump units for both tanks because the fuel level (float) would need to be different. They are different part numbers. I am guessing that maybe you have a 15 gallon part number pump installed? Something that some people dont realize is that when the low fuel light comes on most people still have 4 or 5 gallons of gas in the tank.

I hope this helps some. perhaps the fuel pump you bought and gauge cluster ohms are not within the same tolerance leaving you with a inaccurate gauge. for me every fill up I reset the trip odometer as I hate to run out of gas. I normally carry 2 gallons of gas in a jug.

 

[L J]

Depending on how much you drove around after the pump swap you could have had up to 9ish gallons after adding the 5 gallons. Fill the tank and track what the gauge reads against your trip meter as you empty it.

 

[myjeep3]

what year of Jeep do you have? What engine size do you have?

My 97 Jeep TJ with a 2.5L came stock with a 15 gal capacity tank. Looks and is identical to the 19 gal tank. The only difference is the vent tube in the 15 gal tank is longer so when you fill up to that point it cuts off at 15 gallons but the tank actually has 4 gallons of empty space in it. It is a simple mod to drop the tank and cut the vent tube back. which I did on mine, and now I get a full 19 gallons.
I did not change the fuel pump so when I fill up it stays on the full mark for 70 miles before it movers. So the first half of my fuel on my gauge takes time to get to half full reading. The half full and below moves quite a bit faster. I go 150 miles before i hit half tank. From half a tank level I drive 45 miles then my low fuel light comes on. I still have 5 gallons of fuel left in my tank so I know I have about a 60 mile range at that point.

Now they sell pump units for both tanks because the fuel level (float) would need to be different. They are different part numbers. I am guessing that maybe you have a 15 gallon part number pump installed? Something that some people dont realize is that when the low fuel light comes on most people still have 4 or 5 gallons of gas in the tank.

I hope this helps some. perhaps the fuel pump you bought and gauge cluster ohms are not within the same tolerance leaving you with a inaccurate gauge. for me every fill up I reset the trip odometer as I hate to run out of gas. I normally carry 2 gallons of gas in a jug.

I did mentioned that I had the 19 gal tank

 

[myjeep3]

Depending on how much you drove around after the pump swap you could have had up to 9ish gallons after adding the 5 gallons. Fill the tank and track what the gauge reads against your trip meter as you empty it.

Thats what am thinking too.

 

[Paparock1]

I did mentioned that I had the 19 gal tank

or do you?.... was my point. Just to try to help answer your question

 

[Jerry Bransford]

or do you?.... was my point. Just to try to help answer your question

Most TJs came with the 19 gallon tank. It had to have been a really stripped down very basic model to have come with the 15 gallon tank.

 

[myjeep3]

or do you?.... was my point. Just to try to help answer your question

Appreciate you, just that, that 15 gal tank/pump/mods you wrote threw me off. I have a 19 gal oem tank no mods.