This explanation makes sense to me. There were quite a few posts on this modification several years ago. I did not notice any clear explanation like this one. But several different people clearly reported cutting off only the vent tube, and then getting 19 gallons of gas into their former 15-gallon tanks. So it works.I believe what makes this happen is that the pressure differential in the tank is changed. When the gasoline level approaches the vent tube, the pressure is changed inside the tank, which then creates backpressure to the gasoline pump handle and shuts it off. By shortening the tube it allows more fuel in before the pressure builds and shuts the flow off. I maybe wrong, but I think this is how it works. Maybe someone more knowledgeable will pipe in.
Of all the earlier posts on this, on the Wrangler forum before this Wrangler TJ forum came into existence, and on the Jeep forum before the Wrangler forum came into existence, no one that I read reported needing any change to the dash gauge to work correctly.Does using the 19 gallon level sending unit require any changes to the dash gauge to work correctly????
Adam, my gas gauge did the same thing that you describe. I have not put mine back together yet, so I do not know if it is fixed. Possibly it is a different issue, though.Ive been having trouble with my fuel gauge showing 3/4 when i fill up. I'll also go 75+ miles after the gas light comes on. I was thinking that i possibly had a 19 gal fuel pump in my 15 gal tank. My pump went out this week and i saw it as an opportunity to fix the wacky gauge issue. After putting in a 15 gal pump in my 15 gal tank and running to the station it still only showed 3/4 full after a fill up. After seeing this thread its good to know that the tanks are the same size. Seeing this mod im thinking it may fix the gauge. It still doesnt explain why my new 15 gal pump doesnt show full with 15 gals in the tank but regardless an extra few gals in the tank would be nice. Ill try out the mod this weekend and give you all an update.
No. What you will see is when you fill up the gauge needle won't begin to move until the extra 4 gallons are used.Does using the 19 gallon level sending unit require any changes to the dash gauge to work correctly????
Adam, my gas gauge did the same thing that you describe. I have not put mine back together yet, so I do not know if it is fixed. Possibly it is a different issue, though.
But your profile says that you have a 1999 Sport 4.0. These all came with the 19-gallon tank standard. So you do not need to do any modification. The issue you describe must be due to something else.
Yes, I dropped the tank after running it low. I used a common utility knife and reached thru the fuel pump opening and carefully cut the plastic tube.KCsTJ seems to have cut the tube. But you say you dropped the tank. Did you cut it from the inside KCsTJ? If not please share!