Hi everyone,

From what I can find out about my truck, it's supposed to have a 34 gallon tank...

Up until about 2 years ago, the most I could ever squeeze into it was around 34 gallons. Then I had to replace the fuel pumps (transfer and lift) and they told me they used a conversion kit that moved the pump into the tank.

Now, I constantly can put 38 gallons in it. In addition to that, I've run it dry one time and was able to put 40 gallons in it.

So my question is this... I don't necessarily doubt that I have a 34 gallon tank, but what is the total fuel capacity of the entire fuel system?

Could it be 40 gallons? Would a relocation of the pumps cause the fuel gauge to read differently so that when it's on E, it's really 4 gallons lower than it was reading before?

And just to confirm -- the fuel tank itself was never replaced. It is the stock 34 gallon tank. Unless the stock 34 gallon tank isn't really a 34 gallon tank.

The first time I put 38 gallons in it, I reported the gas station for having jacked up their pump meters... the State went and tested them as being accurate. I can put 38 gallons in it on a regular basis no matter what gas station I go to. When the needle actually points at the Empty marker, 38 gallons will fill it up.

Any thoughts on this?

Thank you,
-Michael

 

Has the tank got the fill vent (3/4 inch tube) moved to the top of the tank. If it has then that can account for an extra 5 gallons.

Why are you running your tank so low? You are too close to running out of fuel.

 

Hi Papaduck,

It does look like the fill vent goes into the top of the tank. It's hard to see, but I dont see the hose entering the tank on any of the sides. Would they have moved it as part of the fuel pump relocation work they did?

How would this add 5 gallons? The hose is only about 2-2.5 feet long?

As for running it low on fuel. I've only run out once :-) Generally, I allow 70 miles after the fuel light comes on. Sometimes I fill it up sooner than others... depending on if I'm hauling or not.

Thanks for your feedback,
-Michael

 

The OE vent line is located forward of the fuel tank module in the top of the tank. If it has been modified it will be placed to the rear of the module and is located at the highest part of the tank. The tanks are used for diesel and gasoline. Gasoline will expand more with increased temps than diesel and needs the air space to expand.

When you fill your tank, is the tank full when the pump clicks off or can you put more gallons in by slowly adding fuel? If you cannot add more fuel then it has been modded. When mine clicks off the tank is completly full and no more than a pint can be added.

I can drive for more than 100 miles before the distance to empty will start to drop, this is before the gauge starts to move.

For those that have the in tank pump, you should know that the pump is cooled by fuel in the tank. When the tank is continually being emptyed the pump is not getting the cooling that it needs and can lead to an early failure. When the low fuel light comes on it should be filled as soon as possible.

When my tank gets to about 1/3 full, I am looking for a station. I want enough fuel on hand for any emergency.

 

When filling up, I can usually get 2-3 more gallons in it after the pump clicks off if I fill it slowly. I'm pretty sure the vent tube is in the top of the tank, but it is hard to see.

Thanks again,
-Michael

 

I get 5-6 gallons after it clicks off, so 39-40 gallon total using the pump-click-pump-click procedure. I also average 120 miles before my needle starts to move, my DTE usually won't change until about 150 miles for some reason.