Thank you I’ll write down mileage before I drive somewhere. I’ll just figure 10 mpg for easy figuring.
thank you
Larry

 

yep, when you've gone 235 miles your guage should read half if your estimated mileage is good. With roughly 145 miles left in the tank. Let us know how you do.

Remember that the float arm swings an arc. An inch of tank use when full is less swing angle then when nearing empty when the last inch of fuel will swing the arm more and move the needle the most.

 

I’ll post again as I near empty. With gas prices the way they are it may take me some time to burn 38 gallons of fuel. Thank u for all your help
Larry

 

With 38 gallons you're built to roll....top off that tank regularly. Use ethanol free if you can.

 

If your mileage guess is too conservative, you will notice you will need to put less and less in the tank. So when that happens you can increase the miles before you fill, till you get to about 30 gallons used. I would consider that empty, I would not run it too close. If you driving is the same routine and route all the time, you will find this to be very accurate, way more accurate than the gauge.

 

Thank you…that’s a great idea and I agree 30 gallons used is enough for that gas guzzler 😳😂🍻

 

If your pick up has an open bed you could carry a full gas can in it.
1 gal might not be enough and 5 gal someone may like more then you so 2 gal might be just right?
Then again you dont have to have it with you all the time only load it when you get down close to empty just in case your numbers are off.

I installed 2 new senders when rebuilding my truck and to check them I first turned on the key and seen where the needles where with no fuel in the tanks.
It was below the empty line.
I then put 5 gallons in each tank and checked again. Needles came up to the empty line so I know I have 5 gallons in each tank with the needle on the line.
When full the needles are above the full line but I dont care as long as it reads good when low.

I also check this each time I fill up as I run 1 tank down to the line and the other close.
1 tank will take 10 / 11 gallons, 16 gallon tank, and the other 14 to 15 gallons on a 19 gallon tank.
Dave ----

 

If you're the least bit worried about running out of gas, do 150 miles of your typical driving and top off again so you know your MPG. I know you want to test your sender, especially at or near E too. When the guage gets to half full as you reported that should be 23.5 gallons used. That will give you an idea of your mpg though not exact, but with enough confidence to take it down to 8 gallons left.

 

Where did your green with red stripe sending wire connect into the cluster? Does that connect to the orange fuel wire in the cluster somewhere?

 

What are you working on? There is no green/redstripe wire in the sending unit circuit on these trucks, any year, any model.

 

1979 F150 2wd 351M rear gas tank only. Wiring diagram shows either a green with red stripe wire or a blue wire from the sending unit depending on what tank you have. Is that incorrect? My gas gauge doesn't work. I have replaced the sending unit, the gauge and the ICVR. Ground out the wire, no reation at the gauge? No flashing light at the wire to the sending unit? Maybe a bad wire?

 

That is correct for a 1979 according to this diagram. https://www.fordification.net/tech/i...aster_3of9.jpg

But this forum goes from 1980 thru 1986. That's where the confusion is coming from. That being said, looking at the diagram the fuel gauge would work the same,, but the wiring colors are different for the earlier years.

 

So I was on the wrong years forum but was correct for the colors for the 79. So it is correct that year and model as I stated.