1972 Skylark I ask because my gauge is dead. With the modern pump handles that click off and what seems like the old way the gas opening to the tank is diff how times do you let it click off when you are filling it and know if it full? Do you shovel the pump handle all the way in in just put the tip in a few inches or so? Unlike other times I just left the tip of the nozzle go in about 3 inches. Once it clicked off a few times I stopped. Based on my numbers that I have to track manually so I don't run out of gas today it looks I get 12.5 mpg 70/30 tow/hwy.
Back in the "olde daies" the pump nozzles do not have the "fuel capture" feature. There was no rubber dam or the inner pipe that captured the fuel when the tank was full. The back pressure of liquid would cause the pump handle to "stop", and the latter fuel capture made the handles click off from vapor pressure and if that "missed" by the earlier feature, and the nozzle inner pipe would briefly suck any excess fuel that otherwise would spill on the ground. In the early time, the nozzle often clicked off and about a 1/4 cup of fuel often spilled out. You only need fuel to the start of the filler neck at the tank, fueling until it is up to the nozzle, even back in the day, was wasteful at best. Get yourcar level, get a good strong flashlight and fill until it clicks, then wait 5 seconds. (fuel likes to foam), pull the nozzle and check with the flash light, then slowly add fuel and check with the light until you have the tank to the start of the filler neck. Calculate about 20 gallon tank, then calculate what you think you should get at 12 MPG, over 18 miles. Then drive that distance, and fill as before. Then subtract the amount of fuel added from 20 gallons. Post those numbers. Continue to drive. As long as you are only adding 18 gallons or less, you should never run out of gas based on those numbers, and after three cycles, you will know your true MPG. In the meantime, figure out why the gauge is not working and fix it. Search for "fuel gauge testing" and start there. It is either a ground, power, gauge or sender. The "fix" for each is not complicated.
Thanks for the info. I will do the flashlight thing for the time being. I have 1500 bucks in this car now as of today getting it road worthy. Money is out for now to chase down the gas gauge issues.
Diagnosing the fuel gauge doesn't cost anything. At least you'll know whats wrong. Could be as simple as a bad ground. Again which could cost nothing. At worst, its a bad sender which is about $50 I wrote up this thread to help someone diagnose fuel gauge issues- http://www.v8buick.com/index.php?threads/fuel-gauge-and-sender-operation-and-diagnosis.330220/
Open trunk. Look down next to latch, theres a wire going thru floor to tank, should be a plug there. Unplug it , stick a wire into it and ground it to a bolt on latch. Check gauge, key on. I believe full ground is empty. Either way you should see a change. If you do see a change, gauge and wiring to gauge are good. Which leaves tank sender , wire to sender or ground. So next up have some one watch gauge, and ground tank itself. If it changes, then ground issue.
I hate the modern gas cans. But there is a spout setup advertised on FB that I got, goes on the can just like old days, no need for a funnel since it is long enough to get to the filler opening.
