Gas Tank problem,...

[PhredzK512]

My fuel indicator registered 1/2 tank on my '87 K5,...I was cruising down the road and then it sputtered to a halt and wouldn't kick back over,...I put more gas in it then it started,...so what just happened? Is my bubble in my tank stuck? How do I get a prognosis on this one? I'm hoping I won't have to remove the whole tank.

 

[Fordum]

Sounds like what happened was you ran out of gas.........
If you can't work on it right now, you can try filling it up and see if the gauge goes to full.
Does your gauge go to empty when you turn the key off? If not, then you may have just lost power to the gauge and it stopped where ever it was.

If the float went bad, then you will either have to drop the tank, take the body off, or cut a hole in the bed to replace the unit.

 

[PhredzK512]

Thank you Fordum,...the gauge register's 1/2,..but the needle doesn't drop towards empty once the key is off, so that must indicate the gas gauge unit not having power then? I will fill it up to see if the needle goes to full and if doesn't move then I will have to find out where the problem is.

 

[Fordum]

Most GMs are of a design that the needle only moves under power. I was pretty sure yours was.
Ford, and most others will go to zero, or somewhere when power is removed. While GM's system eliminates the need for gauge voltage regulators, and Ford has adopted the same system, I have always considered it a flawed idea.

If you should lose power to the gauges, then they would stay where they were when the power was lost.
With no obvious indication that they were no longer giving real readings.

So, in your case, if you fill the tank and the gauge goes to full, then probably something has gone wrong with the sending unit in the tank.
If it does not move, then it still could be the sending unit, or the gauge may have failed or lost power.
I have driven a long time with a faulty gauge while waiting for a good time to drop a tank.
I usually know about what mileage my truck gets, and I reset the odometer every time I fill up.
I just drive until the number of miles I have driven are about the same as I would get out of 3/4 of a tank and then refill.
Doing that, will let you get by until you can determine what needs to be done.

If the tank needs to come out, I would throw in a 5 gal can, and drive until it runs out. Watching the mileage to be sure you are not likely to run out on top of a big overpass.
Then, pour in just enough to get you home. Thus the tank will be nice and empty when you go to drop it.

Just remember that an empty tank is much more dangerous than a full one when it comes to sparks.
Full tanks burn, empty tanks explode.

 

[rampage]

You can empty the tank very easily, or if you need to give your buddy on the trail some spare gas.

Disconnect the fuel line at the fuel filter. Put a piece of rubber hose over the end of the line coming from the tank and other end into a container. Then, if you unplug the wire harness for the gas tank (the connector is located on the driver's side next to the frame rail just in front of the tank) the gray wire is the power to the pump and the purple wire is for the sending unit. If you connect a 12V supply to the gray wire and ground to any metal part, the pump will operate. Your tank will be empty in minutes.


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