Fuel Gauge wierdness

[Willard]

So I was out of gas today and went to put some in. I have been running on empty a couple of days, so I was cutting it kind of close. I put $15 in, about 5.5 gallons, and started on my way.

That's where something strange happened. I started the truck, fuel gauge went from empty to as full as possible (well past the full mark) and over the time I drove back home it slowly settled back down to around 1/4 tank, which seems like where it should be.

What could have happened here? I know there is some sort of module or something to keep the gas gauge from moving too fast, so I'm wondering if that did something weird. It's been raining so maybe I had a one-time short at the fuel level sensor and it just took that long to come back down? I just want to make sure something isn't going out on me. The fuel sender and pump has been replaced less than a year ago.

 

[Anime]

Since you say the pump assembly was replaced not long ago, my guess would be that's it, and the sender or electronics/wiring on it are going. Did you replace it with an OE pump, or something inexpensive? Depending on where you bought it, it might be worth your while to dig up the receipt. Sometimes you'll get at least a one year warranty on such things, and if it does turn out to be the sender, so much the better if you can save the cost of paying for the new one.

Other possibilites are the fuel pump relay and the wiring to/from the pump, and it's connectors. Drop the spare to check up in the rear of the tank where the wiring is visible to see if the split loom tubing is broken up and some wires have worn against the frame.

It could be the gauges, but so far my experiences with funny fuel gauges has always been either the sending unit itself, or the electrical connectors from the unit to the vehicle wiring.

 

[Tbars4]

...If you got the unit at autozone, there are several threads here of people changing them out every month including 4 times in a few months...

...Be sure to also check your battery cable connections..

...I have seen the fuel guage do this very thing with a bad ground connection at the cables...Also keep an eye on your alt guage just to make sure it is charging everytime you drive...Another sign of this problem is that you'll look down one minute and it's charging and the next it is below normal...

 

[Willard]

I think tbars may have gotten it. I've been having a lot of wierd charging issues happening, and a ground somewhere may be the problem. Id like to get the alternator tested too as it may not be performing like it needs to
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[Anime]

Check all your battery cables for corrosion (blue/green coloring inside the wiring) on the ends. If you slice the jacket near the ends just a bit, and there's blue dust/goo all in the winding, replace the cables. (Napa has stock replacements for a good price).

If you do wind up needing a new alternator, might as well spring for the Limited's 130 amp upgraded alternator over the factory 95 amp, it's only about 5 bucks more at most places. Could be your EB already has the 130 amp too, so be especially sure not to get a 95 amp if that's the case.

 

[Willard]

The cables and alternator are fairly new. I question the alternators performance though. It's been flaky ever since it was replaced, and I swear the old one didn't do that. If I end up replacing it, I'll just do the 130 amp this time instead of the 95 amp. Just have to wait for the spare cash to do so.