Good job on the battery feed wire to the alternator!

Fuel gauge indicating past full means there's an open circuit. For example: Broken signal wire or ground wire, or a connector unplugged, could even be a faulty level sending unit. The open circuit could be anywhere from the fuel pump module connector to the PCM. If you're not getting a DTC for a MAP sensor or inlet air temp sensor, the ground splice pack by the rear bumper would be the first place to look for a problem. Black connector with a blue connector plugged into it. They are all ground wires that ground in different places on the vehicle. Take it apart and clean the terminals. Post your results.

 

Interesting. I have two places to start then, as I just installed the fuel pump about 3 months ago. I haven't put the air ducting back on the truck yet, since I wanted to make sure everything was go before I put it back, so the air inlet temp sensor is still disconnected. As for the rear wiring, I am pretty familiar with it since I couldn't turn the bolt to undo it when I first took the bed off to do the fuel pump. It is possible I did a crap job of splicing that back together after I cut it, but I assumed those were strictly the brake light/turn signal lines. I'll take a look and maybe redo that splice again. Funny enough I WAS able to undo the bolt while adjusting the bed when I bolted it back on, so that should be an easy thing to check as well. I hope the fuel pump connections aren't the problem, cause that stuff is expensive! I'll put the ducting back, plug in the air temp sensor, put in the key, then if still no help, I'll check out the wiring on the back end, clean up the grounds back there and report back. Thanks for the response!

There is no 'check engine' light on at present.

 

The fuel level sender does not ground in the rear, but the fuel pump does. The level sender ground goes through the ground splice pack and then splices to the MAP & IAT grounds near the underhood fuse panel. From that splice, it goes to ground, I believe at the rear of the right cylinder head. If that ground is poor, the MAP & IAT would set DTC's. That will be your clue as to where to start looking for a poor connection: No DTC's = poor connection BEFORE the level sender splices near the underhood fuse panel. In other words, probably in the rear of the vehicle.

 

Well I decided to hold off on this a day just cause I'm tired of screwing around with my truck LOL, and went to get some lunch, stopped and put twenty bucks of gas in (about enough to bring it to half a tank), reset my trip meter so I would know to put more gas in at 100 miles, then lo and behold, driving out the fuel gauge starting working again. Ran a few errands, gonna check the battery and alt charging again over the next few days, just to make sure all the connections are good and it's still going.

 

Made it to work and back, and she drove like a charm, better than she has in a few years. No problems with the charging or the fuel gauge. Only thing I notice is a slight burning smell, which I attribute to some coolant probably burning off that spilled on the engine block (I had to detach the coolant hose to get the stupid air ducting back on tight), I've noticed a similar thing when changing the oil if I spill a bit on the engine. Hopefully it is not a big deal. I can't seem to find any specific source for the odor.

 

Keep an eye on it, these things rarely fix themselves... but if it does... hang on to it!

The odor could be coolant dripping on the exhaust from a leaky intake manifold gasket.

 

Just checking back. Still no problems, so I'm very hesitantly giving a nervous thumbs up, which means something else is probably about to go on my truck! After getting this figured out, I started my week of vacation this week with 2 smaller and easier repairs, I did the blower resistor thing (replaced resistor and plug) as well as fixing my door handle (a matter of fishing out the screws that fell in the door panel and screwing the drivers side handle back on). It's beginning to look like a normal vehicle again, and she'll be all mine if I can just keep her going for 3 more months til the payments are done