Well, I broke the shield a little more putting it back in, but it's no big deal.

Anyway, got the pump successfully installed, seems to be working okay. Drove a total of 200 miles so far, no issues pump wise. I gotta say, maybe it was just because it was different, but it seemed like the two door tank is harder to drop than the four door. At least with the four door the fuel lines are accessible if you remove the under mounted spare tire.

Except.... now my fuel gauge isn't working properly, and I think I know why, but wanted to check here first. I drove over 100 miles in one day after filling the tank, and the gauge barely moved from full. I did manage to get 20 MPG when I usually got 18, but still, it should have moved a little after the truck burns over 4 gallons of gas. When I was soldering the new harness for the pump, I used a pair of vise grips to keep all the other wires out of the way while I was soldering. Bad idea, since I pinched the wires too tight, and the purple wire which carries the fuel level signal was squished a little. The connection didn't seem to be broken at all, just a little squished. The only reason why I'm questioning if that wire being damaged possibly is the reason why the gauge is messed up is this: After I put everything back together but before I went to the gas station to completely fill the tank, the gauge seemed to be acting normal. It showed about 1/8 of a tank, which was about the amount I removed from the tank before starting the job and what I put back in when finished. Is it possible at all that after filling the tank that the float arm got hung up somehow and that's why it's inaccurate now? Or is it most likely that wire that is causing this? If it's the wiring I can probably repair it without completely dropping the tank again so any opinion would be appreciated. Thanks

 

If the level sender wires, (purple or black) are open, (disconnected) the dash unit will indicate over full. If the purple wire is shorted to ground, the dash unit will indicate below empty. It doesn't sound like you have either problem, which could indicate a problem with the level sender: either the float is stuck, or the sender is faulty.

 

Great, so that means totally dropping that tank again. The gauge kind of seemed to move, but like I said it never moved below full after driving 100 miles. It did move around a little when on different inclines, so I assume that wouldn't happen if it was a wiring issue? And like I said, the gauge was correct before filling it up. So unless the wiring broke between my house and the gas station, it's the float or the sender. Was thinking of tapping the tank with a hammer to see if that would free it up. I did check for free movement before I installed it. I wonder what it's stuck on? While I have the tank down again I might as well repair that pinched insulation so I don't have to worry about it.

 

If the purple wire shows low resistance to ground, (barely touching ground) but not shorted out, the dash unit would tend to indicate lower than what's actually in the tank. If there's a poor connection in the purple or black wires, the dash unit would tend to indicate higher than what's in the tank. Gonna need to look very closely at the wiring. I would suspect the level sender is faulty. Just out of curiosity, what brand pump module did you install?

 

The pump is an ACDelco from Rock Auto. So even with the gauge seeming to be accurate before I filled the tank, you still think it's a faulty sender?

Oh yeah, before buttoning everything up I wrapped the area of the purple wire that got pinched with electrical tape. All the solder joints have heat shrink tubing, and I packed everything back up in the wire loom. The gauge worked perfectly before with the old sender installed.

 

It's entirely possible for it to be accurate at low fuel levels, and inacurate at higher levels. As the float moves up and down, the "wipers" in the level sender move across windings that create different resistance values for the dash unit to interpret.

 

So is ACDelco going to try to give me a hard time if I try to make a warranty claim on this thing? I guess I still will have to drop the tank again to make sure the wiring is okay and the float isn't hung up. And then drop it AGAIN to put in the new pump if they'll give me a new one.

 

Check it out as best you can. If you don't find any wiring problems, and the float moves freely, Rock auto should warranty it for you.

EDIT: When the tank is out, plug in the module and move the float up and down while an assistant watches the dash unit, needle should move smoothly up and down.

 

Okay, thanks for the help. If I got a bad unit hopefully they won't give me a hard time, I bought it back in July when I had the money but no time to install it, it was sitting in the box this whole time.

 

One quick question. When I test to see if the gauge needle moves smoothly when I move the float up and down, should I remove the pump relay before turning the key to "on"? I assume it's not good to run the pump dry, or will it not make a difference?