Replaced Fuel Sender, Gauge off by 10 gallons now.

[Tom P]

Iv had the same issue on my truck (34 gallon tank) since I bought it. Replaced the fuel pump when I thought the tank was empty. Ran the truck till the tank was empty, well when i went to drop the tank I was surprised at how heavy the tank was. Well to my surprise there was 10 gallons of gas left in the tank. Checked depth of the pickup with the tank depth and they were pretty damn close about 1/8" from the bottom of the tank. Put the new fuel pump assembly in and filled her up, ran her out of gas again and then filled it up and it only took 22 gallons, did this a few more times and it only ever takes 22 gallons to fill her up. My fuel gage is saying the trucks empty, the truck says its empty (wont even run at idle on level ground), but there is still 10 gallons left in the tank. Curious to see where this thread goes.

I think you might have a deeper issue. I assume that you have an 8 foot bed since you have the 34 gallon tank? Also what make and model of fuel pump did you use? The fuel sender picks up fuel from the very bottom of the unit. There should be a little sock that sticks out of the bottom which acts as a pre-filter. There are rubber feet on the bottom of the sender that are supposed to rest on the bottom of the tank to provide clearance as well. If your fuel pump cant suck the last 10 gallons then I'm curious as to whats preventing that from happening.

 

[bornchevy]

Its the factory tank as far as I know, the replacement fuel pump assembly was a airtex unit that I picked up at an autozone when i was in Texas, I don't have the part number anymore and autozone dose not have it listed on their website. I was going to rip the bed off this weekend and finally figure out what is wrong with the damn thing but of course one of the few times it rained in so cal this year is this weekend haha. 8' bed 1992 k2500 LD eclb (its the 6 lug 2500) worst case scenario I'm just going to weld a small sump in the bottom of the tank below the fuel sending unit sits and lengthen the unit to pick up fuel from the sump.

Tom P. Any luck on figuring out your problem?

 

[Tom P]

Tom P. Any luck on figuring out your problem?

Nothing solved yet. We went to mexico for a week and now I'm playing catch-up with about a dozen other things. My thought is its a wiring issue of some kind or just the dash cluster is old and worn out. I thought about changing the needle's position on the dash as a short term fix. It could also be an issue with the float arm itself. I didn't pay too close of attention to it when I installed the new sender but when the bed comes back off later this year, I plan to yank the sender again to double check.

I also realized that I had filled up at a different gas station than usual as well. Their pumps are finicky and wont fill tanks as full as my normal station does so when I put a full tank from my normal station again, it hung out on full for a while longer than previous.