Fuel tank?

[frotosride]

Ok so just a few questions on fuel tanks. One with the dual tank factory system are the sending units the same and just clocked differently? If not then which tank is considered the auxiliary tank? The reason I ask is because I am going to replace the right tank pump and sending unit but the replacement parts that I have found only list "main tank" and "auxiliary tank" and I don't know which is which. my gut tells me that the right side is auxiliary but I dn't want to find out the hard way it's not after I drop it and nothing fits right.

[frotosride]

Also while I'm throwing out fuel related questions here's another with I'm sure more to come. Ok So I also plan on replacing my gauges. The specific fuel gauge that I plan on can be set to operate on multiple ohm inputs...0-90ohm empty-full is the closest one for the OEM sending unit which according to the tech pages ~1-88 ohm empty-full. Will this gauge give me an accurate reading or is it possible to adjust the sending unit 90ohms?

[bd]

Left tank is main - original sending unit is GM P/N 25090846 (Dorman P/N 692-027).
Right tank is auxiliary - original sending unit is GM P/N 25090837 (Dorman P/N 692-044).

The tanks are interchangeable, side-to-side.  The fuel pumps are interchangeable, side-to-side.  But, the sending units are dedicated left (main) and right (auxiliary).

On the fuel gauge specification, 0-90 ohms should work nicely.  The resistance value of factory sending units is non-adjustable.

[frotosride]

Thanks a lot. That mean I got the right sending unit for the right tank. I will replace the left one later after I put the lift and TBI rebuild and new front rotors.

[Dirka]

Quick question, I have dual tanks on my 77 K10 driver side is working just fine. The passenger side, not so much, I do not the issue, but the best route to get it working.. new sending unit? Do I need to take the tank off for anything, I do not know how long it has not been working and thus if any residual fuel has been sitting inside of it.
Thank you

[81_Chevy]

Quick question, I have dual tanks on my 77 K10 driver side is working just fine. The passenger side, not so much, I do not the issue, but the best route to get it working.. new sending unit? Do I need to take the tank off for anything, I do not know how long it has not been working and thus if any residual fuel has been sitting inside of it.
Thank you

im having a hard time figuring out what your problem that you stated. is the tank not sending fuel? is the gauge not working? please explain a little more. and consider starting a new thread as well                                               

[frotosride]

81-, I really am done with the thread so I don't mind Dirka taking it over.

 Honestly, if it's been  as long as you say its been then I would open the tank and clean it out as best as you can. Other wise you may just have a lot of fun changing fuel filters over and over again as trash chokes fuel to your carb. It wouldn't hurt to replace the sending unit but if you look in the Electrical part of the forum I do believe that there are OHM readings for the different positions of the sending unit. This will tell you if you need a new one and besides if you clean the tank the way you should, then you will need to take it off the truck anyway. Good luck.

[Dirka]

Thank you froto!
I do not know the exact problem myself either because the truck hasn't run in close to a year(another forum issue I will be starting soon) I just needed a good place to start with getting that second tank in a place to test it once I get the truck to running order.  The previous owner said is wasn't working and never really got a chance to test it before I took the top end apart for cleaning and what not. 

[frotosride]

Thank you froto!
I do not know the exact problem myself either because the truck hasn't run in close to a year(another forum issue I will be starting soon) I just needed a good place to start with getting that second tank in a place to test it once I get the truck to running order.  The previous owner said is wasn't working and never really got a chance to test it before I took the top end apart for cleaning and what not.

No problem, Just thought of something and is't a simple fix and cheap. The tank selector switch is a very common weak link because of the plastic pice that actually moves the internals of the switch wears out. I recommend checking this or just completely replacing it since its only about $20. But If this gets it working I stil highly recommend replacing al filters especially the intank sock on the pump pickup.
 Other than this tank are you having issues getting the engine to start or just waiting on parts to do so?