Tank sending units

[Muddytazz]

Does anyone know if a specific sized gas tank sending unit has to match the gauge or vice versus? What I'm getting at is if you have a 31 gallon tank and sending unit and a gas gauge from a rig with a 40 gallon tank, will it read funny or should it read correct?

 

[ntaj*ep]

As long as the pick up dosen't interfear with the bottom of the tank and your senders have the same resistance your fine....

 

[dyeager535]

AFAIK, all GM fuel gauges/senders operate the same way, so as was stated, as long as the depth of the tank is the same, your readings will be the same.

 

[Muddytazz]

Reason I ask, is cause 2 yrs ago when I did the body swap on my dads burb. His was a 77 with a stock 31 gallon tank and sender. I swapped on a 81 body from a 2wd that had a stock 40 tank and sender. So needless to see, I just left the stock 81 gauges in place. Now, I'm driving it around right now cause my burb is in the tranny shop getting fixed and if I fill up the tank with gas, the needle will move from FULL to 1/4 almost as fast as the speedo needle, then from 1/4 to EMPTY will take forever to move. Any ideas?

 

[sickquad]

Sounds like your sending unit has an issue. I am running a big tank with the sending unit from a small tank so when it shows empty I still have a few gallons left. I just use mileage to track how much fuel I have. It's pretty accurate from tank to tank.

-Chris

 

[78blazaer]

My sending unit on my 78 Blazer is acting up.. Do you guys know where I can purchase a replacement sending unit.

Thanks in advace,
Tav

 

[akbound]

I just got mine from LMC. www.lmctruck.com

 

[MarcS]

I think it will read wrong. This site might help.

http://tanks-to-pans.com/site/823208/page/45029

 

[dyeager535]

For the price, I'd try to "fix" yours. The info has been posted here before, but essentially, there is only one piece that you can disassemble/celan once its pulled from the tank.

Didn't make mine *perfect* but it reads much closer to full/empty now.

 

[Muddytazz]

For the price, I'd try to "fix" yours. The info has been posted here before, but essentially, there is only one piece that you can disassemble/celan once its pulled from the tank.

Didn't make mine *perfect* but it reads much closer to full/empty now.

I know the sender is working perfect as it was working just fine on the 77 gauge, its just the 81 (40gal)gauge that is reading funny, thats why the ? about if gauges and sender size have anything to do with each other.

 

[dyeager535]

That was for the guy that was having problems and asking where to buy replacements. Half the time, it seems the sender isn't the problem anyway.

I can confirm a bouncing needle is a gauge issue though.

Should be able to read resistance if you pull the tank sending unit wire under the truck, the one in mine had a connector near the tank I could disconnect. The range is 0-60 or 0-80, can't recall which off the top of my head. In any case, half tank will be 30 or 40. I believe no resistance=full, which can be tested by grounding the tank sending unit wire.

Heck, so I didn't waste time dropping my tank, I hooked up a spare sender (and then a gauge) external of the truck, so I didn't have to drop the tank or disassemble the cluster.

 

[78blazaer]

Thanks for the info.