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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: ssapach on September 12, 2011, 10:11:49 pm

Title: Fuel Gauge Sending Unit
Post by: ssapach on September 12, 2011, 10:11:49 pm

So before I get the box back on my truck I'd like to sort out my sending unit issue.  My passenger side tank seems to be working, when I switch to that side it drops to empty (it's bone dry currently).

When it's switched to the driver's side, it goes up to over full but there is only about 5 gallons of gas in the tank right now.  When I unhook the ground it goes farther over full and when I hook the ground back up it drops back to just over full.

I had the sending unit out of the tank before I put the tank on the truck and the sending unit seemed fine.  The float wasn't sticking at all and it looked clean as if it were new.  Is it possible that the float got stuck at the top of its travel since I reinstalled it in the tank?  Or could it be that the sending unit itself is just no good?

Title: Re: Fuel Gauge Sending Unit
Post by: Irish_Alley on September 13, 2011, 01:16:08 am

can you swap the units and see how they work then? doesn’t have to be in the tank just hook the wires up.

Title: Re: Fuel Gauge Sending Unit
Post by: ssapach on September 13, 2011, 12:39:57 pm

I swapped the wires around and it was doing the same thing as before.  Just over full all the time.

So I figure it's as good of time as any to remove the tank and pull the sending unit.  Hooked up the wires with the sending unit out, if I move the float to the empty position it goes to empty on the gauge.  But pretty much anything above and beyond 1" of travel from empty, makes the gauge go to full or just over full.

Move the float back to empty, gauge keeps going back to empty.

I tried a few times, all with the same results.  Pretty much anything above empty makes it show a full tank.

Does this sound like the sending unit is screwed?

Title: Re: Fuel Gauge Sending Unit
Post by: Irish_Alley on September 13, 2011, 01:12:09 pm

can you put a tester on the gauges circuit and see what its saying i think ohms should work

Title: Re: Fuel Gauge Sending Unit
Post by: ssapach on September 13, 2011, 03:59:36 pm

Put a tester on the sending unit, shows 0 ohms at empty and anything above empty it jumps around all over and won't give a proper reading.  If I'm not mistaken it's supposed to be a 0-90 ohm sending unit.

Title: Re: Fuel Gauge Sending Unit
Post by: Irish_Alley on September 13, 2011, 04:33:26 pm

0-90 sounds right

Title: Re: Fuel Gauge Sending Unit
Post by: ssapach on September 14, 2011, 04:21:21 pm

New sending unit came in this morning.  Hooked up to the wires just to try it out.  Works like a charm now!

Problem solved.

Thanks for the input!

Title: Re: Fuel Gauge Sending Unit
Post by: Captkaos on September 22, 2011, 11:16:13 am

was going to say if you are reading over empty typically the sending unit is shot. 

Title: Re: Fuel Gauge Sending Unit
Post by: rainman15 on September 24, 2011, 03:23:44 pm

About how much was the new sending unit? 

Title: Re: Fuel Gauge Sending Unit
Post by: ssapach on September 25, 2011, 10:49:27 am

Cost me $120.