Fuel Gauge alway "E"

[WICruiser-97]

I recently bought this '97 C1500 and among other things dropped the tank (to remove 7 year old fuel, pump made noise but would not pump out fuel) and replaced the pump and sending unit.

I now have the truck running and have put about 8 gallons of fuel into the 25 gallon tank but the gauge reads empty or very close to empty. I assumed it was a problem where the ground wire connects to the frame (rust issues) so I ran a seperate ground wire from the tank ground wire (I believe it is the ground for the sending unit) to one of the torque convertor cover bolts thinking that would be a good connection to the engine but no change in gauge response.

I am trying to avoid dropping the tank again just to confirm the sending unit function. Is there an easy way I can verify the gauge is not the problem? All of the other instrument panel gauges appear to functioning correctly.

 

[GoToGuy]

My first thought, is anything you touched is always the first place to look for a problem . Not moving at all. You changed the ground. But is it a good ground? Did you test the float a and gauge before reassemble? It's electric, recheck your work, then power and grounds, and continuety.

 

[WICruiser-97]

I agree with the tought process, just struggling with the need to drop the tank to be able to access the sending unit. I wasn't paying close attention to the fuel level with the original sending unit and pump but I do believe it was the same (stuck on E) because I recall not knowing how much old fuel needed to be removed (was about 1/2 a tank).

I can confirm the ground I added is good.

If I understand the problem people are having when it always reads full it is a bad ground so I may be going at this all wrong. If I disconnect the ground should the gauge go to full?

 

[WICruiser-97]

If I understand the level sender wiring if I ground the purple wire going to the sending unit the gauge should go to full (or past full). If this is correct it would be a way to test everything involved except the sending unit.

 

[WICruiser-97]

As an FYI, even though I have put about 9-10 gallons of fuel in the empty (dry) tank I ran out of fuel after only driving about 50 miles so I am speculating that the fuel pump/sending unit that I installed is ready empty in regards to the actual fuel available. I have been resisting adding too much fuel in case I need to drop the tank again but I think I may just bite the bullet and add 10 gallons or so to see if the gauge comes up to something reasonable.

 

[WICruiser-97]

Added 10 gallons of fuel and the gauge shows a little over 1/2 tank.

I am guessing that the fuel pick-up and float drop on the after market sending unit agree with each other, just the first 5 or so gallons on fuel in the tank are not usable.

Thankfully it appears there will not be a need to drop the tank.

 

[Erik the Awful]

I'd clean the spot on the frame for the ground and make sure your sending unit's ground terminal is clean and tight. Also, check to make sure you have 12v going into the sending unit. If you have a corroded connection you could have less voltage going in, which would have the same affect as a bad ground.

 

[Pinger]

If I understand the level sender wiring if I ground the purple wire going to the sending unit the gauge should go to full (or past full). If this is correct it would be a way to test everything involved except the sending unit.

On my to-do list for my 1999 Suburban is to find out why when it is started the fuel gauge goes full scale despite the tank being only half full.

If I understand the level sender wiring if I ground the purple wire going to the sending unit the gauge should go to full (or past full). If this is correct it would be a way to test everything involved except the sending unit.

That would be my thinking, but I'm near certain that I recently read on this forum that a broken wire sends the gauge to max reading....
Mine only does it immediately after starting the engine and gradually drops back to the half way mark.

 

[WICruiser-97]

FYI, I filled the tank yesterday and the gauge went to full so I bleieve the problem all along was that starting from a dry tank it takes a fair amount of fuel to get high enough in the tank for the gauge to read and the pump to provide fuel.