gas gauge not working

[98-k1500-z71]

i was having problems with my gas gauge and truck starting in general (i would have to bang on the gas tank to get her started some mornings) so i went ahead and changed the entire fuel pump assembly. everything was good but then a day after the repair the gas gauge shot to E. whenever i start the truck the gauge goes all the way up to F and then back to E no matter how much gas there is. recently the gauge has made it to like the halfway mark before going back to E. with the key off and after sitting for a little while ill get like 1/8 tank reading before starting the truck. any input would be greatly appreciated. thank you

 

[twomanymontes]

It sounds like the float fell off the level sensor arm. Also check the ground to the sending unit. I think if the ground wire is open, it will default to empty

 

[great white]

Unplug your sender, meter the plug.

GM senders are 0-88/90 ohms.

0 is empty, 90 is full.

if you get something close to where you think your level is (IE: 1/2 tank would be ~45 ohms), the sender is not the problem.

If you have had the gauge face off recently, check to make sure the gauge contacts are still touching the PCB.

I have a variable resistor board I built use on the sender plug to sweep the needle (works for the temp sender also). If I can't make it sweep or it's inaccurate, I know it's wiring somewhere ahead of the sender.

The ground is up in the engine bay on the engine. It runs all the way back to the engine bay. Just the way they built it.

The final place (if wiring is not the problem) could be the dash plug for the cluster itself. The get misaligned if you've had the cluster out a couple times.

Or, it could the the gauge motor itself I suppose.

You just gotta get in there with the multimeter and chase it down.

 

[98-k1500-z71]

thank you for the input guys. i will start off by metering the plug and go from there

 

[98-k1500-z71]

i metered the plug last night and got around 48 ohms so i guess i have a half of a tank. i think im just going to suck it up and drop the tank again and see if the float is stuck because ive never had the dash apart or anything for it to be something in the cluster

 

[kyle1500]

@98-k1500-z71 Did you ever figure out why your gas gauge was t working? I’m having the same problem.