Fuel Needle Misbehaving- Stepper Failing or Something Else?

[gpking]

Last week I put about 900 miles on the TB over a period of four days. A majority of that distance was accumulated driving almost non-stop from Maryland to North Carolina and back.
On the way back home on Sunday it was a miserable 100 degrees on the Interstate according to the TB. At one point, about 7 hours in after turning on the a/c, I looked down at the gauges and noticed my fuel had dipped down all the way below E, and the fuel level warning light was on but the chime hadn't sounded. I was only 1/4 of the way into Virginia, so I knew I should have well over 1/2 of a tank. Then after maybe two minutes, the fuel gauge did a sweep all the way to F, then returned to around 5/8ths and gradually returned to where the fuel level actually was.
It freaked me out a little at first because I was expecting something went bad, but it just fixed itself and has been working since.
It's probably nothing for me to worry about, but could this be the sign of a failing stepper motor?
My dad's Silverado had 3 steppers start working intermittently before they failed, and his truck was only 8 years old at the time. My TB turns 12 this December.

I want to believe it's the stepper motor (since the chime didn't go off for low fuel), but I don't want to rule out anything else, or that maybe it was just a random occurrence and nothing is wrong.
Thanks in advance for your opinions.

 

[Blckshdw]

I would suspect the stepper motor has it's end in sight. As recommended in other threads, when you get ready to change that one, might as well change them all while you've got the cluster taken out and apart.

 

[Mooseman]

It could also be the fuel level sensor in the tank. To confirm which one is failing, you would need an OBD2 reader that can display live data, including fuel level directly from the sensor, independent of the gauge/stepper motor. An ELM327 with the free Torque app (on Android phones or tablets) works well and is inexpensive. If the fuel level is stable from the direct reading, then the stepper motor is toast. If just as jumpy, then the sensor needs to be replaced.

I'm leaning towards the sensor because the LED is lit by the BCM independent of the stepper motor.

 

[stvrob]

Mine did what you descibed and then crapped out for good. Several years ago. It hasnt worked since. There is a recall on the fuel level sender for my 06, but its over the milage limit and they refuse to do the recall work.

 

[BlazingTrails]

It is very common for the sending unit to go bad in the tank. Mine did the same thing and that's what I replaced.

Edit: http://gmtnation.com/forums/index.php?/topic/5525-Fuel-gauge-problems.-Cluster-or-sending-unit-???

 

[Jay Bird]

+2 on the fuel sending unit. Mine went bad on my 05 TB and my son and replaced it. That took care of the fuel gauge issue.
Then 2 days after we replaced it I received a letter from GM, they will replace the fuel sending unit on a vehicle less
than 10 years old and 120,000 miles. Also had a form in the letter for anyone who had the sending unit replaced. Fill out the form and take it and the receipts to your GM dealer and get reimbursed.

 

[stvrob]

Yea. My 06 had 130,000 miles when we got that letter, but it had already been dead for two years prior to that.

 

[gpking]

I almost forgot about this thread- thanks for all of the replies guys.
All of my steppers are fine and they zero-out with the ignition off (unlike my dad's truck which is on its second set of failing steppers), so I am guessing the fuel level sender may be getting ready to go sometime soon. All of the different factors like the long drive, high temperature, a/c running, etc made me thing it could have just been a random glitch.
Over a week later it still is behaving normally so I don't want to replace it just yet.

Unfortunately 2003 TBs have no fuel sender unit recall (just a whole bunch of other nonsense about airbags not working, shrapnel flying around in the cabin, and front brakes not working) so we'll wait and see.
Whenever my neighbor gets back I'll hook the TB up to his Solus Ultra and see what's going on.

Thanks.

 

[stvrob]

I am going to drop the tank on my 06 trailblazer EXT today. (After living with no gage for the past 3 years). I have a Dorman replacement fuel sender unit. Just took 3 ibuprofen's to check the arthritis in my shoulders. Wish me luck.

 

[BlazingTrails]

I am going to drop the tank on my 06 trailblazer EXT today. (After living with no gage for the past 3 years). I have a Dorman replacement fuel sender unit. Just took 3 ibuprofen's to check the arthritis in my shoulders. Wish me luck.

You got this brutha

 

[stvrob]

Fuel sender replaced. Job complete. Dropping the tank is not so bad, except for those fuel line clips.

 

[Mooseman]

Man, you gotta get the good stuff... Celebrex.

Good on ya getting it done. Any pain?

 

[stvrob]

Pain was held at bay until the job was finished. It's usually worst in the middle of the night and in the morning.

 

[gpking]

I got the TB hooked up to my neighbor's scanner yesterday.
The needle was reading halfway between the uppermost tick mark and the "F" (about 30miles driven so far).
The Tripometer read 32.6 miles, so the needle seems correct, however, the scanner said the vehicle was reporting 89% of a tank, which isn't completely accurate, but it's close.
40 miles is 10%.
Nothing to worry about yet.

 

[TimRXUV777]

Pain was held at bay until the job was finished. It's usually worst in the middle of the night and in the morning.

Glad to hear that the back pain was kept at minimum, but what about the gauge? Fuel gauge working as normal?

 

[stvrob]

Yes. The gage works fine. But now I have the evap code. I am certain I plugged it back in!

 

[Mike w]

I too had this problem but when I dropped the tank I broke the tank pressure sensor^_^:angry:

 

[Mooseman]

That or a wire broke?

 

[BlazingTrails]

How did this project turn out?

 

[HARDTRAILZ]

Fuel sender replaced. Job complete. Dropping the tank is not so bad, except for those fuel line clips.

How did this project turn out?

Looks like it was completed...