Fuel Pump or Fuel Gauge?

[Zipper369]

Hey guys, I'm new to this forum. In the past day reading through discussions here, I've already learned a new few things about my Tahoe. Anyway, on to my question...

So, I've got a 99 Tahoe LS 4-door 4x4 OBS. My gas gauge has the common "hummingbird" shake. Now, regardless of the vibration, it still reads fairly accurate. I've read elsewhere on here that it's usually caused by a bad stepper motor in the gauge cluster. That may very well be the case, but I remember a few years back the fuel pump was replaced by some gas station shop (we were on a road trip when it went out). This thing is loud. Every time I start or kill the engine, I can hear the pump running. Actually, it's so loud that with the engine running at idle, I can still hear the pump outside the vehicle. As far as I can remember, the gauge has had the shake ever since we got the pump replaced.

I don't think that anyone can answer this with any degree of certainty, but I'm just asking for opinions. Is the gauge shake most likely the stepper motor or the fuel pump/sensor?

 

[justimagination]

:welcome:And the best answer I can give you, replace the fuel pump along with the in-line fuel filter, better use AC Delco if you want it right. I just had my local NAPA shop do mine, all problems solved. Good luck,
david g............:waytogo:

 

[lesterl]

OEM pump all the way...... I cant hear my pump run, but the flowmaster is on it to help drown out the rear end howl.......

 

[NousDefions]

Mine still shakes after putting in an OEM fuel pump. I just deal with it, but I suspect it is the stepper motor.

 

[Jounier11]

:welcome: Stepper motor indeed i replaced whole fuel pump assy and still has hummingbird problem so take it to a cluster place should solve the issue

 

[lesterl]

I havent been able to find stepper motors for anything older than about 2001... I suspect maybe they still use a linear guage motor like older cars..... my 95 diagram shows one in mine..... IDK. If that is the case and it is a shake, does the shake get better if you rev the engine up (change shake speed?) How about if you unhook the belt off the engine for a bit (dont run it long that way- trying to eliminate the alternator....)

 

[Zipper369]

Lesterl, I'll have to watch it next time I go somewhere. As far as I can remember, I think the shake stays constant throughout all engine RPMs. As far as the alternator goes, I'm pretty sure that was replaced a couple years ago. Also, I have a couple capacitors in the back for my subwoofer amp. They should help keep the voltage steady... well, steadier anyway.

 

[lesterl]

I wonder if a cap across the line for the guage would help perhaps a 1000uf cap that would help steady out a varying signal from the gas tank and if it decreased the wiggle you would know it was the sender, if no change then the guage. Voltmeter on the line would also tell us if the voltage was fluctuating....

 

[Zipper369]

Hmm, that's a really good idea. I'll have to test that out on the next warm day we get.