Fuel gauge reads "E" at all times

[Phantom240]

Okay, fellas, I have a question regarding the infamous string of fuel gauge related problems we OBS owners seem to experience. I have a '99 Denali that always reads empty. I've only seen the needle move a couple of times (not vibrating like the "hummingbird" issue), and even then, it only came up a slight bit before coming back down to "E". I put ten gallons in the tank over the weekend, thinking it would come up to about a quarter tank, but got no reading still. When I turn the key to the run position, the needle rockets toward "F", then goes back to "E". I'm thinking the gauge might be bad. Here's what I'm thinking: I'll take it over to my friend's shop and put it on the lift, and disconnect the fuel sending unit. If I'm understanding the system properly, then it should read full when the circuit is open, assuming the gauge is good and I don't have a short in the harness. Am I correct in this assumption?

 

[SunlitComet]

litt bit more complicated then that starting in 1998 the fuel indication system runs thru the pcm .

Fuel Gauge Inaccurate or Inoperative Fuel Gauge Inaccurate or Inoperative

Diagnostic Aids

• Verify that the fuel level is in the same range as the customer concern.
• Use the fuel level sensor resistance in order to verify the fuel level sensor operation. When the fuel tank is empty, the fuel level sensor resistance is approximately 40 ohms. When the fuel tank is full the fuel level sensor resistance is approximately 250 ohms.

Test Description

The number below refers to the step number on the diagnostic table.


22. DTCs will set in the PCM when you perform this diagnostic table.

 

[Phantom240]

You are a freaking GMT400 god, good sir. I see it mentions primary and secondary fuel level sensors... I'm not familiar with this. Any info you can share?

 

[SunlitComet]

ignore the secondary sensor info the same info is used for suvs and trucks of which some trucks have dual tanks.

 

[Phantom240]

Ah right. Now whats this about a cluster check?

 

[SunlitComet]

You asked for it.




System Check - Instrument Cluster
Initial Inspection and Diagnostic Overview
Instrument Cluster System Check


Instrument Cluster System Check (Part 1 Of 2)


Instrument Cluster System Check (Part 2 Of 2)

 

[_Dylan_]

The Denali cluster I got from the junkyard does almost the same thing except doesn't read much past 1/4 tank. The needle spins freely when I took the cluster apart.

 

[Phantom240]

I'll post up a video this evening of what it does.

 

[Phantom240]

Here we go

 

[_Dylan_]

hmm. I don't recall mine going bananas like that when I turned the key on.

I would say it's part of the cluster. My stock cluster in my 97 works fine, but when I put in the 99 denali cluster the gauge doesn't work right. The cluster had 280,000 miles on it also...

I would try getting a cluster from a low mileage truck in the junkyard if you need the fuel gauge. Just temporarily until you can find whats wrong with your cluster.