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[Gee_Emm]

Hi, first post here looks like a cool site.

 

Im not sure if this is the proper place to post this or not but I will give it a shot.

 

 

On a 99 Denali upon starting the engine the gas gauge pins all the way to the right then returns to the normal position.  While it is running the gauge "flutters"  as in shakes really fast.

 

Anyone know what would cause this and the fix or know where I could find the answer.

 

Thanks.

[cowboy02]

welcome to the forum...........

 

As for your question could be just good old fashioned needle bounce....  Maybe you got a lot of static in your truck

 

Take it back to the dealer and have them look at it, still under waranty right?

[CMNTMXR81]

Loose connector on and/or bad fuel sending unit.

 

This was a common problem on the old C/K truck.

 

The only other purported fuel gauge problem is if it read empty or full all the time, which is then a either a VCM connector to the IP cluster or the IP cluster itself.

 

The fluttering leaves me to believe it could be the sender.  But that's just a guess.  Is the Service Engine Soon light on too?  If so, it's likely a P0461, P0462, and P0463 code is generating it.

[Gee_Emm]

There is no check engine light on, warranty was gone long ago and this problem just started about 2 weeks ago.

 

Could it be condensation getting into the connector?  It has been way cold up here and I pressure was the truck at the car wash and wash underneath it.   The fluttering of the needle is really fast and it doesnt move that much, its like you are looking at it without glasses on, it looks fuzzy.

 

 

 

Thanks for all the replys.

 

Btw, is this site a little on the slow side for loading or is it just me?  

[AllGMV8]

I have the same problem with my 98 'Burb.  The gas gauge needle vibrates so fast it looks fuzzy.  It bugs the crap out of me.

 

So where does one start looking for this loose or bad connection?  Gas tank area, behind the gauge cluster or somewhere in between?  And how would you test the sender to determine whether it's bad or not?  

 

Thanks,

Adam

[CMNTMXR81]

As I think about it, it sounds more like an erradic fuel gauge rather than anything to do with the fuel pump, regulator, pressure or level sensor.

 

Here is the procedures for both a fuel gauge indicating low and high.  There is nothing I could find on "fluttering" or erradic needle activity.

 

Fuel Gauge Always Indicates Empty Gas

Step

 

Important:

Before performing the diagnostics below, perform a diagnostic circuit check and repair DTC's P0461, P0462, or P0463 pertaining to the fuel tank senders.

 

 

Step 1

 

Did you perform the Instrument Cluster System Check?

--

Yes: Go to Step 2

No: Go to Instrument Cluster System Check

 

Step 2

1) Remove the IP Cluster.

2) Disconnect Vehicle Control Module (VCM) connector C1.

3) Connect a J 39200 DMM (continuity) between cavity 9 of VCM connector C1 and ground.

 

Is contintuity present?

--

Yes: Go to Step 3

No: Go to Step 4

 

Step 3

 

Locate and repair the short to ground in CKT 30 (PPL) between VCM connector C1 and the IP Cluster. Refer to Wiring Repairs in Wiring Systems.

 

Is the repair complete?

--

Yes: Go to Instrument Cluster System Check

--

 

Step 4

Replace the I/P Cluster. Refer to Instrument Panel Cluster (IPC) Replacement .

 

Is the repair complete?

--

Yes: Go to Instrument Cluster System Check

 

Fuel Gauge Always Indicates Full Gas

 

Important:

Before performing the diagnostics below, perform a diagnostic circuit check and repair DTC's P0461, P0462, or P0463 pertaining to the fuel tank senders.

 

Step 1

 

Did you perform the Instrument Cluster System Check?

--

Yes: Go to Step 2

No:  Go to Instrument Cluster System Check

 

Step 2

 

1) Remove the IP Cluster.

2) Disconnect the Vehicle Control Module (VCM) connector C1.

3) Connect a J 39200 DMM (ohms) between cavity 9 of VCM connector C1 and cavity 16 of the IP Cluster.

 

Is the resistance greater than the value given?

 

Specified Value = 0.5ohms

--

Yes: Go to Step 3

No: Go to Step 4

 

Step 3

 

Locate and repair the open or cause of resistance in CKT 30 (PPL) between VCM connector C1 and the IP Cluster. Refer to Wiring Repairs in Wiring Systems.

 

Is the repair complete?

--

Yes: Go to Instrument Cluster System Check

--

 

Step 4

Replace the I/P Cluster. Refer to Instrument Panel Cluster (IPC) Replacement .

 

Is the repair complete?

--

Go to Instrument Cluster System Check

 

Instrument Cluster Check Procedure

Instrument Cluster System Check

 

Step 1

 

1) Start the engine.

2) Observe the engine oil gauge.

 

Engine oil pressure should read within the normal range.

 

- Engine Oil Pressure Gauge Always High .

- Engine Oil Pressure Gauge Always High .

- Engine Oil Pressure Gauge Always Low .

- Engine Oil Pressure Gauge Always Low .

- Engine Oil Pressure Gage Inaccurate or Inoperative .

- Engine Oil Pressure Gauge Always High .

 

Step 2

 

Observe the fuel gauge.

 

The fuel gauge indicates the correct fuel level.

 

- Fuel Gauge Always Indicates Empty .

- Fuel Gauge Always Indicates Empty .

- Fuel Gauge Always Indicates Empty .

- Fuel Gauge Always Indicates Full .

- Fuel Gauge Always Indicates Full .

- Fuel Gauge Always Indicates Full .

 

Step 3

 

1) Ensure the engine is at operating temperature.

2) Observe the engine temperature gauge.

 

The engine temperature gauge indicates the correct engine temperature.

 

- Engine Coolant Temperature Gauge Always Cold .

- Engine Coolant Temperature Gauge Always Hot .

- Engine Coolant Temperature Gage Inaccurate or Inoperative .

 

Step 4

 

Observe the voltmeter.

 

Voltmeter indicates a charge of 13 - 14.5 volts.

 

- Volt Gage Inaccurate or Inoperative .

 

Step 5

 

Observe the tachometer.

 

The tachometer indicates the correct engine speed.

 

- Tachometer Inaccurate .

- Tachometer Inoperative .

- Tachometer Inoperative .

 

Step 6

 

Drive vehicle at 30 mph (48 km/h) over a known distance.

 

The speedometer and the odometer operate properly.

 

- Speedometer Inaccurate (J 38522 Unavailable) .

- Speedometer and/or Odometer Inoperative .

 

* Refer to the appropriate symptom diagnostic table for the applicable abnormal result.

 

In step 2 in the last procedure posted, when I link to to any of the "- Fuel Gauge Always Indicates Empty." or "- Fuel Gauge Always Indicates Full ." I get routed back to the first two procedures I posted.  So unfortunately this is one of those cases where you have to use the procedures to dig deeper into something that's causing the issue.