Fuel Sending Unit/Gauge - SOLVED

[RAMurphy]

Hey all, just recently started experiencing some issues with my fuel gauge readings. A little background, almost 2 years ago I replaced my fuel pump. I replaced it with the A/C Delco. What a pain in the ass dropping the tank and getting the retention ring off and back on. But I got it done. The issue: Randomly the fuel gauge on the dash will go from full to empty and stay there. I will get the low fuel warning indication when this happens. Then after awhile it will move back to full. Now this happens more often when the tank is full. Less often when less then full and almost never when the tank is below a half of tank. Correct me if I'm wrong. I seem to remember that the low fuel warning light is tied to the fuel float sensor. So my assumption is I either have a faulty sensor or problems with the wiring - not the gauge on my dashboard. Thoughts?

 

[Fless]

Agreed. No matter what the gauge needle or stepper motor shows, it has no effect on the Low Fuel light.

You could monitor the fuel level with a scanner that reads that PID to see what the circuit is reporting for fuel level.

 

[89Suburban]

I swore I just read something today about this same phenomenon somewhere on here somewhere.

 

[SilverSport]

I have read and experienced similar issues that were traced to the fuel and float in the tank and each time it has been cleared up by a dose (I double dose) Chevron Techron...

the stepper motor issue would be my first guess and using Chevron Techron Complete Fuel System Cleaner would be something I'd give a shot to next...also use Top Tier fuels when you can

good luck with your Tahoe

Bill

 

[RAMurphy]

Agreed. No matter what the gauge needle or stepper motor shows, it has no effect on the Low Fuel light.

You could monitor the fuel level with a scanner that reads that PID to see what the circuit is reporting for fuel level.

Thank you for the response, sounds like a plan and what I need to do. When it goes back to reading fuel quantity it appears to go back to the correct fuel amount. Sure hope it is a wiring issue, I don't want to drop the tank again and the rest of the work associated with getting the fuel pump unit replaced.

 

[RAMurphy]

I have read and experienced similar issues that were traced to the fuel and float in the tank and each time it has been cleared up by a dose (I double dose) Chevron Techron...

the stepper motor issue would be my first guess and using Chevron Techron Complete Fuel System Cleaner would be something I'd give a shot to next...also use Top Tier fuels when you can

good luck with your Tahoe

Bill

Thank you. I will give the dose of Chevron Techron a shot. I've always used top tier fuels.

 

[strutaeng]

Hey all, just recently started experiencing some issues with my fuel gauge readings. A little background, almost 2 years ago I replaced my fuel pump. I replaced it with the A/C Delco. What a pain in the ass dropping the tank and getting the retention ring off and back on. But I got it done. The issue: Randomly the fuel gauge on the dash will go from full to empty and stay there. I will get the low fuel warning indication when this happens. Then after awhile it will move back to full. Now this happens more often when the tank is full. Less often when less then full and almost never when the tank is below a half of tank. Correct me if I'm wrong. I seem to remember that the low fuel warning light is tied to the fuel float sensor. So my assumption is I either have a faulty sensor or problems with the wiring - not the gauge on my dashboard. Thoughts?

I've got this exact same issue on my 04 project Suburban. In my case, however, I get a code for the auxiliary tank. I don't drive that vehicle. I thought maybe the float had gotten stuck from sitting and I put fuel in it and did a few wot and braking, but didn't issue came back.

I suspect the float/sender...

With my scan tool I can see the voltage of the auxiliary tank kinda fluctuating, it's not a steady voltage.

I just happen to also have a cluster that drains the battery, but I "believe" my guages are all good. I have to fix the cluster for the battery drain issue, but I don't think that's the issue with the intermittent fuel gauge going to zero.

Good luck and keep us posted.

 

[Fless]

the stepper motor issue would be my first guess and using Chevron Techron Complete Fuel System Cleaner would be something I'd give a shot to next...also use Top Tier fuels when you can

The gauge stepper motor DOES NOT AFFECT the Low Fuel light circuit.

 

[RAMurphy]

Thanks all. An update: Ran my scan tool and although the gauge was steady and reading about 3/4 of tank (which is pretty close to accurate based on the amount of miles), I was able to pick up a stored intermittent code of P0463. Seems like I have a fuel sensor problem, although I will do some additional troubleshooting.

 

[RAMurphy]

One of the possible failure mode of this code is "Malfunctions within the PCM". I'm not experiencing any other issues so I assume this is not a likely source of the issue. Thoughts? I guess I will need to drop the tank to complete verify wiring issues. My gut, tells me this is a sending unit issue.