01 2500 8.1 Suburban Fuel Gauge Issue

[aptivaa12]

Ok I am fairly new on the site with only 1 other posting so if I'm out of line please forgive and steer me the right way. I have a 2001 Suburban 8.1 2500 with a persistent fuel gauge problem. I purchased this truck in 07 with 69,000 miles on it. Prior history is vague but all recalls regarding the fuel pump harness has already been done. Sometimes for no reason the gauge would drop to E and low fuel warning light would come on. This required a disconnect of the battery for about 10 min to resolve and then I would go about my own business for about 6 months till it done it again. Last year it dropped to E and will not return. I traded the instrument panel with my Denali temporarily for diagnostics only. It worked just fine in the Denali and the one from the Denali did the same in the Suburban. Then I installed 2 fuel pumps/with sending unit all OEM. Still no resolution. I then read alldata stats on what resistance levels should be for what amount of fuel I have. The levels where absolutely correct all the way to the PCM wiring harness. I purchased a variety pack of resistors from radio shack cut the correct lines at the harness used for the fuel sending unit and used the correct ones for E 1/4 1/2 3/4 F and they would read correctly only when the battery was disconnected for about 5 min and when I started the truck it would read correctly for about 30 seconds then drop to E. If I stop/start the engine doesn't change this. Only when the power was removed. So I removed the fuse to the ECM only and then that is where I narrowed it down. It would work just like before so I thought oh its the PCM. I purchased a used one off ebay from an outfit in Ohio that programs these to the vin and uses a tech 2 with a one year warranty. This did not fix the issue either. The new PCM does the same thing. So yeah I'm Perplexed.

[aptivaa12]

Cmon guys I really need the help on this one LOL.

[MT-2500]

Originally Posted by aptivaa12

Ok I am fairly new on the site with only 1 other posting so if I'm out of line please forgive and steer me the right way. I have a 2001 Suburban 8.1 2500 with a persistent fuel gauge problem. I purchased this truck in 07 with 69,000 miles on it. Prior history is vague but all recalls regarding the fuel pump harness has already been done. Sometimes for no reason the gauge would drop to E and low fuel warning light would come on. This required a disconnect of the battery for about 10 min to resolve and then I would go about my own business for about 6 months till it done it again. Last year it dropped to E and will not return. I traded the instrument panel with my Denali temporarily for diagnostics only. It worked just fine in the Denali and the one from the Denali did the same in the Suburban. Then I installed 2 fuel pumps/with sending unit all OEM. Still no resolution. I then read alldata stats on what resistance levels should be for what amount of fuel I have. The levels where absolutely correct all the way to the PCM wiring harness. I purchased a variety pack of resistors from radio shack cut the correct lines at the harness used for the fuel sending unit and used the correct ones for E 1/4 1/2 3/4 F and they would read correctly only when the battery was disconnected for about 5 min and when I started the truck it would read correctly for about 30 seconds then drop to E. If I stop/start the engine doesn't change this. Only when the power was removed. So I removed the fuse to the ECM only and then that is where I narrowed it down. It would work just like before so I thought oh its the PCM. I purchased a used one off ebay from an outfit in Ohio that programs these to the vin and uses a tech 2 with a one year warranty. This did not fix the issue either. The new PCM does the same thing. So yeah I'm Perplexed.

If everything has been changed on it and all other gauges are working right.
Check all plug in's and power feeds and grounds.

If you have or can get a engine /dash/body capable scanner it will have a gauge test built in it and show what the fuel sending unit level is telling the pcm.
Go threw the test and it should point you to the problem.
Let us know what you find there.