How to clean fuel level sender boards

[Notthenow]

Hi all, new to forum, have been the repair guy for daughter's 2006 auto GT for about 7 years. Car has about 167,000 miles and actually runs well except this fuel gauge issue and the dreaded battery dying. I added quick connectors for a battery tender and that took care of the problem, well manages it. The car has the fuel gauge issue wherein just sitting running without any movement the gauge suddenly goes to E and the dreaded fuel level error code pops. She has learned to fill up by mileage, but the car won't pass emissions here in Tucson with any sort of code. I replaced both units about five years ago and the gauge was good for a short time. Several bottles of Chevron fuel system cleaner had no effect. She did have the flooded passenger side flood from the wiper valley drain being plugged. I fixed that. Later I removed the SJB and cleaned the mild corrosion off the terminals, but no improvement. I thought I would next try cleaning the sender boards. I read somewhere somebody used a pencil eraser...
When I replaced the stock units I used Motorcraft for both.

Thoughts?

 

[GriffX]

Did you open the SJB? I had water issue and found a lot of corrosion on the SJB board (I got brake light problems) after cleaning it was gone.

 

[Notthenow]

I did not open the sjb. I will take a look. Any trick to it? I wasn't aware you could.

 

[Notthenow]

Opened SJB, no real difference on posts. Pulled pump and jet pump. Ohms th3 same on level swing of floats.

 

[GriffX]

Problem with the cables/connectors? Or the stepper motor of the cluster? I once had a bad cable to my radio (other car, drop out at potholes) which was impossible to find, only a new cable solved it.

 

[Notthenow]

Could be any of that right now. Electronics are not my strong suite so gonna have to gut it out and learn how to work through it. At least I have a code to stsrt with, P0643.

 

[Notthenow]

As an up date for someone some day looking for info and wondering what ended up happening. I clean the SBJ corrosion that was fairly mild off the terminals. None of it was at the fuel gauge connections. Then I put a new Delphi sender on the passenger side and a new Carter full unit on the driver side. Gauge is working steady and accurate with no diving to E. I am running lean as the long term fuel trims ate and have been over 10%. I am going to check the fuel pressure. Although my scanner says pressure is normal, I have a hunch the electronic regulator is inaccurate. Has anyone seen this?

 

[Notthenow]

Changed presure regulator and maf because I already had then. Reg was zero change. Maf brought added fuel down about 2%. Had the parts so figured why not. I know I hate to be a parts changer, but I had them and can't return.