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Hi,
I recently had my fuel pump assembly replaced, and after filling up gas a couple of times I realized that the fuel gauge indicator is off by a few bars. It shows as if more gas is available than there actually is. E.g. after filling up a full tank, the indicator bars showed a full tank even after driving 100 miles. After about 100 miles it starts to go down correctly. But it's supposed to start going down after just about 20 miles or so. Luckily I haven't hit the other problem, where even if it says I have a few bars remaining, I might actually be out of gas!
I'm thinking it should just be some calibration issue with the new fuel pump assembly. Is there an easy way to calibrate those bars?
The car is a 2007 Civic EX.
Thanks,
CF

 
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what kind of part was used?
the float assembly could have been tweaked when it was installed

 
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I used a Delphi FG1044 fuel assembly.
Apart from tweaking the float, is there any other way to re-calibrate the gauge?

 
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I had a problem like this with my old one and I couldnt find the solution. I wonder if someone finds a solution for it.

 
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I finally fixed the problem, but it wasn't easy.
The short answer is that I had to adjust the float assembly manually (bending it using pliers) to get it to just the right level.

Based on what I could find on the internet, the fuel gauge display varies with the resistance value measured from the fuel pump assembly, and the resistance varies with the position of the float assembly. There are different youtube videos showing you how to measure the resistance using a multi-meter, and how the resistance varies as you move the float assembly up and down. I liked this one in particular (Note the readings he mentions are not for Civic):

Of course, with this generation of Civic, it's a real pain to get to the fuel pump assembly, you have to remove the back seat. Here's a great video showing you how to do it for the 2007 Civic:

Once I removed the fuel pump assembly, I measured the full tank reading (20 ohms) and the empty tank (782 ohms). These numbers are important and I couldn't find them anywhere. My tank was not quite empty when I did this, and I should have been at about 2 bars on the fuel gauge. I found out that 2 bars (+ warning light) corresponded to 698 ohms. Outside of the tank, the fuel pump assembly worked fine. But in the tank, the float would not go down far enough. and I was measuring about 450 ohms. That's why I was reading about 4 or 5 bars extra. I had to bend the float to just the right amount so that when it went back in, it read 698 ohms (which is what I wanted it to read). So now the fuel gauge went down to 2 bars + orange warning light. Perfect, that's what I wanted. Next, I went to the gas station and filled a full tank. Thank goodness, the display lit up all the way! So no more adjustments were needed. Problem solved.

Hope that helps others.