OK I just changed the fuel pump assembly so it has a new fuel sending unit and float. When I took out the old fuel pump assy the gauge read 1/2 (which is really 1/4), with the new fuel pump assy it reads just above Empty with the same amount of fuel. To do a little troubleshooting I went to the gas station and filled it up. When the tank is topped off it reads between 3/4 and Full. It used to read way past full before. When I cornered hard I could get it to read Full. So I know the float is not stuck. The fuel pump assy is made by Carter (a division of Federal Mongul) and I bought it from pep boys.

So why is the gauge off?

I looked at the new and old fuel pump assy and did notice that the potentiometer were designed different between OE and Aftermarket. Could the company who made this got the resistance wrong with full and empty?

Any easy way to fix this? Possiblly adding an inline resistor? or could I just reposition the fuel gauge needle?

What are you guyes thoughts?

 

Year of vehicle?

Why not add basic info about your car to your "Signature" - year, model, engine, trans and any major mods.

 

Oh yeah sorry. Its a 1996 3.8 camaro convertable. The pump assy I bought said it was for a 96-97 3.8 camaro

 

Shoebox has a chart of sender resistance vs. fuel level.

http://shbox.com/1/4th_gen_tech2.html#fuel_gauge

Did you verify that the new float arm put the float at the same level as the stocker?

 

Thanks for the info. I got something like 50 to 60 ohms on a full tank, so I pulled out the pump assy and exchanged it with a new one. Good thing I was smart enough to cut a "trap door" or that would have really sucked! The old fuel gauge when full would read about the equalivent to a quarter tank past full. The new one reads just past full... so I guess this one is being more accurate. The old one I would be on full for a half tank, now it drops off full right away... much better!

 

I had the exact same thing happen. It seems more accurate now, but looks like the fuel is being used faster. It doesn't stay on over full for so long a time, but yesterday when I filled up with the gauge at the half-way mark it took 7.5 gallons. Can't remember if I compared resistances or not - I don't think I did.