My 1998 Civic-EX: After filling up the tank, parked/running on even ground, won't show tank as FULL... it shows as about 3/4-4/5 FULL. Pulled the back seat, removed wiring harness, jumpered across sending unit wires and watched as Gauge rose to FULL. AHAH! So I pulled the Sending Unit/Float Assembly, raising the float manually to see if the Fuel Gauge moved to FULL (it did), and I noted that there was a little fuel in the Float so I figured it was "water logged" with fuel. I replaced the SendingUnit/Float Assembly, testing the new float to make sure the gauge read Full when manually moving it upward. It did. I reassembled the sending unit Assembly with a NEW ONE and even took some sand-paper to the terminal ends that plug into the SendingUnit Assembly to make sure I had a good connection. Even after filling up the tank, the Fuel Gauge still doesn't show as FULL. It's not as bad as it once was, but I am back to using the Trip Odometer - knowing that I should probably fill up around 300mi. I hate "Trial & Error", ie- admitting that I may have made a mistake, but the float DID have some fuel in it. The connection at the Fuel Gauge is the only thing left (besides trying to track down the entire circuit line to see if it has insulation cracked off, slightly shorting out the line). Any suggestions? (before I begin taking the fuel-gauge assembly out of the dash) Thanks!
FUEL GUAGE IS WRONG: Won't Show as FULL w/tank filled up. on 1998 Honda Civic
have gauge tested and if its good most likely the fuel sending unit in fuel tank
It seems like the gauge is working properly, as you said that you moved the new float and observed the gauge go to full. I suspect the new float wire may be bent. I would compare it to the old and maybe even a new from Honda. I have also seen the sending unit not installed correctly and hitting the tank or the baffle.
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check the fuel gauge in the dash