Fuel Gauge

The fuel pump assembly has a arm that goes up and down with a float attached, sometimes this float is dislodged upon reinstalling the new pump and either comes off the arm or is tangled in the wires or is bound in some way. remove the assembly and fish out the float and reattach it back on untangle it, make sure it is being installed in correct position or if this is too much work or money to fork out, if the float is still attached it will actually cause the needle to go down when full instead up so when as you get closer to empty the needle will go up to almost the 1/4 mark so when its close to 1/4 stop and get gas and watch the needle go down and make a note how far/miles you made it on a tank of gas until it get almost the quarter mark and when you make it to that point adjust it to always have a little gas in the tank. if this is the case the needle is restricted to only up to the 1/4 mark and work in reverse.

Float could of been damaged during removal and be full of fuel and not working as intended.

i also connected my removed fuel pump and moved the float by hand up and down with key on but needle does not move

If its still out you could use a meter to check if the wire is getting current out to the gauge if it is then if the gauge worked before I would not think the gauge is at fault but could be, I think there is a small computer board that takes the signal from the float arm and send it to the gauge. If it is not sending current then it needs replaced and or the arm mechanism. Did you change out the entire assemble or the pump only? may try some contact cleaner on board (electrical parts cleaner), oil could gotten on it. Did the gauge work fine before. Check the fuses just in case its that simple.

Pump is a complete new assembly including sending unit. my fuel gauge was constantly worked no matter key on or off. i'm suspecting whether sending unit getting power in order to work the gauge any idea

Hate to say it but it may be faulty unit unless there is a pulled wire, may have a break inside the insulation somewhere, Got to be a reason why the unit is not able to tell the gauge where it the fuel level is. either the new faulty unit or when lowering the tank to get to the sending unit it pulled some wires.

Some mechanics put the wrong fuel strainer on the end of the fuel pump which interferes with the float completing its path. The fuel guage will stop at 1/8th and the warning lite will not come on. This is obvious when taking the fuel module out and looking at the float sitting on top of the strainer. Put the old (original) strainer on the fuel pump and it will work correctly unless there is another problem. I did this and every thing works great..