trunk question/ fuel gauge

[bungea]

I notice when i hit my key fob, my trunk opens but doesn't pop up. Its like it only unlocks it. When i had my Bonneville, when i hit the button it would spring it wide open. I have to manually lift it up and is hard initially but when u get it half way up its easy to continue lifting.

Is this the way its suppose to be? The vehicle is a 97 Pontiac Grand Prix 4dr gt sedan.

I also noticed that my fuel gauge is not always correct. It will read full when its suppose to then can go down to half full and really have like 14gallons left in it. It will go up and down then with around 5 or 6 gallons left in the vehicle it will read empty and put on the low fuel light. Can anyone recommend a fix, or is my sensor in the tank screwed up?

[olopezm]

The trunk thing is perfectly normal, don't worry about it.

On the fuel level the level sending unit is either dirty or bad, you can try cleaning it with some acetone and see if it works, with time some sulphur deposits build up at the resistor causing it to give a bad reading. Your model might or might not have the fuel pump access in the trunk compartment, lift the carpet by the backseat and you should see a cover, in case you don't then the only way will be lowering the tank.

Best regards,

Oscar.

[BNaylor]

Originally Posted by olopezm

Your model might or might not have the fuel pump access in the trunk compartment

The '97 models do have the FP access cover in the trunk. All '97-'03. Now '04 and up do not which is sad.

[olopezm]

It's good to know that Bob, I remember reading somewhere that there were two versions of 97 GP, one with the trunk access door and one without it.

[bungea]

where is the spot located i moved the carpets around and didn't see any wire besides the wire that connects to the trunk

[BNaylor]

Originally Posted by bungea

where is the spot located i moved the carpets around and didn't see any wire besides the wire that connects to the trunk

Did you pull the carpet material directly behind the rear passenger seat in the trunk? You won't see any wiring since it is all underneath above the gas tank.

My '97 GTP has it and it was mid-year production in 1997.

[rubberman]

Last summer my gas guage went out and i bought a used pump and took off the gas level sensor and replaced mine. I dont think you can just buy the sensor itself. When i pulled the pump i sat in the back seats and pulled out the pump. basically straddled the pull down console. I couldnt get the fuel level just right so i left it alone. it shows full when its full but when it gets to a 1.4 tank there is still 7 gallons left or so.

[BNaylor]

Originally Posted by rubberman

I dont think you can just buy the sensor itself.

The fuel level sending unit (new) is available as a separate part from the complete fuel pump assembly. Around $80. And we have a AC Delco parts source that gets them for us. Also, the stealership has them but at full markup.

Also, when installing the level sending unit it needs to be calibrated by adjusting the float arm and checking resistance over the complete swing with a multimeter. Or the actual fuel level versus what you get on the fuel gauge will be in error.

[rubberman]

how do you adjust the float? bend the arm?

[BNaylor]

Originally Posted by rubberman

how do you adjust the float? bend the arm?

Thats correct but still good to put a meter on it and see if the resistance range is correct. Some people do it by trial and error but it calls for removing the fuel pump pod assembly again. Good luck!

[rkvons]

As a first step, you might want to try running Chevron Techron Fuel system cleaner through it for two tank fulls (Two applications). This can clean the surface area where the level sensor is rubbing. I've had good luck in my wife's van when she puts lousy fuel in it and it reads full until half a tank.

[BNaylor]

Originally Posted by rkvons

As a first step, you might want to try running Chevron Techron Fuel system cleaner through it for two tank fulls (Two applications).

Good suggestion but you'll still probably get total failure sooner or later. Chevron with Techron is the only gasoline I ever use and still had to replace the one in my GTP and Buick Regal.

[alberta bob]

tried to improve on the ground wire no good finally removed fuel pump,found that the sending unit was pooched ,the reostat was loose on the float arm. replaced everything .was fairly easy take out the back seats ,couple of bolts ,remove pump cover 3/8 socket, remove the dirt around the pump hold down ring , remove gas lines (bleed off pressure first) undo wire harnesses remove ring and presto remove pump be carefull of the gas in the cup when twisting lifting turning to remove got one at the wreckers for 40.00

[Stealthee]

Originally Posted by BNaylor

The '97 models do have the FP access cover in the trunk. All '97-'03. Now '04 and up do not which is sad.

I'm actually fairly certain when I was in my trunk I saw an access panel for the fuel pump on my 07.