97 riv fuel gauge problem

[mickel777]

I am hoping there is a simple fix for my fuel gauge problem on my 97 riv. When full gauge reads full, with 1/2 a tank, gauge reads 1/2 all good so far. below 1/2 my gauge reverses so with a 1/4 tank of gas left it reads 3/4 and when on fumes it reads full. So, my queston is: has anyone had this and found a fix without going in the tank, ie, some kind of additive that may clean the sending unit without requiring a total replacement. Also, isn't the fuel pump and the sending unit on part or can they be replaced sepately? Thanks in advance for your input and experience!

[HotZ28]

This does sound like the sending unit (level sensor) took a dump! (No easy simple additive fix here)! You can purchase the complete unit with the fuel pump and sending unit as shown, (not cheap) or you can purchase the sending unit separately for about 120 bucks. ACDELCO Part # SK1000 {#25314202} SENSOR KIT,FUEL LVL.

I suggest replacing the complete unit. Notice the VIN (1) & VIN (K) are different part numbers!

1997 BUICK RIVIERA 3.8L 231cid V6 MFI (K) : Fuel/Air : Fuel Pump
ACDELCO Part # MU33 {replaces 25166642 #25166642}
MODULE,F/TNK F/PMP(SENDER & PUMP) $281.79

1997 BUICK RIVIERA 3.8L 231cid V6 MFI Supercharged (1) : Fuel/Air : Fuel Pump ACDELCO Part # MU35 {#25166648} MODULE,F/TNK F/PMP(SENDER & PUMP) SEAL-INCLS SENDER,PUMP & SEAL
$400.79




Courtesy of: Rockauto.com

[mickel777]

Thanks for the input, Well, I took out the pump/sending unit, which wasn't to bad with access from the trunk. The reostast was basically loose and not fixable. I spent the money and replaced both(one unit) for 300 plus tax. Works great! Still smarting from the cash outlay, but I wanted the gauge working and now it does.