04 Rendezvous fuel gage problem

[Rookie#1]

I read on a buick forum many folks are having fuel gage problems on their early 2000 rendezvous. I'm in the boat with them. Full tank fuel,
gage reads ok. From there to LO FUEL reading gage is very erratic. Removed fuel pump, put a digital meter across the sending unit and the reading followed the float position just fine. Connected the fuel pump to the car and varied the float and the fuel gage read perfect. Added info this is the second generation fuel pump for the 04 Rendezvous. Where there are so many people having this problem could alcohol in the gas be causing this problem. My, fuel pump works just fine,

[Tech II]

If I am dropping that fuel tank, I am having a new fuel sender available, to install on the module.....

One other place to check, is the pass through connector through the floor, located just behind the driver's seat, underneath the vehicle.......those connections can get corroded...

[Rookie#1]

Tech2 the connector looks like new. Everything is very clean for a 04. Yes, I'm going to replace the fuel pump while I have it apart even tho the 04 only has 102,000 miles. Still wondering why the old sending unit works perfect out of the tank but not in the tank.Even the sending unit finger stock looks and connects as if they are new.

[bellaCuba]

How are you testing the arm (fuel level sensor)? Both in & out the tank the same method?

Yes, the Ethanol kills our engines. ..eats up the plastic parts in the system, & its hydroscopic, so it adds water to the system over time.
It's good to use a stabilizer from time to time.

[Rookie#1]

Thanks to both Tech@ and bellacuba for your replies. Bella I don't know what you mean in the tank. I have the fuel pump removed at this time no fuel i the tank. Other the erratic reading I was getting with fuel in the tank before removal, the only testing I have done since rmoving the fuel pump and sensor was meter across the sensor with digital meter and connecting the pump to the car outside of the tank. Digital meter responded accurate with variation of the float and the car fuel level indicator responded accurately when I varied the sensor. The new OEM fuel pump has a new style sensor. Instead of plastic it has a ceramic base. Don't know if the variable reostate has been replaced with gold finger stock which I seen other pump manuf. have done. Pump should arrive by the 14th of July. Will post again at that time on results.

[bellaCuba]

Originally Posted by Rookie#1

I'm going to replace the fuel pump while I have it apart. ..... Still wondering why the old sending unit works perfect out of the tank but not in the tank.

I guess the way you worded the abov portion of your message, it threw me off. I figured you were testing the operation of the sender.


The reason why I was asking. If the operation of the sender it fine out of the tank... or with the meter like you stated in your last post, your issue could be with the connections, wiring, or the gauge itself.

Some gauges have the stepper motor setup in the cluster. These things will also go bad. Sometimes with just playing with the ignition key On & Off (no crank), you can tell. The needles typically go up and settle... not the case when one of the motors goes bad. It jumps around, makes noise, never consistant where it settles are a few of the symptoms.

Just wondering is all.

[Rookie#1]

Well. I'm back with a followup. While I had the gas tank out (105,000 miles) I replaced the fuel pump and sending unit. Didn't think that was the problem but what the heck. I was right, it didn't fix it. Removed the cluster panel and replaced the stepping motor on the back of the fuel gage and bingo. I now have a functional gas gage. For a good procedure on removal of the cluster gage google HOW TO REMOVE RENDEZVOUS INSTRUMENT CLUSTER. Select the Buick forum link. Youtube has a good procedure on replacing the stepping motor on the cluster panel. Geed luck all.