sticking fuel gauge sender

[Matt_S]

I've started to think that my fuel gauge sender is sticking. The reason is that if I'm stopped at a traffic light, the gauge will read a certain level. When I accelerate, that level will increase and stay there until I hit the brakes again, then it will drop and stay there until I accelerate again. This is strictly correlated to vehicle acceleration and deceleration, not engine RPM or vehicle speed.

Is there a cleaner or some fuel tank additive that can help me here? I saw the thread where someone had good luck with 3M fuel injector cleaner, but what are my other possibilities? I'd prefer not to drop the tank, but may do so if it's the only way.

Edit: Here is the link to the 3M web site with the product information, data sheet & MSDS.
3M web site

Here is the other thread I referred to:

3M Fuel System Cleaner Thread

[ June 16, 2004, 02:07 PM: Message edited by: Matt_S ]

 

[GSV]

Could it be that the float is in the rear of the gas tank and the acceleration momentarily raises the level of fuel in the back of the tank?

That link goes to a thread I started. The Subaru is still much better. Prior to using the 3M cleaner the guage would only read to about 3/4 Full and once you got much below half it dropped very quickly. You had to use the trip odometer.

Now the gauge goes to F and tracks well all the way down to E after about 400 miles.

The Nissan tracks better down to E but it still doesn't go all the way to F on every fill. I'm going to run another bottle in about a month and swap out the fuel filter.

I'll try to remember to update the other thread.

[ June 16, 2004, 04:30 PM: Message edited by: GSV ]

 

[Matt_S]

I'm used to seeing the gauge move somewhat on acceleration and deceleration, but it seems that now the needle is moving much more than it used to and will stick in a position that I know is either too high or too low until I either accelerate or brake again. So, basically, I'm almost sure it's sticking.

Does anyone have a line on where to get that 3M fuel system cleaner at retail? The one Napa I called doesn't carry it, but said they used to carry the three pack of that, the throttle body cleaner and the aerosol used for the actual injector/upper engine cleaning, which I don't want. The only thing I found online is a two pack of the tank additive and throttle plate cleaner, which is OK, but I'd prefer to walk into a store and just get the tank additive.

 

[jason07-1zzfe]

What car? In my car I can pull the sender in ~5min. Then you could do it manually.

 

[Matt_S]

It's a 2000 Monte Carlo SS.

 

[jason07-1zzfe]

Oh, you probably have to drop the tank don't you? Ok scratch that idea.

 

[Matt_S]

Exactly. That's why I'm trying the chemical route first.

 

[GSV]

Try http://www.napaonline.com if you cn't get it locally.

 

[Matt_S]

Just a follow up.

I wound up replacing the sender. It wasn't a bad job. There's an access panel underneath the carpeting in the trunk. (Fellow W-body owners take note of this). Once the panel is open, it's a matter of unclipping three fuel lines and two wire connections, undoing a hold-down ring and pulling the sending unit out. I got a used one through usedpartsfinder.com from a Junkyard in Flint. $75 plus shipping. The gauge is now working like it should.

The problem with the old one is that the metal contacts had lost their springiness. That, coupled with the fact that the pivot point of the float was loose, caused the erratic readings. I'm keeping the old sender so I can have a spare part just in case the fuel pump goes bad.