I have a 2001 Silverado Z71LT that has some serious issues with a gas gauge. It doesn't work most of the time, but seems to work better when it's below 1/4 of a tank. Sometimes when it's full, the needle will swing up to full and then immediately after fall back to below empty and the "Low Fuel" indicator comes on. My wife's grandpa has an 01 Silverado that has the exact same problem.

Is this a common problem? How do I fix it without taking it to the dealership and dropping a couple hundred? Any ideas?

 

Either way, you are going to be spending a couple hundred, most likely. It sounds like the fuel sender which is part of the fuel pump. You should replace your fuel pump. Pretty common on these trucks. A price tag of about $230 for a new pump.

You can change this out yourself if you have basic mechanic skills.

You can one of two things to get the pump out:

1. Remove the metal straps that hold the tank on (4 straps I believe)

or

2. (I've done this) Get a buddy or two and unbolt the bed (6-8 bolts) and pick it up and slide it back to gain access to the top of the tank.

Moving the bed was easier for me because I did not have to worry about draining the tank and working on my back.

I can give you more detailed instructions if you want.

 

If you do not want to replace the pump, you can just replace the fuel level sensor. They are around $100.00 or so from the dealer. I would consider replacing the pump assembly (which will come with a new fuel level sensor) if you have a ton of miles on it, just to save you the hassle of having to drop the tank again to replace the pump due to failure. Also, I believe the new GM pumps have a different connector and require a new connector to be spliced in (included with pump).

Also, there is an easier way of draining the tank. Locate the fuel pump relay in the underhood fuse block. Disconnect the fuel line at the fuel filter, run a hose from the tank side of the line into a gas can, and have a few gas cans set aside. Next to the relay will be a very small rectangular shaped hole. Stick a wire with a terminal that fits in there. Take the other end and hook it to the battery positive on the battery. The fuel pump will turn on and allow the gas to drain. When the gas can fills, disconnect the above mentioned wire. Move the hose to another tank and hook the wire back up. Repeat as necessary.

 

Just so we're clear on this... I'm not having any mechanical problems. What you guys are saying is that inside the fuel pump assembly, the fuel sender isn't sending the right electronic signal causing the gauge needle to suddenly drop to below empty and the idiot light come on even if I have a full tank and the pump is actually sending fuel to the engine just fine. Am I correct?

I can replace the fuel pump no problem, I just want to know for sure if that's the problem. If I drop a couple hundred on a new fuel pump and that's not the problem, I'll have serious issues with the wifey.

BTW - I have 99K miles on it.

 

well fuel pump is not broken so why would you replace it ? I'd just keep it full or close to full all the time , if this is your daily driver you pretty much know when it is time to gas up.

 

Newt - you got it right - the sending unit is bad in the tank. Common problem on this timeframe GM vehicle. I have a 2000 Pontiac Montanna that I'm waiting for warmer weather to do the same thing.

Mr. Dummas - Thanks for the tip on draining the tank. I never like dropping a tank and sloshing gasoling on me!

 

LouB, I don't plan on replacing it until it goes out. If it were affecting how the it ran, I'd change it, but as of now, probably not.

Bad thing is, it's not a daily driver. My wife stays home and I drive her car to work due to gas mileage. She keeps the pickup, and many days, doesn't even pull outta the driveway, so most of the time, I really don't know how much gas is in it. Thanks for all the input folks.

 

I have an 01 chevy silverado z71 also, same problem. its been that way for about 1 year. when full, gauge will drop to empty with the idiot light comes on. Just annoying.
Use to it with the truck, been nothing but problems since new, same as with everyone I know that has one. engine knock, called cold start. the list goes on and on.

Bed take off is probably easiest way to change this though.
then you can work from the top down.

 

Just a reminder that the fuel level sensor is a serviceable item, meaning you do not have to replace the pump, just the fuel level sensor. It is your choice wether or not to replace the pump assembly.

 

a good thing might be is to have the fuel pressure checked before you start, if its anywhere low, might want to change it since you are already in the tank. might be a little more $$ now, but save time down the road.

 

the fuel level sensor should do the trick...I own a 2000 tahoe and did that one (had to remove the tank tho ) as well as a few others. i think replacing the fuel module (pump, sender, etc) is overkill...but i tend to be conservative.

GM also has a released a fuel tank additive that supposedly cleans the contact area of the sender (the sulpher in the fuel fouls the resistive strip on the rheostat) and may fix this problem. I've not tried it, so no opinion on effectiveness.