Why does my gas gauge not work on my GMC Truck?

Trucks of that “era” had a problem with the gauge cluster that would make the fuel gauge (and/or other gauges) not work. Quick google search says that onboard computer monitors the fuel level in both tanks and averages the fuel remaining to show on your gauge.

What’s the problem with the twitching fuel gauge?

I’ve the same problem happening on the ‘burban. 1999 that was just purchased and the fuel gauge looks as though it’s had way way WAY too much coffee. When we actually first got in it the fuel was very low and the gauge actually started low then slowly rose up to full after a few slow minutes, kicked back down and then was all over the map.

Why are there two gas tanks in my GMC 3500?

Gmc Two Gas Tanks Why No Selector Switch. Hows It Work? My 02 GMC 3500 Dump fuel gauge is broken. The gas gauge shows E and the fuel message board says low fuel. It has two gas tanks but no selector switch, and it seems to pull gas from both sending units at the same time, while keeping track of the total fuel amount.

How does a fuel pump work on a gas gauge?

The fuel pump module includes the fuel sending unit, used by the gas gauge to detect and display fuel level. https://www.flickr.com/photos/3ndymion/33556245572. The gas gauge is a relatively simple circuit, but its simplicity means each component is essential to its function.

What do I do if my gas gauge is not working?

In most cases, to gain access to the fuel tank sending unit mount / fuel pump mounting hole, you’ll need to drop the gas tank down. Be sure to do this when there is either minimal gas in the vehicle, or it’s been siphoned out.

What does the gas gauge read when the tank is empty?

Most older sending units are a “0-30” or “0-60” ohm sending unit, meaning that when the tank is at empty, the resistance will read 0ohms, where at full, it will read 30, or 60ohms. To test this, simply put your mutl-meter to ohms (resistance) setting, and touch off one probe to the sending terminal, and the other probe to ground.

How does the resistance of a gas gauge change?

The fuel float contacts run on a potentiometer, or variable resistor, whose resistance changes depending on float level, effecting a change in output voltage. Some systems are wired so that high fuel level contacts the low-resistance section, gradually increasing resistance as fuel level drops.

What’s the best way to disconnect a fuel line?

Very well made (METAL not plastic) disconnect tool. It made easy work of 16+ year old fittings on a 2001 Duramax fuel tank. Works very well. Just spray some WD40 itno the fitting first to loosen any grit or rust. Excellent tool. Clean as best the connection as best including lube. And watch face cause gas will come out. Likely made in Tiwan.

How does the gas tank work in a GMC?

Quick google search says that onboard computer monitors the fuel level in both tanks and averages the fuel remaining to show on your gauge. The primary fuel pump is in the front tank. When the level in the front tank drops, it sends a signal via a fuel pump relay to trigger the rear fuel pump to send fuel to the front tank.

Where does OTC 6511 fuel line disconnect tool work?

The tool is designed to access the center port on the GM fuel tank sending unit. For 3/8″ and 1/2″ applications. Will also service 2001 – current 3/4- and 1-ton trucks with the Duramax diesel engines. “I’M PROUD OF THE OTC BRAND.

Why is my fuel tank collapsing on my GMC Sierra?

I’m also having this problem with my 2000 GMC Sierra SL c2500 5.7. It creates a vacuum and collapses the fuel tank. Im on my third fuel tank but didn’t realize at first a vacuum was crushing it. Any ideas? It seems the more I read, the more possibilities that could cause it but its getting expensive with the tanks and pumps.

Where does the fuel line go in a GM Truck?

The fuel lines go up over the trans to the engine. The vent line continues into the engine compartment along with the rear brake line. The vent line goes to vapor canister mounted near the radiator on the drivers side.

How is fuel venting done on a GM Truck?

The gas cap is sealed, the venting is done through the line Tim mentioned. There are three lines to the tank. 3/8, 5/16, and 1/4 inch. 3/8 is the supply line. Fuel is pumped through this line from the tank to the fuel metering body. (No TBI on a 97 Vortec). The 5/16 returns excess fuel from the metering body back to the tank.

Where does the 5 / 16 fuel line go?

The 5/16 returns excess fuel from the metering body back to the tank. The 1/4 line is the vent line. All three lines come up the drivers side frame rail. The fuel lines go up over the trans to the engine.

How to fix fuel gauge on GMC Duramax?

Cut the tie and pull the wires from the harness and inspect for cuts and wear. The sharp corner of the FICM bracket where it is tied down to, cuts into the wires. Repair and insulate the harness with a short piece of heater hose.

What to do if your fuel gauge is bad?

Fuel gauge troubleshooting begins with isolating the problem either to the gauge, sending unit, fuse or wiring. The most common gauge problems are either a bad ground at the tank, or a sender problem. As with any electrical troubleshooting, it is best to check the fuse and all wiring connections are clean, tight and free of corrosion.

Why does my gas gauge not work on my GMC Truck?