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.

Where does the fuel gauge come from on a Duramax?

I was in the process of installing an aftermarket gauge when I came across a wiring diagram of the fuel system on the internet (alldata). There are two wires coming from the ecm that work the fuel gauge so I took apart the fuse box to check if I seen anything obvious. It seemed as though all the wires were where they were supposed to be.

What is the Dorman number on the fuel gauge?

Today I replaced the electrical connector for the fuel sending unit at the rear tank and it solved the problem. The Dorman part number is 645-668. I hope this information can be helpful to those dealing with this annoying gauge issue.

Why is my fuel gauge not working on my Chevy?

By the way this is a 2004 chevy cab and chassis w/dual tanks. This is a list of what steps I took. Checked fuses cause I was getting no voltage to the sending unit. Went ahead and changed front tank sending unit ($125) still not working. So next was my biggest mistake and took it to the dealer.

How big is the fuel tank on a Chevy 3500?

Click to expand… 2019 3500 pickups have 36 gal tanks. I was just reading the new GM TECHLINK newsletter. It has an article concerning the 15-19 trucks with dual tanks. Has to do with dirt on top of the rear tank blocking the tank vent fitting.

Where does fuel go in a Duramax 3500HD?

I just got a 2015 HD3500 cab Chassis and while driving it yesterday with the fuel gage showing a quarter of a tank the low fuel light came one and the gage dropped to empty. Also the check engine light came on. I put fuel in the rear tank and then today put fuel in the front tank but was able to get just a little in.

How big is the front and rear fuel tanks?

Front tank is 23.5 gals. and the rear is 40. You will find that the fuel quantity gauge reads both tanks by an algorithm. When mine shows 1/8 remaining, I filled the front first and it took 10.7 gals. The rear took 34 gals.

Can a Chevy 3500HD run with a full tank?

Both tanks fulled, go down the road for 150 or so miles. get two notches on fuel gage below a half tank marking, and the engine shuts down with a full tank in the rear and nothing in the front. Rear tank doesn’t supply the front as it’s always full.

What kind of fuel pump does Chevy 3500HD have?

THe rear tank has only a two conductor wire connector going to it which is prob the sensor circuit only, and that rear tank does seem to feed thru a remote frame rail rmounted pump to supply the fwd tank. That fwd tank has a 4 wire connector I assume to power both the in tank fuel pump/sending unit combo.

Is the gas pump the same on the 3500?

For the side by side (L+R) tanks for the 3500, there is a porportional valve shown in the harness shared by both tanks. Both tank sending units/pumps seem to be the same PN. I have to suspect the selector or rear pump.

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.

Where is the gas gauge located on a Chevy truck?

The gas gauge, often located in the instrument cluster, consists of two small coils spaced 90 degrees apart with an armature and a needle placed at the intersection of the two coils. A dampener is also located on the armature to prevent excessive needle movement on rough roads.

Why does my gas gauge read high when the tank is full?

A functioning sending unit will have a high resistance when the tank is full and a low resistance when the tank is empty. If the gauge reads higher than it should, make sure the wire attached to the electrical terminal on the tank sending unit is making a good ground connection.

Why are my fuel gauges not working on my Chevy Silverado?

In fact, this is,unfortunately, a common problem among most GM vehicles built from 2003-2006 – various gauges in the instrument clusters of these cars and trucks tend to fail as the mileage starts to get into the “high” zone. This problem is caused by defective drive motors that were used on the circuit boards of these instrument clusters.

Where is the fuel level sensor on a Silverado?

If you were to send a tiny camera deep inside your fuel tank, you would find your fuel pump and fuel sending unit, swimming in fuel and quietly doing the jobs their names would suggest. Embedded among this happy apparatus, you would also find a fuel level sensor, which, also, would be doing the job its name suggests.

What to do if your gas gauge fails to move?

If the float is OK and the float arm seems to be swinging freely through its full range, replace the tank unit. Ground the gas tank terminal post of the tank sending unit using a jumper wire. If the dash gauge now reeds empty, the gas tank unit is defective. If the dash gauge needle fails t move, the dash gauge is defective.

What kind of cab does Chevy Silverado 3500 have?

BUILD ON A STRONG FOUNDATION. The Silverado 3500HD Chassis Cab features frame rails made of high-strength steel, utilizing nine cross members for rigid lateral support, and can be upfitted† to perform a range of tasks, including towing heavy loads, hauling large equipment and more. A wide variety of upfit options are available on this commercial…

Is the Silverado 3500 HD a work truck?

The All-New Silverado 3500 HD Chassis Cab is stronger and more capable than ever, and it’s ready to help you tackle even the most demanding jobs. It also has a strong foundation for your upfit† needs and offers technology to keep you connected from jobsite to jobsite. This all-new work truck offers the things you need to do it all.

Where is the dual tank balance module located?

This module is located by the front (main) lift pump. Slightly toward the rear of vehicle along the frame rail. On top of this module is a fuel pump balance relay, it turns the rear pump on as needed to transfer fuel. At the module, you have a harness with 6 wires. Unplug it and check the following with a digital volt/ohm meter

Where is the fuel pump on a Chevy 3500HD?

Raised the dump body and it was right there behind the forward fuel tank mounted on the frame rail. 15 minutes later, I gave the truck a start and that new pump gurgled into life emptying the rear tank into the forward tank and raising my fuel level. Yippee. I’m so happy I fixed this fuel curse I’ve been shouldering for a few months.

Why does my gas pump keep clicking off?

Every time you try to put gas into the car, the gas pump nozzle either keeps clicking off when the tank is not full, or spills out of the car. I thought maybe the gas was coming out of the pump too fast, so I slowed it down, but it still did not help.

What causes a car to have trouble filling the gas tank?

Trouble filling gas tank, gas pump nozzle clicks off when the car is not full, or spills out of the car. What is causing this? A bad gas cap will cause the light to come on, of so replace the cap. The vent is not working if gas is coming back at you. Replace with new.

Why are there two gas tanks but no selector switch?

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. I tried installing a new sending unit in each tank, but that didn’t solve the issue.

What kind of engine does a 2003 GMC ZF have?

Fuel induction: Sequential Fuel Injection (coil-near-plug) SAE Horsepower (hp / kw @ rpm): 225 (LQR) or 325 (LRW) / 168 (LQR) or 242 (LRW) @ 3600 (LQR) / 4000 (LRW) SAE Torque (lb-ft / Nm @ rpm): 350 (LQR) or 450 (LRW) / 475 (LQR) or 603 (LRW) @ 1200 (LQR) or 2800 (LRW) Transmission type: ZF S6-650 (M50) 6-speed manual

How does a Chevy truck’s dual fuel tanks operate?

Any malfunction in either of the fuel gauge circuits will disable the system and the fuel will not be transferred from the auxiliary fuel tank to the main fuel tank. Loading…

What happens when you turn off the relay on a gas tank?

Contacts in this switch close and send 12 volts to the fuel pump. The system will stay in this configuration until you turn the key off or the engine looses oil pressure. The 3 second operation of the fuel pump by the relay is to prime the fuel system, this makes the engine easier to start.

Where is the fuse on the fuel tank?

Fuse is in underhood fuse/relay center marked IGN E 10 AMP Terminal B- Light Blue wire, this is the signal wire from the secondary (rear) fuel tank, using an ohm meter, measure the resistance from a good chassis ground to this wire and should get a reading between 0 and 90 ohms, 0 is empty tank and 90 is full.

How many gallons of fuel is in the front tank?

Quick check with EFI Live and it thinks we have 14 gallons on board and no way to get to it. Oh and the rear tank holds 15 gallons. So a call to AAA RV, and 5 Gallon of fuel and we are back on the road using only the front tank. On the return trip home the pump did somewhat work on occasion a gallon or four here and there but not like it should.

How does the fuel balance pump work on a dual tank car?

—- On vehicles with dual tanks, the front tank is the main and the rear tank is the auxiliary. The main fuel balance pump supplies fuel to the fuel injection unit. The low pressure, about 32 kPa (7 psi) fuel balance pump is used only to transfer fuel from the auxiliary tank to the main tank in order to balance the fuel levels in both tanks.

Is it safe to remove a fuel tank?

A simple, step by step process for removing a fuel tank. A safer and effective fuel pump repair job begins here. Cleaning the fuel tank is an essential part of a complete fuel repair. Before installing a new fuel pump, it’s critical to properly clean the gas tank. Debris in your gas tank will damage your new fuel pump.

Where to buy parts for a Ford dual fuel tank?

EXPLAINED and where to buy parts! If playback doesn’t begin shortly, try restarting your device. Videos you watch may be added to the TV’s watch history and influence TV recommendations. To avoid this, cancel and sign in to YouTube on your computer. HEY!……

What kind of fuel tank does a Silverado 3500 have?

Some 2015-2018 Silverado and Sierra models and 2019 Silverado 2500/3500 and Sierra 2500/3500 models equipped with the 6.6L Duramax diesel engine (RPOs LML, L5P) and dual fuel tanks (23.5 gallon/89 liter front tank and 40 gallon/151 liter rear tank) (RPO N2N) may have poor fuel transfer or the rear fuel tank may have collapsed. (Fig. 13)

What kind of diesel does a Sierra 2500HD have?

2001 2500HD Sierra w/6.6L Duramax diesel. Sometimes, not often, once a month or so my truck at start up won’t fire, just turns over. I have to go under the hood and pump up my diesel fuel system – located on the passenger side of the engine.

Can a GMC Sierra run without a fuel pump?

Without gas your Sierra will not run at all. With that in mind, most of the symptoms of a bad fuel pump revolve around the vehicle stalling out or not running at all. In modern fuel injected vehicles, the fuel pump sits right in the fuel tank and “pushes” the gasoline to the fuel rail (s).

Why is my Duramax diesel engine not starting?

I have seen more leaks causing no starts, loss of prime and low fuel rail pressure codes from poor fitting aftermarket fuel filters use Delco only. Remember when dealing with power loss and fuel pressure issues the duramax has no in- tank or frame mount fuel pump pushing fuel to the engine.

Are there any issues with the Duramax fuel pump?

The new injectors available from us and others are updated and do not have the cracking issue. Fuel Filter Housing Oring Leaks – The Duramax fuel system does not have any sort of low pressure fuel pump pushing fuel to the engine from the tank. The injection pump sucks all the fuel from the tank.

How does the fuel pump transfer relay work?

Terminal D- Light Green wire, this wire controls the Fuel Pump Transfer Relay, with the ENGINE RUNNING and the front lift pump working, GROUND this wire, the Fuel Pump Transfer Relay should click and then you should be able to feel the rear pump working.

How many pins does a fuel pump relay have?

The fuel pump relay does often have 4 pins, and in this case, it is often easy. If your relay has more pins and not the same numbers mentioned here, you need to check a wiring diagram. Lift it and check under it for the numbers 30, 85, 86, and 87. If you locate these numbers, you can put the fuel pump relay back.

How does rear tank transfer pump two tank system work?

There have been a few old threads about this, but since it happen to me a few weeks back I thought I would bring this back up for the next guy. For those of us with the two tank arrangement, there is a transfer pump that moves fuel from the rear tank into the front tank as the front tank drops level.

Where are the terminals on a dual tank balance module?

Terminal-B (Light Blue) on the module comes from the rear tank sender, terminal-C (Blue/White) is the front tank sender and terminal-F (Purple) is the output to the fuel gauge or PCM/VCM. Set the Vantage/MODIS to Waveform Viewer and check the signals on these three terminals.

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.

Why does my GMC Sierra 1500 not work?

While there are a variety of reasons your GMC Sierra 1500 air conditioning won’t work, the most common 3 are a refrigerant leak, an electrical climate control issue, or a problem with the air conditioning compressor. What will be the outcome of an air conditioning system diagnosis?

Where is the ECM on a GMC Sierra 1500?

32 people found this helpful. It’s usually right next to the ECM, it will have a 60 pin connector to it, and is about 4X5 . 22 people found this helpful. Alright sweet thanks “tennisshoes”

When did the GM 6.2 diesel engine come out?

GM installed the 6.2 L diesel engine in light trucks and Sport Utility Vehicles between 1981 and 1993. The 6.2 L diesel is naturally aspirated, unlike the more recent 6.5 L turbo-charged diesel.

What is the wiring diagram for a Chevy truck?

Or you are a student, or perhaps even you that just need to know regarding Chevy Truck Dual Tank Fuel Wiring Diagram. Chevy S10 Fuel Gauge Wiring Diagram.

What was the name of the 1983 GMC light duty truck?

ST-386-83 1983 CHEVROLET GMC LIGHT DUTY TRUCK CK ST P & G-VAN WIRING MANUAL WIRING DIAGRAMS 1 ELECTRICAL CIRCUIT IDENTIFICATION FOR WIRING DIAGRAMS Circu it Number Circuit Color Circuit Name 2 Red Feed, Battery – Unfused 3 Pink Feed, Ign. Sw.

Why are there two gas tanks in my GMC 3500?