2004 Chrysler Pacifica Fluctuating Fuel Gauge Indicator

To check the fuel pressure on a 2004 Chrysler Pacifica with a 3.5L engine, you will need to locate the fuel pressure test port. This is a small, threaded port that is usually located on the fuel rail. The fuel rail is a metal tube that runs along the top of the engine and supplies fuel to the fuel injectors.
To check the fuel pressure with a fuel pressure gauge, follow these steps:

1. Locate the fuel pressure test port on the fuel rail. It should be a small, circular port with threads on the inside.
2. Attach the fuel pressure gauge to the test port. The gauge will have a hose with a fitting on the end that screws into the test port.
3. Turn the ignition key to the "On" position but do not start the engine.
4. Observe the fuel pressure gauge. The needle should move to indicate the fuel pressure.
5. Compare the fuel pressure reading to the manufacturer's recommended fuel pressure specification for your engine. This information can usually be found in the owner's manual or by contacting the manufacturer.

Check fuse 4.

Chevrolet S-10 (1994-2004) fuses and relays

https://fuse-box.info > chevrolet > chevrolet-s-10-1994-...
1997 - Here you will find fuse box diagrams of Chevrolet S-10 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003 and 2004, get information about the ...


Wiring diagram for the fuel pump

https://www.google.com/search?q=1997+chevy+s10+fuel+pump+wiring+diagram&rlz=1C1QJDB_enCA643CA644&sxsrf=AOaemvIE_tX-Fl6Z8Z0iSxCsRVwqrIdvZA:1635212709552&source=lnms&tbm=isch&sa=X&ved=2ahUKEwjP8byF-ubzAhV2nWoFHeZQCyEQ_AUoAXoECAEQAw&biw=1920&bih=937&dpr=1

..

Calibrating a fuel gauge used to be a regular job in the repair workshop but since CAD and CAM became features in car factories it is rarely required.

One problem is the type of gauge used, with moving coil and moving iron types being largely superceded by a hot wire type.
A feature of this type of gauge, or more strictly indicator and not gauge, is during cold weather for instance, the indicated fuel volume after driving 20 miles or so and the cabin has thoroughly warmed, can be considerably more than when starting...

Calibrating the fuel level gauge, indicator (approximator) requires putting enough fuel in an empty tank for it to be exactly half full and then to remove the fuel gauge sender, transmitter or sensor and bend the float arm slightly, refit and repeat until the gauge shows half full...

Your float level is stuck or went bad. If you replaced the whole unit. You could have jammed it if not then it's a bad pump assembly

Fuel gauge drops to emptyChrysler Minivan

The fuel level indicating system is a magnetic type system, which consists of the sending unit located in the fuel tank, an anti-slosh module located on the back of the instrument cluster, and a fuel gauge located in the instrument cluster. The sending unit changes resistance according to the level of fuel in the fuel tank, which varies the current flow through the gauge.The pointer position varies proportionately to the current flow. In this system, the sending unit resistance is low (22 ohms) when the fuel level is low and high( 145 ohms) when the fuel level is high. The pointer of the magnetic gauge remains in position when the ignition is turned to the Off position. On some models, an anti-slosh module is used to dampen out fluctuating fuel signals from the sender. Some vehicles are equipped with a low fuel warning indicator. The anti-slosh module will also actuate the low fuel indicator when the fuel level in the tank reaches 1/16 to 1/8 full.


Do your other gauges/warning indicators work properly with the ignition on? If not, check for power at the fuse panel/fuses.

If they do then partially remove your cluster with connector still installed and check for voltage at cluster connector and gauge. Check continuity of cluster and gauge for ground.

Sometimes the anti-slosh module (if installed) goes bad in the Grand Marquis but not likely.

Sender troubleshooting:

1. Perform test with resistors as follows:

1. Disconnect wiring connector at sender unit, then connect resistor between gauge lead and a suitable ground.
2. Turn ignition switch to On position.
3. With 145 ohm resistor, the gauge pointer should contact the Full mark.
4. With 22 ohm resistor, the gauge pointer should contact the Empty mark.

1. Perform test with fuel sender of known quality as follows:

1. Turn ignition to Off position.
2. Disconnect wiring connector from sender and connect it to test sender.
3. Move float rod away from fuel filter against Full stop position. Wait approximately 30 seconds, then turn ignition switch to On position. The gauge should read on or above the Full mark.
4. Move float rod toward fuel filter against Empty stop position. Turn ignition switch to Off position. Wait approximately 30 seconds, then turn ignition switch to On position. The gauge should read on or below the Empty mark. If gauge works properly replace sender, which involves dropping fuel tank.
   

If the car is running fine, then that is a possibility. The mechanic should have cleared the code. If you ever have an issue that triggers the ECU, then that is stored in the memory, and will need to be cleared.

2007 Chrysler Pacifica having intermittent fuel gauge problems. Goes from normal to dead/ low fuel. Has full tank. Also, check engine light is on

The problem will get worse, to the point that it will leave you stranded, out of gas. The solution is simple but most dealers don't catch it. They try fuel pumps, computer updates, sensors and the problem persists. You can fix this problem yourself and without spending a nickel. Want to know how I know? I've owned two Pacifica's and both have done this. Here's why: The Pacifica has a very unique and poorly designed fuel storage system. It uses what is refered to as a saddle tank. This is so they can use the same tank in both the all wheel drive and the front wheel drive versions. If you look underneath you will see it actually looks like two tanks. The driver side is the fill side and the passenger side is the delivery side. There are actually two fuel pumps, a main pump (pumps gas to the engine) and a equalization pump (pumps fuel from the the fill side to the delivery side of the saddle tank. The problem that you are experiencing carries with it several symptoms; running out of gas when the tank is half full, the gas gauge dropping suddenly at half full, and the inability to pump more gas into the tank without shaking the car back and forth and/or pumping very slowly. This is because of the way the two sending units inside the tank send their signals to the gas gauge and the fact that only when the fill side of the tank is 100% full, can some of the gas flow over the top of the hump to the delivery side tank. You can replace pumps all day long and most likely still have the problem. So what's the fix? It's simple. Underneath the vehicle, inline with the emissions lines going to the gas tank, about middle of the vehicle, there is a small plastic air inlet filter about the size of 50 cent piece mounted to the floor of the vehicle. It is responsible for venting the tanks pressure, allowing fuel to flow into the delivery side tank. It get's full of dirt and debris. Replace it a cost of about $3.50 or just blow it out with compressed air. If you don't want to do it yourself, help those dealers out - point them in the right direction, or else they will be running in circles trying to fix the problem. NOTE: this is only a problem on Pacifica's, not other vehicles. More info on this issue here; http://www.dodgeboard.com/forums/index.php?threads/my-crazy-gas-gauge.6381/

OK, your fuel indicator is wired to a sending unit that is located inside the fuel tank. this assembly is part of the fuel pump assembly. the fuel indicator sending unit is housed in the same assembly as the fuel pump. The fuel indicator will not function properly if there is a bad ground or, if there is a fault within the sending unit. there is a floater device attached on this assembly and, it raises with the fuel level and lowers when the fuel level is low, sending resistance signals to the indicator gauge on your dash board. these signals can be disrupted if the ground is corroded or, if the sending unit is damaged. In most cases, replacing the sending unit will fix this issue. if the fuel indicator is stuck on the full mark, check the ground. if the fuel gauge is laying on empty all the time, replace the sending unit.