gbynum

2008 2WD SuperCrew Lariat;

Starting about a month ago, the fuel gauge tends to read high; it will occasionally drop to what I think is more nearly correct. It doesn't really fit just sticking; it will read higher frequently after being parked in my level garage than when I shut it off. This has the 30 gallon tank.

Shy of dropping the tank and replacing the sender (and probably fuel pump?) is there anything I can try? I'm old and no mechanic, so it'll be a shop job, I'm afraid.

Thanks!

needsmoarturbo

The fuel sender is just a potentiometer that varies how much voltage ends up reaching the fuel gauge I think... Unless you have a flex fuel truck, which in that case it has some signal that comes from the pcm and a different setup for the sender it calls it a "ac/dc converter" on the wiring diagram.

techrep

iTrader: (1)

You sure it's not a cluster issue. do a sweep test on the gauges.

gbynum

sure ... NEVER.

But the distance to empty display agrees roughly with the cluster gauge which leads me to the sender.

How do I perform a sweep test? Newer vehicles of at least both GM and Ford seem to do a full sweep on each engine start.

needsmoarturbo

from the service manual:Fuel Gauge

The instrument cluster receives the fuel level signal from the fuel level sensor, part of the fuel pump module. The fuel level sensor measures variable resistance in the fuel tank depending on the current fuel level. For vehicles equipped with flex-fuel, when the fuel level is low, resistance in the unit is low (7 ohms ± 2 ohms). When the fuel level is high, the resistance is high (138 ohms ± 4 ohms). For vehicles not equipped with flex-fuel, when the fuel level is low, the resistance in the unit is low (15 ohms ± 2 ohms). When the fuel level is high, the resistance is high (160 ohms ± 4 ohms).

The instrument cluster uses 4 different operating modes to calculate the fuel level:

• Anti-slosh (default mode)
• Key OFF fueling
• Key ON fueling
• Recovery

After a fuel fill up, the time for the fuel gauge to move from empty (E) to full (F) ranges from 2 seconds to 55 minutes depending on which operating mode the fuel gauge is in.

The default fuel gauge mode is called the anti-slosh mode. To prevent fuel gauge changes from fuel slosh (gauge instability due to changes in fuel sender readings caused by fuel moving around in the tank), the fuel gauge takes approximately 55 minutes to go from empty (E) to full (F).

The key OFF fueling mode (2 seconds to read empty [E] to full [F]) requires 3 conditions be met:

• The key must be in the OFF position throughout the entire refueling of the vehicle.
• At least 15% of the vehicle's fuel capacity must be added to the fuel tank.
• The instrument cluster must receive a valid key ON fuel sender reading within 1 second of the key being put into the RUN position. The key ON sample readings are considered valid if the fuel sender reading is between 15 ohms ± 2 ohms and 160 ohms ± 4 ohms.

If these conditions are not met, the fuel gauge stays in the anti-slosh mode, which results in a slow to read full (F) event.

The key ON fueling mode (approximately 90 seconds to read empty [E] to full [F]) requires 3 conditions be met:

• The transmission is in PARK (P) (automatic transmissions), or the parking brake is applied (manual transmissions).
• The key is in the RUN position.
• At least 15% of the vehicle's fuel capacity must be added to the fuel tank.

In key ON fueling mode, a 30-second timer activates after the transmission is put into the PARK (P) position or when the parking brake is applied. When the 30 second time has elapsed and at least 15% of the vehicle's fuel capacity has been added, the fuel gauge response time is 90 seconds to read from empty (E) to full (F). When the transmission is shifted out of PARK (P) or the parking brake is released, the fuel gauge strategy reverts to the anti-slosh mode. This mode prevents slow to read full events from happening if the customer refuels the vehicle with the key in the RUN position.

Recovery mode is incorporated into the instrument cluster strategy to recover from a missing fuel level input after a refueling event. Missing fuel level inputs result from intermittent opens in the fuel sender or its circuits. Recovery mode (empty [E] to full [F] approximately 20 minutes) is initiated when the following 2 conditions are met:

• The instrument cluster is in the anti-slosh (default) mode.
• The actual fuel level in the tank is greater than what is being displayed by the fuel gauge.

needsmoarturbo

PINPOINT TEST B: INCORRECT FUEL GAUGE INDICATION

Test Step Result / Action to Take


B1 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND INSTRUMENT CLUSTER SELF-TESTS

• Check for recorded instrument cluster DTCs from the continuous and on-demand self-tests.
• Are any DTCs recorded?

Yes
For DTC B1201, GO to B3 .

For DTC B1204, GO to B6 .

For all other DTCs, REFER to the Instrument Cluster Diagnostic Trouble Code (DTC) Index in this section.

No
GO to B2 .


B2 CARRY OUT THE INSTRUMENT CLUSTER OUTPUT STATE CONTROL USING THE SCAN TOOL

• Key in ON position.
• Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster Output State Control.
• Enter the instrument cluster output state control and select FUEL. Command the fuel gauge on then off and observe the fuel gauge.
• Does the fuel gauge start at E (empty) and move to F (full), and return to E (empty) when commanded on and off?

Yes
GO to B9 .

No
GO to B14 .


B3 CHECK THE FUEL PUMP MODULE FOR AN OPEN

• Disconnect: Fuel Pump Module Assembly C434 (Gasoline Engines).
• Disconnect: Fuel Pump Module Assembly C4329 (Flex-Fuel Engines).
• For gasoline engines, connect a fused (5A) jumper wire between the fuel pump module C434-2, circuit 29 (YE/WH), harness side and the fuel pump module C434-1, circuit 396 (BK/OG), harness side.
• For flex-fuel engines, connect a fused (5A) jumper wire between the fuel pump module C4329-5, circuit 29 (YE/WH), harness side and the fuel pump module C4329-1, circuit 396 (BK/OG), harness side.
• Key in ON position.
• Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster Self-Test.
• NOTE: It may be normal for DTC B1201 to be present when carrying out this test step and should be ignored.
• Clear the instrument cluster DTCs. Repeat the instrument cluster self-test.
• Is DTC B1204 retrieved?

Yes
REMOVE the jumper wire.

For gasoline engines, GO to B12 .

For flex-fuel engines, GO to B11 .

No
REMOVE the jumper wire. GO to B4 .


B4 CHECK CIRCUITS 29 (YE/WH) AND 396 (BK/OG) FOR A SHORT TO VOLTAGE

• Key in OFF position.
• Disconnect: Instrument Cluster C220a.
• Key in ON position.
• Measure the voltage between the instrument cluster C220a-27, circuit 29 (YE/WH), harness side and ground; and between the instrument cluster C220a-28, circuit 396 (BK/OG), harness side and ground.
• Is any voltage present?

Yes
REPAIR the circuit in question. REPEAT the self-test. CLEAR the DTCs.

No
GO to B5 .


B5 CHECK CIRCUITS 29 (YE/WH) AND 396 (BK/OG) FOR AN OPEN

• Key in OFF position.
• For gasoline engines, measure the resistance between the instrument cluster C220a-27, circuit 29 (YE/WH), harness side and the fuel pump module assembly C434-2, circuit 29 (YE/WH), harness side; and between the instrument cluster C220a-28, circuit 396 (BK/OG), harness side and the fuel pump module assembly C434-1, circuit 396 (BK/OG), harness side.
• For flex-fuel engines, measure the resistance between the instrument cluster C220a-27, circuit 29 (YE/WH), harness side and the fuel pump module assembly C4329-5, circuit 29 (YE/WH), harness side; and between the instrument cluster C220a-28, circuit 396 (BK/OG), harness side and the fuel pump module assembly C4329-1, circuit 396 (BK/OG), harness side.
• Are the resistances less than 5 ohms?

Yes
GO to B14 .

No
REPAIR the circuit in question. REPEAT the self-test. CLEAR the DTCs.


B6 CHECK THE FUEL PUMP MODULE FOR A SHORT TO GROUND

• Disconnect: Fuel Pump Module Assembly C434 (Gasoline Engines).
• Disconnect: Fuel Pump Module Assembly C4329 (Flex-Fuel Engines).
• NOTE: It may be normal for DTC B1204 to be present when carrying out this test step and should be ignored.
• Clear the instrument cluster DTCs. Repeat the instrument cluster self-test.
• Is DTC B1201 retrieved?

Yes
GO to B12 .

No
GO to B7 .


B7 CHECK CIRCUITS 29 (YE/WH) AND 396 (BK/OG) FOR A SHORT TOGETHER

• Disconnect: Instrument Cluster C220a.
• Measure the resistance between the instrument cluster C220a-27, circuit 29 (YE/WH), harness side and the instrument cluster C220a-28, circuit 396 (BK/OG), harness side.
• Is the resistance greater than 10,000 ohms?

Yes
GO to B8 .

No
REPAIR the circuit in question. REPEAT the self-test. CLEAR the DTCs.


B8 CHECK CIRCUIT 29 (YE/WH) FOR A SHORT TO GROUND

• Measure the resistance between the instrument cluster C220a-27, circuit 29 (YE/WH), harness side and ground.
• Is the resistance greater than 10,000 ohms?

Yes
GO to B14 .

No
REPAIR the circuit in question. REPEAT the self-test. CLEAR the DTCs.


B9 CHECK THE FUEL GAUGE OPERATION

• NOTE: Since the instrument cluster may be in anti-slosh fuel indication mode, the PID values may not match the fuel gauge readings. The actual gauge indication should be disregarded during this test step.
• Key in OFF position.
• Disconnect: Fuel Pump Module Assembly C434 (Gasoline Engines).
• Disconnect: Fuel Pump Module Assembly C4329 (Flex-Fuel Engines).
• For gasoline engines, connect 1 lead of the instrument gauge system tester to the fuel pump module assembly C434-2, circuit 29 (YE/WH), harness side, and the other lead to the fuel pump module assembly C434-1, circuit 396 (BK/OG), harness side.
• For flex-fuel engines, connect 1 lead of the instrument gauge system tester to the fuel pump module assembly C4329-5, circuit 29 (YE/WH), harness side and the other lead to the fuel pump module assembly C4329-1, circuit 396 (BK/OG), harness side.
• Key in ON position.
• Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster PID.
• NOTE: It is extremely important to confirm the gauge tester settings with an ohmmeter to ensure that the gauge tester is in the correct position. Failure to follow this check may result in inaccurate test results.
• Select and monitor the instrument cluster fuel level PID FUELLVL with the gauge tester set at 15 ohms, 53 ohms, 85 ohms, 115 ohms, and 160 ohms.
• Does the PID begin at approximately 0%, move to 25%, 50%, 75% then 100%?

Yes
DISCONNECT the instrument gauge system tester. GO to B10 .

No
DISCONNECT the instrument gauge system tester. GO to B14 .

needsmoarturbo

B10 INSPECT THE FUEL TANK

• Visually inspect the fuel tank for any damage or deformation.
• Is the fuel tank OK?

Yes
GO to B12 .

No
VERIFY the fuel pump module and fuel level sensor are not damaged. INSTALL a new fuel tank. REFER to Section 310-01 . TEST the system for normal operation.

B11 CHECK THE FUEL PUMP MODULE ASSEMBLY OPERATION

• NOTE: The fuel level sender unit resistance will measure between 7 ohms ± 2 ohms at the lower stop position and 138 ohms ± 4 ohms at the upper stop position.
• Remove the fuel pump module. Refer to Section 310-01 .
• Measure the resistance between the fuel level sensor input, component side, and the fuel level sensor output, component side, while moving the float arm between the upper stop position and the lower stop position.
• Do the resistance values fall within specifications?

Yes
GO to B13 .

No
GO to B12 .

B12 CHECK THE FUEL LEVEL SENDER

• NOTE: For flex-fuel engines, the fuel level sender unit resistance will measure between 7 ohms ± 2 ohms at the lower stop position and 138 ohms ± 4 ohms at the upper stop position. If not equipped with flex-fuel, the fuel level sender unit resistance will measure between 15 ohms ± 2 ohms at the lower stop position and 160 ohms ± 4 ohms at the upper stop position.
• Remove the fuel pump module assembly. Refer to Section 310-01 .
• NOTE: Disconnect the fuel level sensor input wire from the fuel level sensor for this measurement.
• Measure the resistance between the fuel level sensor input, harness side and the fuel level sensor ground while moving the float arm between the upper stop position and the lower stop position.
• Does the resistance fall within specifications?

Yes
INSTALL a new fuel pump module assembly. REFER to Section 310-01 . TEST the system for normal operation.

No
INSTALL a new fuel level sensor. REFER to Section 310-01 . TEST the system for normal operation.

B13 CHECK CIRCUIT 705 (LG/OG) FOR VOLTAGE

• Key in ON position.
• Measure the voltage between the fuel pump module assembly C4329-3, circuit 705 (LG/OG), harness side and ground.
• Is the voltage greater than 10 volts?

Yes
INSTALL a new flex-fuel converter wire harness. TEST the system for normal operation.

No
VERIFY CJB fuse 24 (15A) is OK. If OK, REPAIR the circuit. TEST the system for normal operation.

B14 CHECK FOR CORRECT INSTRUMENT CLUSTER OPERATION

• Disconnect all the instrument cluster connectors.
• Check for:
  • corrosion
  • damaged pins
  • pushed-out pins
• Connect all the instrument cluster connectors and make sure they seat correctly.
• Operate the system and verify the concern is still present.
• Is the concern still present?

Yes
INSTALL a new instrument cluster. REFER to Instrument Cluster in this section. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. TEST the system for normal operation.

o6S1D9e

Wrong thread. I deleted the reply and applied it to the correct thread

redfishtd

I wonder if you got the flex fuel gas tank sender thats 7 to 138 ohms whereas your normal gas engine would use the 15 to 160 ohm resistor . Check your old one .

o6S1D9e

The old one is no longer, it was installed three weeks ago and thrown away already sadly. I do have the bosch 69165 that will get referenced tomorrow.


I plan to call Ford and Bosch tomorrow and ask them what ohms range these pumps are. My mechanic thinks that I have been told to buy the wrong pump twice now since his Ford service online tool tells him that i need the -J model and not the -K model that I currently have in there. Ford told me i need the -K model of the PFS1380 and Bosch said i need the 69165. Both of the pumps are for the 139 (138.4) WB 2005 5.4L Fx4 Crew Cab w/ 5.5' Bed and a 30g tank.