Gas Guage
Thread Starter
|
New User
Joined: Aug 2004
Posts: 20
Likes: 0
Gas Guage
I have a 96 shot wheel base, std cab Ranger. Has 125000 miles on it. When my gas guage gets to 1/4 tank mark, it starts rising. If I let it go for 20 miles , it will go to almost 1/2 tank mark. I have never had a truck that produced gas before just by driving.
Can anybody tell me whats happening to it and what a posible fix might be? Thanks...
Can anybody tell me whats happening to it and what a posible fix might be? Thanks...
Post Fiend
Joined: Dec 2001
Posts: 10,562
Likes: 4
From: South Jersey
The instrument cluster gauge amplifier is a small printed circuit board which latches into a pocket on the back of the instrument cluster.
PINPOINT TEST A: FUEL LEVEL READS INACCURATELY
A1 VERIFY POWER AT FUSE 11 — LOAD SIDE
Key ON.
Using Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, verify system voltage at the load side of fuse 11.
Is the voltage greater than 10 volts?
Yes
GO to A3 .
No
GO to A2 .
A2 VERIFY POWER AT FUSE 11 — FEED SIDE
Key ON.
Using Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, verify system voltage at the feed side of the fuse 11.
Is the voltage greater than 10 volts?
Yes
REPLACE the fuse. RETEST system.
No
REPAIR the wiring to the fuse panel. RETEST system.
A3 VERIFY POWER AT CLUSTER CIRCUIT 640 (R/Y)
Have cluster connector(s) remain intact.
Partially remove the instrument cluster from the instrument panel .
Key ON.
Measure the voltage on Circuit 640 (R/Y) at the instrument cluster connector to ground.
Is the voltage greater than 10 volts?
Yes
GO to A4 .
No
REPAIR Circuit 640 (R/Y). RETEST system.
A4 VERIFY GROUND CIRCUIT 570 (BK/W)
CAUTION: Before checking the continuity of any circuit, make sure there is no voltage present in the circuit prior to switching the test equipment to the resistance function to avoid damage to equipment. Refer to the test equipment user's manual for additional information.
Use an ohmmeter to check the continuity of the ground wire at the instrument cluster connector to ground.
Is the resistance less than 1 ohm?
Yes
GO to A5 .
No
REPAIR Circuit 570 (BK/W). RETEST system.
A5 CHECK FUEL GAUGE (EMPTY)
Key OFF.
Disconnect the fuel gauge sending unit.
Connect one lead of the Rotunda Instrument Gauge System Tester 021-00055 or equivalent to the fuel sending unit input wire Circuit 29 (Y/W) at the fuel gauge sending unit connector. Connect the other lead to ground.
Set the tester to 22 ohms.
Key ON.
Wait one minute.
Read the fuel gauge.
Does the fuel gauge read E (empty)?
Yes
GO to A9 .
No
GO to A6 .
A6 RECHECK FUEL GAUGE (EMPTY)
Place the key in the OFF position. Then to the ON position. Tap on the instrument panel .
Wait one minute.
Read the fuel gauge.
Does the fuel gauge read E (empty)?
Yes
GO to A9 .
No
GO to A7 .
A7 CHECK PRINTED CIRCUIT BOARD
Key OFF.
Disconnect the instrument cluster and instrument cluster gauge amplifier .
Measure the resistance of the circuit between the "SIG" terminal of the fuel gauge and the instrument cluster gauge amplifier .
Is the resistance less than 1 ohm?
Yes
GO to A8 .
No
Ranger and Explorer: REPLACE instrument cluster printed circuit as described in Removal and Installation, Instrument Cluster in this section.
Aerostar: REPLACE instrument cluster as described in Removal and Installation, Instrument Cluster in this section.
A8 CHECK INSTRUMENT CLUSTER GAUGE AMPLIFIER (EMPTY)
Turn the key to OFF position. Remove the instrument cluster. Inspect the instrument cluster printed circuit .
Remove the instrument cluster gauge amplifier . Connect a jumper wire from the Rotunda Instrument Gauge System Tester 021-00055 or equivalent directly to the fuel gauge "SIG" terminal.
Install the instrument cluster.
Turn the key to the ON position.
Read the fuel gauge.
Does the fuel gauge read E (empty)?
Yes
REPLACE the Instrument Cluster Gauge Amplifier as described in Removal and Installation in this section. GO to A5 .
No
REPLACE the fuel gauge as described in Removal and Installation in this section. INSTALL the Instrument Cluster Gauge Amplifier as described in Removal and Installation in this section and RETURN to A5 .
A9 CHECK FUEL GAUGE SENDING UNIT WIRE
Key OFF.
Disconnect the instrument cluster and the fuel gauge sending unit.
Measure the resistance of Circuit 29 (Y/W) between the instrument cluster and the fuel gauge sending unit.
Is the resistance less than 1 ohm?
Yes
GO to A10 .
No
SERVICE Circuit 29 (Y/W) between the instrument cluster and the fuel gauge sending unit. RETEST system.
A10 CHECK FUEL SENDING UNIT GROUND
Key OFF.
Measure the resistance of Circuit 651 (BK/Y) (Ranger and Explorer) or "BK/W" (Aerostar) wire at the fuel gauge sending unit connector to ground at battery.
Is the resistance less than 1 ohm?
Yes
GO to A11 .
No
SERVICE Circuit 651 (BK/Y) (Ranger and Explorer) or "BK/W" (Aerostar) wire from the fuel gauge sending unit to ground.
A11 CHECK FUEL GAUGE (FULL)
Key OFF.
Disconnect the fuel gauge sending unit.
Connect one lead of the Rotunda Instrument Gauge System Tester 021-00055 or equivalent to Circuit 29 (Y/W) at the fuel gauge sending unit connector and the other lead to ground.
Set the tester to 145 ohms.
Key ON.
Wait one minute.
Read the fuel gauge.
Does the fuel gauge read F (full)?
Yes
GO to A13 .
No
GO to A12 .
A12 CHECK INSTRUMENT CLUSTER GAUGE AMPLIFIER (FULL)
Turn the key to OFF position. Remove the instrument cluster. Inspect the instrument cluster printed circuit . Remove the instrument cluster gauge amplifier . Connect the jumper wire from the Rotunda Instrument Gauge System Tester 021-00055 or equivalent directly to the fuel gauge "SIG" terminal.
Install the instrument cluster.
Turn the key to the ON position.
Read the fuel gauge.
Does the fuel gauge read F (full)?
Yes
REPLACE the Instrument Cluster Gauge Amplifier as described in Removal and Installation in this section. GO to A5 .
No
REPLACE the fuel gauge as described in Removal and Installation in this section. RETURN to A5 .
A13 FUEL TANK INSPECTION
Inspect fuel tank for distortion or damage.
Is fuel tank damaged?
Yes
REPLACE fuel tank . REFER to Section 10-01 .
No
GO to A14 .
A14 TEST BOX CHECK — EMPTY STOP
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) and the other lead to sender ground Circuit 651 (BK/Y).
When the float rod is against the empty stop (closest to fuel filter).
Does DVOM read 14-18 ohms?
Yes
GO to A15 .
No
REPLACE fuel sender.
A15 TEST BOX CHECK — FULL STOP
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) and the other lead to sender ground Circuit 651 (BK/Y).
When the float rod is against the full stop.
Does DVOM read 154-162 ohms?
Yes
GO to A16 .
No, less than 154 or greater than 162 ohms
REPLACE fuel sender.
A16 TEST BOX CHECK — FLOAT ROD TRAVEL
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) and the other lead to sender ground Circuit 651 (BK/Y).
Move float rod slowly from FULL to EMPTY stop position.
Does ohmmeter reading decrease slowly?
Yes
GO to A17 .
No
REPLACE fuel sender. REFER to Section 10-01 .
A17 HARNESS CONNECTOR CHECK — EMPTY STOP
Reattach all fuel indication connectors.
Move float rod to empty stop position.
Place key in the ON position.
Wait 60 seconds.
Read fuel gauge.
Does fuel gauge read empty?
Yes
GO to A18 .
No
GO to A7 .
A18 HARNESS CONNECTOR CHECK — FULL STOP
Reattach all fuel indication connectors.
Move float rod to full-stop position.
Place key in the ON position.
Wait 60 seconds.
Read fuel gauge.
Does fuel gauge read full?
Yes
GO to A19 .
No
GO to A7 .
A19 INSPECT FUEL SENDER
Inspect float and float rod.
Is float rod distorted, hitting filter, filled with fuel or loose on float rod?
Yes
REPLACE fuel sender. REFER to Section 10-01 .
No
GO to A20 .
A20 PIGTAIL HARNESS CHECK — EXPLORER
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) in the pigtail connector and the other lead to the corresponding below the flange rivet.
Check sending unit ground Circuit 651 (BK/Y) in same manner as above.
Is ohmmeter reading greater than 1 ohm?
Yes
REPLACE fuel sending unit. REFER to Section 10-01 .
No
Pigtail OK.
PINPOINT TEST A: FUEL LEVEL READS INACCURATELY
A1 VERIFY POWER AT FUSE 11 — LOAD SIDE
Key ON.
Using Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, verify system voltage at the load side of fuse 11.
Is the voltage greater than 10 volts?
Yes
GO to A3 .
No
GO to A2 .
A2 VERIFY POWER AT FUSE 11 — FEED SIDE
Key ON.
Using Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, verify system voltage at the feed side of the fuse 11.
Is the voltage greater than 10 volts?
Yes
REPLACE the fuse. RETEST system.
No
REPAIR the wiring to the fuse panel. RETEST system.
A3 VERIFY POWER AT CLUSTER CIRCUIT 640 (R/Y)
Have cluster connector(s) remain intact.
Partially remove the instrument cluster from the instrument panel .
Key ON.
Measure the voltage on Circuit 640 (R/Y) at the instrument cluster connector to ground.
Is the voltage greater than 10 volts?
Yes
GO to A4 .
No
REPAIR Circuit 640 (R/Y). RETEST system.
A4 VERIFY GROUND CIRCUIT 570 (BK/W)
CAUTION: Before checking the continuity of any circuit, make sure there is no voltage present in the circuit prior to switching the test equipment to the resistance function to avoid damage to equipment. Refer to the test equipment user's manual for additional information.
Use an ohmmeter to check the continuity of the ground wire at the instrument cluster connector to ground.
Is the resistance less than 1 ohm?
Yes
GO to A5 .
No
REPAIR Circuit 570 (BK/W). RETEST system.
A5 CHECK FUEL GAUGE (EMPTY)
Key OFF.
Disconnect the fuel gauge sending unit.
Connect one lead of the Rotunda Instrument Gauge System Tester 021-00055 or equivalent to the fuel sending unit input wire Circuit 29 (Y/W) at the fuel gauge sending unit connector. Connect the other lead to ground.
Set the tester to 22 ohms.
Key ON.
Wait one minute.
Read the fuel gauge.
Does the fuel gauge read E (empty)?
Yes
GO to A9 .
No
GO to A6 .
A6 RECHECK FUEL GAUGE (EMPTY)
Place the key in the OFF position. Then to the ON position. Tap on the instrument panel .
Wait one minute.
Read the fuel gauge.
Does the fuel gauge read E (empty)?
Yes
GO to A9 .
No
GO to A7 .
A7 CHECK PRINTED CIRCUIT BOARD
Key OFF.
Disconnect the instrument cluster and instrument cluster gauge amplifier .
Measure the resistance of the circuit between the "SIG" terminal of the fuel gauge and the instrument cluster gauge amplifier .
Is the resistance less than 1 ohm?
Yes
GO to A8 .
No
Ranger and Explorer: REPLACE instrument cluster printed circuit as described in Removal and Installation, Instrument Cluster in this section.
Aerostar: REPLACE instrument cluster as described in Removal and Installation, Instrument Cluster in this section.
A8 CHECK INSTRUMENT CLUSTER GAUGE AMPLIFIER (EMPTY)
Turn the key to OFF position. Remove the instrument cluster. Inspect the instrument cluster printed circuit .
Remove the instrument cluster gauge amplifier . Connect a jumper wire from the Rotunda Instrument Gauge System Tester 021-00055 or equivalent directly to the fuel gauge "SIG" terminal.
Install the instrument cluster.
Turn the key to the ON position.
Read the fuel gauge.
Does the fuel gauge read E (empty)?
Yes
REPLACE the Instrument Cluster Gauge Amplifier as described in Removal and Installation in this section. GO to A5 .
No
REPLACE the fuel gauge as described in Removal and Installation in this section. INSTALL the Instrument Cluster Gauge Amplifier as described in Removal and Installation in this section and RETURN to A5 .
A9 CHECK FUEL GAUGE SENDING UNIT WIRE
Key OFF.
Disconnect the instrument cluster and the fuel gauge sending unit.
Measure the resistance of Circuit 29 (Y/W) between the instrument cluster and the fuel gauge sending unit.
Is the resistance less than 1 ohm?
Yes
GO to A10 .
No
SERVICE Circuit 29 (Y/W) between the instrument cluster and the fuel gauge sending unit. RETEST system.
A10 CHECK FUEL SENDING UNIT GROUND
Key OFF.
Measure the resistance of Circuit 651 (BK/Y) (Ranger and Explorer) or "BK/W" (Aerostar) wire at the fuel gauge sending unit connector to ground at battery.
Is the resistance less than 1 ohm?
Yes
GO to A11 .
No
SERVICE Circuit 651 (BK/Y) (Ranger and Explorer) or "BK/W" (Aerostar) wire from the fuel gauge sending unit to ground.
A11 CHECK FUEL GAUGE (FULL)
Key OFF.
Disconnect the fuel gauge sending unit.
Connect one lead of the Rotunda Instrument Gauge System Tester 021-00055 or equivalent to Circuit 29 (Y/W) at the fuel gauge sending unit connector and the other lead to ground.
Set the tester to 145 ohms.
Key ON.
Wait one minute.
Read the fuel gauge.
Does the fuel gauge read F (full)?
Yes
GO to A13 .
No
GO to A12 .
A12 CHECK INSTRUMENT CLUSTER GAUGE AMPLIFIER (FULL)
Turn the key to OFF position. Remove the instrument cluster. Inspect the instrument cluster printed circuit . Remove the instrument cluster gauge amplifier . Connect the jumper wire from the Rotunda Instrument Gauge System Tester 021-00055 or equivalent directly to the fuel gauge "SIG" terminal.
Install the instrument cluster.
Turn the key to the ON position.
Read the fuel gauge.
Does the fuel gauge read F (full)?
Yes
REPLACE the Instrument Cluster Gauge Amplifier as described in Removal and Installation in this section. GO to A5 .
No
REPLACE the fuel gauge as described in Removal and Installation in this section. RETURN to A5 .
A13 FUEL TANK INSPECTION
Inspect fuel tank for distortion or damage.
Is fuel tank damaged?
Yes
REPLACE fuel tank . REFER to Section 10-01 .
No
GO to A14 .
A14 TEST BOX CHECK — EMPTY STOP
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) and the other lead to sender ground Circuit 651 (BK/Y).
When the float rod is against the empty stop (closest to fuel filter).
Does DVOM read 14-18 ohms?
Yes
GO to A15 .
No
REPLACE fuel sender.
A15 TEST BOX CHECK — FULL STOP
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) and the other lead to sender ground Circuit 651 (BK/Y).
When the float rod is against the full stop.
Does DVOM read 154-162 ohms?
Yes
GO to A16 .
No, less than 154 or greater than 162 ohms
REPLACE fuel sender.
A16 TEST BOX CHECK — FLOAT ROD TRAVEL
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) and the other lead to sender ground Circuit 651 (BK/Y).
Move float rod slowly from FULL to EMPTY stop position.
Does ohmmeter reading decrease slowly?
Yes
GO to A17 .
No
REPLACE fuel sender. REFER to Section 10-01 .
A17 HARNESS CONNECTOR CHECK — EMPTY STOP
Reattach all fuel indication connectors.
Move float rod to empty stop position.
Place key in the ON position.
Wait 60 seconds.
Read fuel gauge.
Does fuel gauge read empty?
Yes
GO to A18 .
No
GO to A7 .
A18 HARNESS CONNECTOR CHECK — FULL STOP
Reattach all fuel indication connectors.
Move float rod to full-stop position.
Place key in the ON position.
Wait 60 seconds.
Read fuel gauge.
Does fuel gauge read full?
Yes
GO to A19 .
No
GO to A7 .
A19 INSPECT FUEL SENDER
Inspect float and float rod.
Is float rod distorted, hitting filter, filled with fuel or loose on float rod?
Yes
REPLACE fuel sender. REFER to Section 10-01 .
No
GO to A20 .
A20 PIGTAIL HARNESS CHECK — EXPLORER
Connect one lead of a Rotunda Digital Volt-Ohmmeter 014-00407 or equivalent, to the fuel sender signal lead Circuit 29 (Y/W) in the pigtail connector and the other lead to the corresponding below the flange rivet.
Check sending unit ground Circuit 651 (BK/Y) in same manner as above.
Is ohmmeter reading greater than 1 ohm?
Yes
REPLACE fuel sending unit. REFER to Section 10-01 .
No
Pigtail OK.
Thread Starter
|
New User
Joined: Aug 2004
Posts: 20
Likes: 0
Wow......sounds like that is over my head . I better leave well enough alone maybe . The guage reads perfect till I get to 1/4 tank . I have been just filling it back up when it starts that. Thanks again Ken for your replies..... Larry
Thread
Thread Starter
Forum
Replies
Last Post
carolinaskifftom
1987 - 1996 F150 & Larger F-Series Trucks
3
Jul 23, 2011 07:48 AM
