Fuel Gauge - Inaccurate/Erratic/Sticking

91ford19

Article No.
91-11-9

05/30/91


GAUGE - FUEL - INACCURATE, ERRATIC OR STICKS IN ONE POSITION - EFI ENGINES ONLY


FORD: 1989-91 FESTIVA


ISSUE: The fuel gauge reading may be inaccurate, erratic or may stick in one position. This usually occurs because the sending unit float lever is out of adjustment or the float rod is hung-up on the fuel pump filter.

ACTION: If service is required, use the following diagnosis and service procedure to ensure an accurate fuel gauge reading.


INACCURATE OR ERRATIC FUEL GAUGE

1. Check the accuracy of the fuel gauge by using a Rotunda Instrument Gauge System Tester (012-00055).

a. Release the rear seat(s). Fold the seat backs down and move the seat base forward to the back of the front seats.

b. Remove the carpet retainers and fold the carpet back.

c. Disconnect the C-400 connector from the fuel pump.

NOTE: THE ACCESS PLATE DOES NOT NEED TO BE REMOVED TO DISCONNECT THE C-400 CONNECTOR.

Figure 1:

Figure 2:

d. Test the gauge for accuracy. At the sending unit connector C-400, apply the appropriate resistance, Figure 1, to the gauge between the yellow and black wires, Figure 2.

e. Confirm that the gauge reads in its respective location.

f. If not within specifications, replace the gauge following the procedures described in the 1989-91 Festiva Shop Manual, Section 13-03. If within specification, proceed to Step # 2.

2. Remove the access plate.

3. Remove the sending unit from the fuel tank.

Figure 3:

4. Check for a loose ground screw on the sending unit, Figure 3. If the ground screw is tight, proceed to Step # 4.


5. Remove the sender assembly from the fuel pump.

6. Verify the shape of the sending unit float rod by using the diagram provided in Figure 3.

7. Check the resistance and accuracy of the sending unit using an ohm meter. The specifications are as follows for the resistance values at each float position. See Figure 3 for position locations.

^ Position A - 3.0 ohms

^ Position B - 32.5 ohms

^ Position C - 110.0 ohms

8. Check the "trueness" of the sending unit float lever.

a. Place the sending unit on the diagram and align it with the outline of the sending unit on the diagram.

b. Lower the float level until it reaches its furthest point of travel (Figure 3, Position C). It must line up with the diagram to be within specification.

c. Raise the float lever until it reaches its furthest point of travel upward (Figure 3, Position A). It must line up with the diagram to be within specification.


d. If the float lever lines up at both points (A & C), the float rod is "true". If it does not line up at the correct points, adjust the float rod or replace the sending unit.

FUEL GAUGE STICKS IN ONE POSITION

Check to see if the sending unit float rod is hung up on the fuel pump filter.

1. Loosen the sending unit from the fuel tank.

2. Partially lift the sending unit from the tank and move the float rod with your finger to make sure that it moves without catching on the fuel pump filter.

3. If the sending unit float rod does not move freely, remove the sending unit from the fuel and free up the float rod.


4. Reinstall the sending unit.

PART NUMBER PART NAME CLASS

F0BZ-9305-A Fuel Gauge (Non-Tach Cluster, C
'90-'91 Units)
F0BZ-9305-B Fuel Gauge (Tach-Cluster, '90 C
Units)
E8BZ-9305-A Fuel Gauge (Non-Tach Cluster, C
'89 Units)
E8BZ-9305-B Fuel Gauge (Tach-Cluster, '89 C
Units)
F0BZ-9275-A Sending Unit ('90 -'91 Units) B
E9BZ-9275-A Sending Unit ('89 Units) B

OTHER APPLICABLE ARTICLES: NONE
WARRANTY STATUS: Eligible Under Basic Warranty
Coverage
OPERATION DESCRIPTION TIME
911109A Diagnose - Adjust - 0.5 Hrs.
Replace Fuel
Pump/Sending Unit
911109B Diagnose - Replace Fuel 0.8 Hrs.
Gauge
DEALER CODING
BASIC PART NO. CONDITION CODE
9275 09
OASIS CODES: 204000, 204200