Fuel Tank Sending Unit Test; Fuel Gauge System Diagnosis - Dodge D150 1990 Service Manual

INSTRUMENT PANEL AND GAUGES 8E - 5
FUEL TANK SENDING UNIT TEST
(1) Disconnect w i r e f r o m t e r m i n a l o n fuel t a n k
sending u n i t (Fig. 1).
FUEL PUMP SUPPLY
SENDING UNIT GROUND
FUEL PUMP GROUND
INPUT TO GAUGE
J908E-64
Fig. 1 Fuel Tank Sending Connector Terminals
(2) Connect w i r e to a k n o w n good sending u n i t .
(3) Connect a j u m p e r w i r e between sending u n i t
fuel pick u p tube and a good ground.
(4) Check fuel gauge as described i n following
steps. A l l o w a t least three m i n u t e s a t each test point
for gauge t o settle. L i g h t l y t a p p i n g i n s t r u m e n t clus-
ter m a y help position pointer.
(5) Clip float a r m o f sending u n i t t o i t s empty stop
(Fig. 2) a n d t u r n i g n i t i o n k e y to O N position. The
gauge should read E m p t y , plus one pointer w i d t h , or
m i n u s t w o pointer w i d t h s .
(6) Move a n d clip sending u n i t float a r m to f u l l
stop. The gauge should read F u l l , or above.
RETURN
TUBE
FULL
POSITION
FUEL LEVEL
SENDING UNIT
PICKUP
RESERVOIR
EMPTY
POSITION
RR8EC69
Fig. 2 Fuel Tank Sending Unit Test
RESULTS
(1) I f fuel gauge does not meet specifications, check
following items as possible causes;
(a) W i r i n g and connections between the gauge
sending u n i t and m u l t i p l e connector.
FUEL G A U G E SYSTEM DIAGNOSIS
1
F U E L G
1
DOES
1 READ
>AUGE
I
NOT
1
FULL 1
l
CHECK
TANK NOT FULL
FAULTY PRINTED
CIRCUIT BOARD
F U E L G A U G E
INOPERATIVE
O R ERRATIC
FAULTY WIRING OR
COMPONENTS
CHECK ALL WIRING
INCLUDING
GROUND
i
FAULTY FUEL GAUGE
SENDING UNIT
FUEL G A U G E
INACCURATE
FUEL G A U G E
DOES NOT
READ EMPTY
TANK DEFORMED
CHECK
i
TANK NOT EMPTY
CHECK
PROPER ALIGNMENT
OF PICKUP AND
SENDER ASSEMBLY.
REFER TO GROUP 14
FAULTY FUEL
GAUGE
J908E-74