Service manual

90-898303
3-8
3.0L Fuel Pump Test
VOLTAGE TEST CHART
Engine Mode Black Meter Lead To
Engine Ground, Red
Meter Lead To:
Approx. Voltage
Reading
If approx. Voltage Is
Not Obtained, This
Indicates:
All Models (+) terminal of fuel pump. 12-13.5 Volts If reading is below 12
volts, the battery is bad
or discharged, or a bad
connection(s) on battery
harness. If reading is
higher than 13.5 volts,
the battery is over-
charged.
Ignition key in “OFF”
position.
(-) terminal of fuel pump. Same reading should be
obtained as reading in
check No. 1 (above).
If reading is lower than in
check 1, the fuel pump
or wire in harness is
defective.
Ignition key in “ON”
position and engine NOT
running.
(-) terminal of fuel pump. 1 volt or less (voltage
should then raise to 12-
13.5 volts after approx.
15 seconds).
Defective ECM or fuel
pump. *
Engine being cranked. (-) terminal of fuel pump. 1 volt or less. Defective ECM or fuel
pump. *
Engine running below
approx. 3000 RPM.
(-) terminal of fuel pump. The voltage will vary as
engine RPM changes.
Defective ECM or fuel
pump. *
Engine running above
approx. 3000 RPM.
(-) terminal of fuel pump. 1 volt or less. Defective ECM or fuel
pump. *
* Check for proper electrical operation of electric fuel pump.
a) Negative Terminal