Digifant II (Federal)

If the fuel pumps will not energize while attempting to start the engine perform the following tests.

1. Check the fuel pump circuit fuse in the fuse/relay panel. Replace the fuse as necessary. If the fuse tests OK continue.

NOTE: In cold weather, water in the fuel may freeze in the pumps, causing the circuit to overload and the fuse to fail. Trouble-shooting of any fuel pump fault should begin with checking the fuel pump fuse and the fuel pump relay.

Fuel Pump Relay:

Relay Terminals:

2. Remove the fuel pump relay and bridge the terminals on the relay socket that correspond to terminals #30 and #87 of the fuel pump relay with a fused jumper.

a. The fuel pump should run.
b. If the fuel pump does not run check the circuit from terminal #87 of the fuel pump relay socket to the fuel pump.
c. If the circuit is OK refer to the "Main Pump" for fuel pump testing. Testing and Inspection
d. If the fuel pump is found to be OK continue.

3. Remove the fused jumper and test for voltage at the relay socket that corresponds to terminal #30 of the fuel pump relay.

a. Reading should be 12 volts.
b. If not check the circuit to battery positive for opens.

4. Test for ground at the relay socket that corresponds to terminal #85 of the fuel pump relay while cranking the engine.

a. If ground is not present test for an open circuit to terminal #3 of the Digifant II control unit.
b. If the circuit is OK, refer to COMPUTERS AND CONTROL SYSTEMS for checking the Digifant II control unit.

5. Test for voltage at the relay socket that corresponds to terminal #86 of the fuel pump relay while cranking the engine.

a. Reading should be 12 volts.
b. If not check circuit to the ignition switch for opens.

6. If all circuits test OK replace the fuel pump relay.