Check Fuel Pump - Guardian 4700 Repair Manual

Battery Voltage should be measured when the Primer Switch is
activated.
PIN 2 - WIRE NO. 14A
PIN 1 - WIRE NO. 0
Figure 7-12. – Harness End of Connector 2
5. Set the VOM to measure resistance at the "Rx1" scale and
zero the meter.
a. Disconnect Wire No. 14 from the Primer
Switch.
b. Connect the meter test leads across the
Wires 14 and 14A terminals of the Switch.
c. With the switch NOT actuated, the meter
should read "continuity".
RESULTS:
1. If battery voltage is not indicated in Step 2, check Wire 15 between
the Primer Switch and the 7.5 amp fuse for an open condition.
2. If battery voltage is indicated in Step 2 but not in Step 3,
replace the Primer Switch.
3. If Battery Voltage was indicated in Step 3, but not in Step 4,
repair or replace defective Wire No. 14A between Primer
Switch and Fuel Pump Connector 2.
4. If the meter reads anything other than "continuity" in Step 5,
replace the Primer Switch.
5. If the Primer Switch checks good, go to Test 20.
TEST 20- CHECK FUEL PUMP
DISCUSSION:
An inoperative Fuel Pump will (a) prevent the priming
function from working and (b) prevent the engine from
starting.
PROCEDURE:
1. Remove Fuel Filter and verify that filter is not clogged. Replace
filter if necessary.
2. Verify that fuel is available to Fuel Filter inlet. Use an alterna-
tive fuel supply if questionable.
3. Remove air filter access panel and air filter. Remove fuel hose
from pump. Place a suitable container to catch fuel from fuel
pump line. Activate fuel primer switch. Pump should operate
and fuel should flow. If pump does not operate, proceed to
Step 4.
4. In Test 19, Battery Voltage was checked at Connector 2. This
step will test the ground wire. Disconnect Connector 2 at the
Fuel Pump. Set the VOM to measure resistance. Connect one
test lead to Wire No. 0, (Pin 1 of Connector 2) that goes to the
Control Panel. Connect the other test lead to a clean frame
ground. Continuity should be measured.
5. To test for an open fuel pump coil, connect one test lead to the
Red Wire (Pin 2 of Connector 2) going to the fuel pump. Connect
the other test lead to the Black Wire (Pin 1 of Connector 2) going
to the Fuel Pump. The VOM should indicate Fuel Pump coil
resistance of about 29.5 kΩ. (Currant draw of the pump at nomi-
nal voltage is approximately 1.4 amperes MAXIMUM).
Short to Ground:
6. To test for a shorted fuel pump coil, connect one test lead to
the Red Wire (Pin 2 of Connector 2). Connect the other test
lead to the fuel pump housing. "Infinity" should be measured.
F L F L
O W O W
Figure 7-13. – Electric Fuel Pump
RESULTS:
1. If "Continuity" was not measured in Step 4, repair or replace
Wire No. 0 between Connector 2 and the ground terminal.
2. If "Continuity" is measured in Step 4, but pump does not oper-
ate in Step 3, replace the Fuel Pump.
Section 7
DIAGNOSTIC TESTS
Page 39