Section 7
DIAGNOSTIC TESTS
TEST 28- CHECK FUEL SUPPLY
DISCUSSION:
If the engine cranks but won't start, don't overlook the obvious. The fuel supply may be low. Many RV gen- erator installations "share" the fuel tank with the vehi- cles engine. When such is the case, the installer may have used a generator fuel pickup tube that is shorter than the vehicle engines pickup tube. Therefore, the generator will run out of fuel before the vehicle engine does.
PROCEDURE:
1.Check the fuel level in the supply tank.
2.Attach a fresh fuel supply if necessary and restart. Fuel may be stale, causing a hard start.
RESULTS:
1.If necessary, replenish fuel supply.
2.If fuel is good, proceed to test 29.
TEST 29 - CHECK WIRE 14 POWER SUPPLY
DISCUSSION:
When the engine is cranked, Engine Controller Circuit Board action must deliver battery voltage to the Wire 14 circuit, or the engine will not start. This is because the Wire 14 circuit will operate the Fuel Pump and Fuel Solenoid.
PROCEDURE:
1.Set a VOM to read battery voltage (12 VDC).
2.Connect the meter positive (+) test lead to Pin 9 on the PCB, the common
3.Crank the engine and the meter should read battery voltage.
RESULTS:
1.If the meter indicated battery voltage, go to Test 19.
2.If battery voltage was NOT indicated in Step 3, replace the Engine Controller Circuit Board.
TEST 30 - CHECK WIRE 18
DISCUSSION:
Wire 18 controls sending the STOP signal to the Engine Controller Circuit Board. If Wire 18 contacts ground it will initiate a shutdown. Coach manufactur- ers sometimes install a 15 to 30 foot remote harness. A ground on Wire 18 in a remote harness can also cause a shutdown.
PROCEDURE:
1. Remove the remote harness connector from the generator and
2.Remove the J1 connector from the Engine Controller Circuit Board. Set the VOM to measure resistance. Connect one test lead to Pin Location 4. Connect the other test lead to a clean frame ground. “Infinity” should be measured.
5 6
4 3 2 1
18
Figure 7-20. – Remote Harness Connector
3.Connect one test lead to Pin Location
RESULTS:
1.If “Continuity” is measured in Step 2, repair or replace shorted Wire 18 between J1 Connector and
2.If “Continuity” was measured in Step 3, repair or replace short- ed Wire 18 between J1 Connector and remote panel connector.
3.If Wire 18 checks GOOD, proceed to Problem 8 (Section 6).
TEST 31 - CHECK FUEL SOLENOID
DISCUSSION:
The fuel solenoid is mounted to the side of the injector pump. Once energized, it pulls a plunger in from the fuel injector pump and fuel will be allowed to flow to the injectors. If the fuel solenoid is faulty, fuel will never flow to the injector pump and the engine won't run.
PROCEDURE:
1.Set a VOM to measure D/C voltage.
2.Disconnect Wire 14 to the fuel solenoid.
3.Place the positive (+) test lead on Wire 14 and the negative
4.Press the prime switch, battery voltage should be measured. If measured, skip to Step 8. If not, proceed to next Step.
5.If battery voltage is not measured, disconnect other end of Wire 14 going to the printed circuit board on Pin 9.
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