JLG 450A_AJ Series II Service Manual User Manual
Page 135
SECTION 3 - CHASSIS & TURNTABLE
3121290
– JLG Lift –
3-95
14
Using a DVOM, check resistance of Low Pressure Lock-off (LPL).
Is resistance within specified range?
12W - 16W
Go to Step 15
Go to Step 23
15
1. Turn ignition OFF.
2. Close LPG tank manual shut-off valve.
LIQUID LPG MAY BE PRESENT WHEN DISCONNECTING LPG FUEL LINES. PERFORM
THIS STEP IN A WELL VENTILATED AREA.
3. Loosen fuel inlet hose fitting at LPL inlet.
Was fuel present when fitting was loosened?
- -
Go to Step 23
Go to Step 17
16
1. Turn OFF ignition.
2. Connect test light to chassis ground and probe pin A of LPL connec-
tor.
3. Crank engine. Test light should illuminate.
Does test light illuminate?
- -
Go to Step 20
Go to Step 21
17
1. Remove LPG fuel filter / LPL.
2. Remove filter from LPL.
3. Empty contents of inlet side of fuel filter onto a clean surface.
4. Inspect contents of LPG fuel filter for an excessive amount of foreign
material or water. If necessary, locate and repair source of contamina-
tion.
5. Verify LPG fuel filter is not restricted or plugged.
Was a problem found?
- -
Go to Step 19
Go to Step 18
18
Fuel supply system or hoses are plugged or restricted. Locate and
repair the problem.
Is action complete?
- -
Go to Step 26
- -
19
Replace fuel filter. Refer to Fuel Filter Replacement.
Is action complete?
- -
Go to Step 26
- -
20
Repair open circuit in lock-off ground circuit.
Is action complete?
- -
Go to Step 26
- -
21
Repair open circuit in lock-off power circuit.
Is action complete?
- -
Go to Step 26
- -
22
Replace LPR. Refer to Low Pressure Regulator Replacement.
Is action complete?
- -
Go to Step 26
- -
23
Replace Lock-Off. Refer to Lock-off Replacement.
Is action complete?
- -
Go to Step 26
- -
24
Replace mixer assembly. Refer to Fuel Mixer Replacement.
Is action complete?
- -
Go to Step 26
- -
25
Fuel supply system is operating normally, if a failure of the control
solenoids is suspected. Refer to Fuel Control System Diagnosis.
1. Install test plug in LPR secondary chamber.
2. If you were sent to this routine by another diagnostic chart, return to
previous diagnostic procedure.
Is action complete?
- -
System OK
- -
26
1. Disconnect all test equipment
2. Install primary and secondary test port plugs.
3. Start engine.
4. Using SNOOP or equivalent, leak check test port plugs.
Is action complete?
- -
System OK
- -
Table 3-12. LPF Fuel System Diagnosis
STEP
ACTION
VALUE(S)
YES
NO