Troubleshooting; Repair - Graco GMAX II 3900 Repair Manual

Problem
E=XX is displayed
Engine will not start
False tripping of WatchDog system.
EMPTY is displayed. Pump does not
run.
Engine operates, but displacement
pump does not operate
6

Troubleshooting

Cause
Fault condition exists
Engine switch is OFF
Engine is out of gasoline
Engine oil level is low
Spark plug is disconnected or damaged Connect spark plug cable or replace spark plug
Cold engine
Fuel shutoff lever is OFF
Oil is seeping into combustion chamber Remove spark plug. Pull starter 3 to 4 times.
Operating conditions out of WatchDog
parameters
Pump output is low, page 7.
Error code displayed
Pump switch is OFF
Pressure setting too low
Fluid filter (56) is dirty
Tip or tip filter is clogged
Displacement pump piston rod is stuck
due to dried paint
Connecting rod is worn or damaged
Drive housing is worn or damaged
Electrical power is not energizing clutch
field
Clutch is worn, damaged, or incorrectly
positioned
Pinion assembly is worn or damaged
Solution
Determine fault correction from table, page 15
Turn engine switch ON
Refill gas tank. Honda Engines Owner's Man-
ual.
Try to start engine. Replenish oil, if necessary.
Honda Engines Owner's Manual.
Use choke
Move lever to ON position
Clean or replace spark plug. Start engine.
Keep sprayer upright to avoid oil seepage
Turn pressure down. Contact Graco Technical
Assistance to adjust WatchDog parameters.
Operate without WatchDog active; Manual
310892.
Reference Pressure Control repair, page 15
Turn pump switch ON
Turn pressure adjusting knob clockwise to
increase pressure.
Clean filter. Page 28.
Clean tip or tip filter. Manual 309639.
Repair pump. Manual 310894.
Replace connecting rod. Page 8.
Replace drive housing. Page 9.
Check wiring connections. Page 12.
Reference Digital Display Messages. Page 15.
Reference wiring diagram. Page 29.
With pump switch ON and pressure turned to MAXI-
MUM, use a test light to check for power between clutch
test points on control board.
Remove clutch wires from control board and
measure resistance across clutch coil. At 70° F,
the resistance must be between 1.2 +0.2Ω; if
not, replace pinion housing.
Have pressure control checked by authorized
Graco dealer
Adjust or replace clutch. Page 10.
Repair or replace pinion assembly. Page10.
Troubleshooting
310893L