Service manual

G420F(FE) Service Manual 270 Chapter 8. Basic Troubleshooting
Rough, Unstable, Incorrect Idle, or Stalling (cont’d.)
PROBABLE CAUSE CORRECTIVE ACTION
Excess flow valve closed
Reset excess flow valve.
• Close liquid valve.
• Wait for a “click” sound. Slowly open liquid valve.
Clogged fuel filter
Repair/replace as required
See Chapter 4 Fuel Filter Replacement
Plugged fuel line
Remove obstruction from the fuel line.
• Close liquid fuel valve.
• Using caution, disconnect the fuel line (some
propane may escape).
• Clear obstruction with compressed air.
• Re-connect fuel line.
• Slowly open liquid fuel valve & leak test.
Fuel lock-off malfunction
Repair/replace fuel lock-off.
See Chapter 4 Fuel Lock-Off.
Faulty vapor connection
between the pressure regulator/converter and the
mixer
Check connection.
• Verify no holes in hose.
• Clamps must be tight.
• Look for kinked, pinched and/or collapsed hose.
Pressure regulator freezes
Check level in cooling system:
• Must be full, check coolant strength
• -35°F (-37°C) minimum
Check coolant hoses.
• Watch for kinks and/or pinched hoses.
• Verify one pressure hose and one return hose.
Test regulator. See Chapter 6
Vacuum leak
Check for vacuum leaks.
• Between mixer and throttle body
• Between throttle body and intake manifold
• Between intake manifold and cylinder head
Related MIL Faults:
EST faults
ETC Sticking fault
Pre-catalyst adapts error