Troubleshooting - Glow Plugs

Destroyed/lacking probe tip

Cause:

Ignition unit failure.
Incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.

Remedy:

Check the correspondence of ignition unit with the car type and proper installation of the ignition unit.
Check glow plug installation hole for carbon fouling.
Replace your plugs.

Dimples on the probe tip

Cause:

Ignition unit failure.
Incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.

Remedy:

Check the correspondence of ignition unit with the car type and proper installation of the ignition unit.
Check glow plug installation hole for carbon fouling.
Replace your plugs.

Broken probe tip

Cause:

Glowing time too long or voltage too high (12-V glow plug used in the 24-V system or vice versa).
Alternator & regulator failure.

Remedy:

Check glow plug regulator (contacts).
Check on-board voltage and glow plug voltage.
Check charging system voltage.
Replace your plugs.

Swollen probe tip

Cause:

Excessive voltage (12-V glow plug used in the 24-V system or vice versa)
Alternator & regulator failure.
Inappropriate storage (moisture).

Remedy:

Check on-board voltage and glow plug operation voltage.
Check charging system.
Check storage conditions.
Replace your plugs.

Bulging ring on the probe tip

Cause:

Oil in the combustion chamber (probable cause: car engine wear).

Remedy:

Check piston tightness in engine cylinders.
Check engine oil consumption.
Replace your plugs.

Probe deformation

Cause:

Ignition unit failure.
Incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.
Glowing time too long or excessive voltage (12-V glow plug used in the 24-V system or vice versa).
Alternator & regulator failure.
Injection unit operation/timing failure.

Remedy:

Check the correspondence of the ignition unit with the car type and proper installation of the ignition unit.
Check glow plug installation hole for carbon fouling. Check glow plug regulator (contacts).
Check on-board voltage and glow plug voltage.
Check charging system voltage.
Check fuel injection timing.
Replace your plugs.

Lacking probe

Cause:

Ignition unit failure.
Incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.
Injection unit operation/timing failure.
Damaged glow plug installation hole thread in the cylinder head/not tightened glow plug causing incorrect plug seating.

Remedy:

Check the correspondence of the ignition unit with the car type and proper installation of the ignition unit.
Check the glow plug installation hole thread in the cylinder head for damage/carbon fouling.
Check ignition pump timing.
Replace your plugs.

Probe perforation, fissures or melting close to the glow plug body

Cause:

Ignition unit failure.
Incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.
Injection unit operation/timing failure.
Damaged glow plug installation hole thread in the cylinder head/not tightened glow plug causing incorrect plug seating.

Remedy:

Check the correspondence of the ignition unit with the car type and proper installation of the ignition unit.
Check the glow plug installation hole thread in the cylinder head for damage/carbon fouling.
Check ignition pump timing.
Replace your plugs.

Probe in contact with the glow plug body

Cause:

Tightening torque too high.
Inappropriate tool used or damage of the cylinder head hole thread.

Remedy:

Check the cylinder head hole thread for damage/carbon fouling.
Check correct glow plug tightening
Replace your plugs.

Carbon fouling between the plug body and the probe glow

Cause:

Ignition unit failure.
Incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.
Ignition pump operation/timing failure.

Remedy:

Check the correspondence of the ignition unit with the car type and proper installation of the ignition unit.
Check the glow plug installation hole thread in the cylinder head for carbon fouling.
Check ignition pump and its timing.
Replace your plugs.

Carbon fouling in the glow plug seat

Cause:

Incorrect glow plug seating.

Remedy:

Check the glow plug installation hole thread in the cylinder head for damage/ carbon fouling.
Check correct tightening of the glow plug.
Replace your plugs.

Damaged glow plug hexagon/ thread

Cause:

Tightening torque too high.
Inappropriate tool used or damage of the cylinder head hole thread.

Remedy:

Check the glow plug installation hole thread in the cylinder head for damage/ carbon fouling.
Check correct tightening of the glow plug.
Replace your plugs.

Power supply terminal bent

Cause:

Tightening torque too high. Inappropriate tool used or damage of the cylinder head hole thread.

Remedy:

Check the glow plug installation hole thread in the cylinder head for damage/ carbon fouling.
Check correct tightening of the glow plug.
Replace your plugs.

Power supply terminal broken off

Cause:

Tightening torque too high.
Inappropriate tool used or damage of the cylinder head hole thread.

Remedy:

Check the glow plug installation hole thread in the cylinder head for damage/carbon fouling.
Check correct tightening of the glow plug.
Replace your plugs.

Other damage

Cause:

Ignition unit failure, incorrect/irregular fuel jet direction.
Incorrect number or size of sealing causing incorrect spraying position.
Glowing time too long.
Ignition pump operation/timing failure.

Remedy:

Check the correspondence of the ignition unit with the car type and proper installation of the ignition unit.
Check the glow plug installation hole thread in the cylinder head for carbon fouling.
Check glow plug regulator (contacts).
Check the ignition pump and its timing.
Replace your plugs.