"ULTRA-GLOW" DIESEL HEAT PLUGS VISUAL FAULT FINDING CHART

ALL "ULTRA-GLOW" DIESEL HEAT PLUGS UNDERGO A 100% CIRCUIT TEST BEFORE BEING RELEASED FOR DESPATCH. EVERY SINGLE GLOW PLUG HAS TO PASS A FUNCTIONAL TIME AND THERMAL TEST CONTROLLED RYAN OPTICAL PYROMETER. IT IS THUS UNLIKELY THAT CIRCUIT/PLUG FAILURES WOULD OCCUR DUE TO FAULTY MANUFACTURE LIKE MOST ENGINE COMPONENTS THAT FAIL THERE ARE ALWAYS VISUAL FEATURES WHICH WILL INDICATE THE CAUSE OF THE PROBLEM. FOR OBVIOUS REASONS AN ENGINE SET OF PLUGS WOULD , NOT FAIL SIMULTANEOUSLY DUE TO FAULTY MANUFACTURE. HOWEVER THIS IS POSSIBLE IF THE INCORRECT PLUG HAS BEEN CHOOSEN. WHERE CHOICE EXISTS, PARTICULARLY WITH JAPANESE VOLTAGES, IT IS ESSENTIAL TO SELECT THE CORRECT PART No. THE FOLLOWING CHART INDICATES TYPICAL GLOW PLUG FEATURES TO HELP YOU ANALYSE ANY POSSIBLE FAILURES.

PROBE SURFACE IS CLEAN BUT EXHIBITS RAINBOW TEMPERING COLOURATION

GLOW PLUG FEATURES	COMMON CAUSE	RESULTING FAILURE
PROBE SURFACE IS CLEAN BUT EXHIBITS RAINBOW TEMPERING COLOURATION.	(1) Starter Boosting & Jump Starting.	Glow plugs are subjected to an excessive voltage which causes the filament to melt to open circuit. NOTE ! Failure would be immediate
	(2) Over Active Timer Relay.	Glow plugs are powered beyond the normal time cycle which reduces the plug life span.
	(3) Over Active Alternator & regulator	Excessive voltage leading to filament melt and open circuit. NOTE ! Failure would be immediate
PROBE TIP IS SWOLLEN / BALLOONED	(4) Voltage Overload Due To (1), (2) Or (3).	More common on dual coil plugs where overheating is directed to the plug tip. Tip overheat occures and start up compression distorts probe and breaks filament.
SHEARED GLOW PLUG TERMINAL CONNECTION	(5) Excessive Tightening Or Retainer (6) Mishandling
PROBE IS COATED IN A ROUGH LAYER OF RAISED CARBON	(7) Ingress Of Oil Due To Wear Via Piston Rings And / Or Valve Guides etc., etc.	Plug probe becomes layered with carbonised fuel / and or oil. The probe can no longer dissipate heat and thus probe core and filament overheat to the point of malfunction. NOTE ! Failure would not be immediate and might not affect all plugs
	(8) Excessive Fueling Due To Worn Diesel Pump Or Worn Injectors.
PROBE IS COATED IN A LIGHT SMOOTH COAT OF SOOT OR "BEIGE" COLOURED SCALE	(9) Under Fueling Due To Diesel Pump Or Inefficient Injector Spray.	Plug environment is subjected to over heating due to a weak mixture. Constant non operation overheat reduces the probe life span. NOTE ! Failure would not be immediate and might not affect all plugs
TERMINAL INSULATOR BURNT AWAY	(10) Loose Or Burnt Connection Between Loom And Plug Terminal	Arc-ing during operation, particularly on a hot engine, can lead to failure of the terminal insulator sleeve. A complete system short would result.
PROBE TIP IS COMPLETELY BURNT AWAY EXPOSING CORE	(11) Any Of The Previously Mentioned Causes (1) To (9), But In Particular (1), (2) & (3). Compounded by General Overheating.	Glow plugs are subjected to massive voltage overload with possible prolonged energy cycle due to faulty timer. General overheating will encourage burn out. Plug tip literally melts to destruction.
GLOW PLUG BODY IS SOOTY RIGHT UPTO & INCLUDING THE LOWER BODY THREAD	(12) Seating Cone Has Not Sealed Due To Lack Of Torque Or To Tightness Of Thread	Compression Ratio is reduced promoting over use of plugs for initial start up. Damage to head thread can also result.