Fuel Injector Leaking Causes, Indication, Action

Fuel Injector leaking causes, Indication, Action  
              Because of the repeated operation leads weakening of springs, erosion and enlarging of atomization hole, wear of needle and nozzle seats etc causes the fuel valve leaky may requires immediate overhaul. 
Causes And Faults

Causes
leakage from nozzle:- Leakage from nozzles is caused by excessive needle valve hammering, due to excessive time in service, excessive needle lift or spring force.

Weak spring:- Causes of a weak spring are usually metal fatigue, due to an excessive number of operations.

Slack needle:- Slack needle is usually because of poor filtration of the fuel causing wear between the needle and body.

Over heating OR under cooling:- If cooling of the injector is reduced, either by fuel valve cooling system or poor heat transfer to the cylinder head, then the working temperature of the injector will rise. This can cause:-
– Softening of the needle and seat which increases the possibility of nozzle leakage and/or,
– Fuel to expand/boil out of the fuel sac, leading to carbon trumpet formation, and increased levels of HC and smoke in the exhaust gases.
Over penetration
If this over penetration is caused by prolonged low power operations

Poor atomization:- Poor atomization can be caused by low injection pressure (fuel pump wear), high fuel viscosity and nozzle hole obstruction such as carbon trumpets

Poor penetration:- Causes of poor penetration is reduced injection pressure, and nozzle hole blockage such as trumpets or sac deposits.

    Because of the repeated operation leads to weakening of springs, erosion and enlargement of atomization hole, wear of needle and nozzle seats etc causes the fuel valve leaky which may require immediate overhaul. 

How do you find Fuel valve require immediate overhaul (Indication)
> Drop in Power will be the first indication
> Darken the exhaust from the tunnel indicate improper combustion
> High Exhaust temperature compared to other unit
> Spark in exhaust tunnel
> RPM fluctuate
> JCW temp will increase

          Must Read:> Fuel Injector with Simple Diagram

Action
> If you suspected the fuel injector is leaky take out of Draw card which will show the fault in fuel injection. If confirmed, change the fuel injector or overhaul it
> If the excessive leak in emergency reduce load and cut off that particular unit.


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