Injectors

[AussieISX]

Had o go at repairing a leaking injector I had in number six cylinder today . I've had a fuel knock in six for a short time which I believed was a remnant from air cavitation. Last two years I've replaced all six injectors so all are fairly new . Number 4 caused a lot of problems until I realised I had air in the fuel. Did a leak test across both metering accuators to find number six making air . Stripped the injector and found a lot of carbon build up at the tip of the plunger and the tapered seat area where it clearly wasn't seating and sealing combustion gas . I used some carb cleaner and a tiny wad of polishing grade steel wool down the tip of the injector to remove all the carbon. The plunger was easy enough to clean and polish up . I then used aluminium polish and pushed the plunger back into the tip , spinning the plunger in the tip with alloy polish in there to lap the taper . After a very thorough clean of all parts I put it back together. So far so good. With the injector reinstalled the knock has gone and so have the bubbles in a follow up leak test . I believe the cavitation allowed the plunger to bounce off the seat in the tip providing opportunity for carbon to pass . Once anything contaminated the tapered seat it was all down hill . Hopefully it continues to seat and another injector won't be necessary