Faulty Injector - Clues

[nacelp]

> I removed a plug with light brown coating all over, and a dark spot on one
> third of the tip of the electrode ceramic.

That's way I index plugs, to avoid this kinda nonsense.

  It appeard this burn (or oil
> deposit) spot is taking on material coming either from the direction of
the
> piston, or from the direction of the valve (angleplug alum heads), I cant
> tell where it faces when screwed all the way in.

So turbulent in chamber can be from anywhere and just centrifigal actions.
>
> On previous inspection of this plug, a yellow coating was noted, and a
part
> of the ceramic tip was chipped off, like it had blistered. I went one plug
> colder and now this burn spot, which is shiney and thin (wont flake off,
> just turned the ceramic dark)

Look at glazing, for the yellow.
Second part is misleading try again.
>
> I looked at several diagnosis pictures, can't come up with one that
matches.
> The closest one makes the injector suspect.

??. Suspect how rich or lean?.  Need better description
>
> The engine gets rather severe duty =(my foot), 383CI, 9.8:1, TPI, alum
heads
> and pistons.
> The injector ohms fine, and fires with 12v.  GM manual says connect
injector
> test part # xxxxxx... Is this injector tester cheap and available??

Must be an old part number, most all nowadays are xxxxxxx, or xxxxxxxx
I tried the xxxxxxx, and never have gotten anything
Grumpy
> TIA.


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