Fuel Injector Question
 

Looking for opinions anyone think this injector was leaking cylinder compress on that cylinder.
Pintel cap was missing on removal but oring was found in manifold. Engine was low on power checked plugs wires fuel pressure reg for paint all good. Compression test is next once injectors are back. Rethinking maybe I had a compression leak in the number 4 cylinder where the Pintel cap was missing and maybe leaking thru that o-ring.


"Your set of eight Delphi injectors flow tested 'okay' right out
of the box ( after an initial exterior cleaning / de-greasing ), and
flow tested at about a 5 % flow balance ( 78 to 82 cc ). An 5 % flow
balance is not great for a used set of injectors, should be a little
better. Spray patterns were normal in all of the injectors. All of the
injectors held pressure ( no leaks ).
The engine would have run okay with these injectors, maybe a tiny
bit rough.
Will have them in the ultrasonic tank and finished tomorrow
morning. Should get a little better after cleaning."

First pic showing cylinder blowby
second pic is what all other injectors looked like.
Never heard anything noise wise but twin 496s and hatch was not open at cruise.
looking for thoughts.

Sorry cant post pics yet

just do a count down.... each post one number.... 7, 6, 5, etc till you hit 10 posts and then post the pics.

11

https://cimg5.ibsrv.net/gimg/www.off...8547c07479.jpg
https://cimg6.ibsrv.net/gimg/www.off...5f4f49a9d4.jpg

Since these injectors spray into the intake manifold, not the combustion chamber, you can't leak compression past them / the o-rings. If there's a leaky intake valve, you could get compression and combustion gases on the tip of the injector but the path of least resistance will be back into the intake manifold, not past the o-ring.

If you have low compression it's not because of an injector not sealing well.

Id also do an oil analysis...its possible the injector was leaking....fuel running down the runner and past an open intake valve and collecting in the cyl.....eventually seeping past the piston rings and into oil....could wash the cyl wall clean and if there's moisture from an open intake or exhaust valve you could have corrosion on cyl wall causing lower compression too...
highly doubt it unless it sits for long periods of time but it could happen if the stars align just right :)

unless your engine is direct injected, your injectors are not subject to cylinder compression pressure

The injector port is in the manifold couldn't it be leaking air into the intake manifold the engine ran good except at wot only got to 4400 rpm and seamed to lack power other engine (also needed more throttle at cruise) to 5000 rpm and strong.
Engine used more fuel so I agree with you I'm NOT saying it was leaking at valve BUT intake port past oring on injector to the outside of the manifold it could leak both ways depending on the engine rpm ect. what ever was leaked would not have shown up on the map sensor pressure.

Unless you have a turbocharger or supercharger, there's never going to be positive pressure in the intake manifold (aside from the slim possibility of a very leaky intake valve, and even that would probably not cause positive pressure of any significance). A leaky o-ring where the injector goes into the intake manifold, could cause outside air to get past, this is a vacuum leak, and could cause issues such as rough running.