so im in the process of attempting to replace my injectors, i got the plenum off and now i found this. only one of the holes has this black crap in it. im assuming oil

anyone can confirm this and know where its probably coming from?

 

i also just took out the spark plug from there and its like black. no gunk or anything just dry black.

 

Looks like oil to me

I would replace the intake manifold gaskets while you have it torn down, it might be blowing oil between the intake manifold and the head.

If you decide to do this, you will see right away when you pull the intake gaskets whether or not they were leaking.

 

Also looks like it may have been running rich and depositing a lot of soot in there too. EGR and PCV may need a look too.

 

yeah i can guarantee it was running rich hence the whole injector project. kid who owned it before thought it would benefit putting 17lb injectors in. so ill have to check that other stuff while im at it. might as well. i have all winter so ill replace whatever i can. thanks guys. i just needed somewhere to start looking.

i really appreciate all the help everyone here is really helpful.

 

my highschool teacher also told me to get the intake parts and stuff hot tanked while im at it

 

That's above the injectors so it has nothing to do with being rich. It's a combination of PCV vapors, EGR gasses and dust/dirt that makes it past the air cleaner. Turns into a sticky carbon mess that cakes onto the entire intake tract behind the throttle plate(s). For a daily driver, no big deal- lose a little performance but things still work fine. For performance applications- clean it out.

That's a V6 but V8 TPIs with miles sometimes have similar problems.

 

so its not oil just the gunky build up?

 

Yup, have to agree with Damon and hence the reason I do not run a EGR system and on my newer cars limit the flow rate.
GM and others do not use a progressive rate system, just a one size fits all and just off throttle tipin, EGR is at max flow and after a cold start with moisture in the exhaust, this gummy mess ends up in the top half of the motor.
Still needs to be cleaned up and recommended that if you plan to use a EGR system a yearly cleaning is done. One can of spray, Gum Out to be used while its running sprayed right into a throttle body or carb, then one can of sea foam sucked through a PCV line to clean the valves and cylinders.

 

Mc305ss and Damon,
Did you notice how shiny and wet the front port is?
I know the black crap in the ports is from PCV/EGR, but the front port is also shiny and wet from what looks like oil...

 

That's what I'm talking about only that front port is like that. None of the other ones. I know oil isn't getting in the cylinders as there's no oil on the spark plugs so it doesn't look like it's burning oil. It's just on the top off the engine in that one port out of 6.

Also what could I run through this now to clean it like what's safe to use while I have it off. Or should I just go get the parts hot tanked.

 

Getting oil up that high MIGHT indicate the PCV system isn't working right (PCV valve and related hose) and the vapors are backing up through the fresh air tube (instead of going through the right way). They design it to do that in the event of a PCV system failure, but the downside is you get a lot of oil vapors passing through the upper part of the intake.

 

If it was the PCV, wouldn't ALL of the ports have oil in them?

 

UPDATE:
okay heres and update and it sucks. pretty much it just means tearing it down more and just running through things. i FINALLY got to the injectors and it really wasnt hard to take out at all. BUT there was a surprise. previous owner (friend of mine) had no idea what he was talking about and the "17lb injectors" that wer in there ARENT. ofcourse there the normal 15lbs. so now i gotta find out why my car is ether running really which or if its running really lean causing it to run rich :X AND i gotta find out why its having idle issues and start issues. it doesnt always wunna start the first time, i thought cus it was flooded but guess not...

oh and heres some pics of where the oil is now. thats the intake manifold and the bottom of the lower intake. deff leaking oil through that gasket and it kinda looks like the manifold gasket might be leaking like that too. BUT i really dont think im getting oil in the cylinders cus my car doesnt smoke or smell like burning oil or anything like that? is it possible shes just leaking oil in those places? there was some oil on the tips of the injectors to it looked like. couldnt be to good for the car

 

anyone got any ideas?