Help me understand injectors.

[skinner]

This is my first fuel injected engine i've rebuilt. When I put it back together it ran like a miracle...next day I got two injectors on the passenger side bank leaking between the rail and the injector it looks like...and BADLY. Before I go ripping back into it I want to buy the parts...
What holds the injectors into the rail? Is it an O-Ring? Am I lookin at trouble?
Thanks so much,
alex.

 

[skinner]

Anyone? Gonna start digging in the morning...don't wanna break anything.

 

[shadetree]

The injectors are held in place by the rail. The o-rings keep them from leaking. Leaks after teardowns are usually caused by the o-ring being damaged when put back together, or becoming stiff from being in the engine for a long while.

An o-ring kit at your local auto parts is cheap. When re-installing, lube the o-rings with something like Vaseline. Personally, I use silicone on anything rubber or neoprene that I am trying to slide into metal. With a little "slickem" they will pop back in place. Replace both top and bottom o-rings.shady

 

[evanesce69]

i know a little about the injectors. Yes, shady is right. The rail "keeps" the injectors in place while the o rings on either end seal it. The injectors actually floats inside the o rings freely. They are not mechanically secured to either the intake or the fuel rail.


All you have to do is replace the o rings (might as well get them all, cheap and easy to do)



oh.... an after thought... you may want to "ohm out" (check the resistance of) the injectors to see if any are on the verge of failure.

Again, it would be easy to fix any bad injectors/O rings while the top end is apart.

 

[skinner]

Thanks again guys! Yeah when I loosed the rail from the intake those two injectors basically fell out. The orings looked good, however.
My head gasket kit came with 6 injector rings. I wonder why when there are 12 orings? Since I didn't feel like taking the plenum off, I just replaced the top orings on the passenger side and the leak is gone...beautiful.
In the future, how do the bottom orings come off...do they have to be cut? They sit in there pretty deeply...and I wouldn't like the idea of prying on that plastic.

Thanks for your help, as always..
alex

 

[Wicked_Sludge]

a mechanics pick or small flat tip screwdriver will make short work of stretching the o-rings out of the groove and over the injector tip.

 

[evanesce69]

ditto

 

[almostclueless]

One oring seals between the rail and injector, one seals between the intake and injector. Both are important.


New orings probably should fit snugly as the injectors are pushed into the intake and rails.