6.9 idi injector return cap leaks

[Cole_Sudeyko]

Got an 86’ 6.9 and I’m fighting leaking injector return caps and air intrusion. Cannot for the life of me find a straight answer on the proper o-ring size for them, I’ve ordered two different kits and used two used sets and everything has leaked or hasn’t fit, I now have a brand new set of Delphi caps and o rings, the rings that came in that kit are a -111 but I’ve read that that’s wrong and that the correct size is a -011 so I tried that and the cap just fell on(way too small) so does anyone have a straight forward answer as to what’s going on here?
Water separator is bypassed as well.
Any help is appreciated thanks!
UPDATE!!
The Delphi kit with -111 orings fixed all but 1 cap so I’m thinking I probably nicked the o ring on that 1. Vaseline seemed to work way better!

 

[Indadesert]

So if you have the right prongs from a reputable supplier of Idi parts then it’s the caps or injectors. Some people buy them from granger I think those are the 111 size? But I usually just buy a whole kit every few years and an extra set of o rings. Never once had a leak. I’d bet you have something else going on.

 

[IDIBRONCO]

The size is a 111.Sometimes, new caps are made with too big of an internal diameter. If you still have the old caps, try using those to see if that helps.

 

[Cole_Sudeyko]

I’ve tried two sets of original caps with -111 and those both leaked, so I took a gamble with an Amazon kit with low expectations and as you can imagine that leaked too but I read good things about the Delphi kit that rock auto sells so I ordered it just have yet to try it

 

[hce]

Are the caps pressed down all the way? There should be a gap between the injector line nut and the cap. Are you greasing up the caps?

 

[Cole_Sudeyko]

Yes caps were lubed and there was a gap between the injection line nut and the top of the cap, close to 1/8” I’d say maybe a bit less

 

[hce]

The only other thing I can think of is make sure they are buna n or viton with a durameter of 70-75.
9464K24 is the mcmasters number from the parts bin Noticed the parts bin is a bit tougher to find, thought at one time it was sticky-ed.

 

[hce]

Check the o-ring sealing surface of your injectors make sure they are clean, rust free and without defects.

 

[Indadesert]

Stop tossing parts at things and figure out what’s wrong

 

[Kdo58]

xc_hide_links_from_guests_guests_error_hide_media

Watch this and buy these, upgrade to 7.3 caps and hose.

You must be registered for see images attach

 

[miked]

Check the o-ring sealing surface of your injectors make sure they are clean, rust free and without defects.

I second this, if multiple caps have been tried and still leaking it may be the problem,
some fine emery cloth, applied carefully!! Has saved a surface or two for me in the past.

Stop tossing parts at things and figure out what’s wrong

I am just starting to tear my truck apart for the winter again and have started reading posts again.

I was hoping the unhelpful posts like this had permanently disappeared.

Every once in a while, some positive knowledge comes from this source, which leads me to believe he could be a helpful member of this community.

 

[Cole_Sudeyko]

Stop tossing parts at things and figure out what’s wrong

Hence why I’m here thanks‍

 

[Cole_Sudeyko]

I second this, if multiple caps have been tried and still leaking it may be the problem,
some fine emery cloth, applied carefully!! Has saved a surface or two for me in the past.


I am just starting to tear my truck apart for the winter again and have started reading posts again.

I was hoping the unhelpful posts like this had permanently disappeared.

Every once in a while, some positive knowledge comes from this source, which leads me to believe he could be a helpful member of this community.

Thank you!

 

[Cole_Sudeyko]

xc_hide_links_from_guests_guests_error_hide_media

Watch this and buy these, upgrade to 7.3 caps and hose.

You must be registered for see images attach

What’s different about the 7.3 caps compared to the 6.9?

 

[Nero]

Just a different co figuration of caps. Tees and elbows in different spots. Same diameters for O rings.

What are you lubcricating your o rings with? I will either buy a harbor freight box of misc o rings, or get a set from a vendor, and I lube them up with a glob of vaseline. Rarely have one leak.