#4 injector line leaking

[Smoke Eater]

There's always something else to fix. While I had my transmission out, I decided to replace the rear main seal. It's had a slight leak for a little while, may as well get it done. Installed the new seal with little trouble, nice... not! I started it up to make sure it wasn't leaking and found fuel leaking instead. Traced it back to #4 injector line, slight dribble at the feed tube connection. Bought a new one from Cummins, installed it, still dribbles. I'm figuring the feed tube is the problem. Any other ideas?

 

[Darkbloodmon]

Can you get pics? You could try re torqueing the connector tube nuts. Make sure the hard line is properly mated to the surface. I spent hours tweaking and bending my CP3 too Rail supply hardline when I replaced the CP3 with a 6.7 Super Sport from S&S Diesel. if you're working on the shelf and opening things up I recommend power washing and degreasing it first; cleaner area to work and easier to detect leaks.

 

[Smoke Eater]

Makes sense, I may not have had as good a grip on that nut as I thought I did. Wouldn't take much to loosen it up.
Thanks

 

[Darkbloodmon]

Makes sense, I may not have had as good a grip on that nut as I thought I did. Wouldn't take much to loosen it up.
Thanks

No problem, keep us posted.

 

[Smoke Eater]

Ordered a new injector tube. It wasn't even close to being the same as my old ones. Went through my stock of old parts and found my original tubes I'd pulled when I installed the new injectors. I took an o-ring off one and replaced the leaking one. No more leak.

 

[Ozymandias]

You know that the tubes have been updated with a improved design some years ago.

 

[Smoke Eater]

The new one is on the left, the one on the right is one I replaced when I put in new injectors about 5 years ago. The new one is. 040 longer

 

[Smoke Eater]

 

[AH64ID]

If you look at the distance from the seat to the tip they appear the same, and the extra length is on the connection side.

 

[Smoke Eater]

They are the same from the seat to the tip.
The opening at the tip is. 075 on the old one, and .115 on the new one. I wasn't sure if that would cause a problem.

 

[AH64ID]

They are the same from the seat to the tip.
The opening at the tip is. 075 on the old one, and .115 on the new one. I wasn't sure if that would cause a problem.

They are universal 6.7/5.9 now. The 6.7 got higher flow tubes which are backwards compatible.

 

[Smoke Eater]

Would that make a difference having one 6.7 tube and the rest being 5.9 tubes?

 

[Ozymandias]

Would that make a difference having one 6.7 tube and the rest being 5.9 tubes?

No because the pressure is equal throughout the rail and the tube is part of it.

 

[Smoke Eater]

Sounds good, I'll just keep it as a spare then.
Thanks

 

[cerberusiam]

The larger tubes are 6.7 designed components for the higher pressures and flows in the 6.7 system. The 5.9 tubes are still manufactured and can be easily obtained if needed.

Pressure may be the same but the flow thru to the injector is going to be higher. The ECM tracks fuel usage basically by flow so there is a possibly a mismatched tube could introduce an imbalance. All things being equal, the ECM should be able to adjust for differences. If it doesn't you could end up with some imbalance. If the imbalance is off far enough it could surface as vibration. Considering the crappy OE balance job on the rotating assembly and the less than adequate injector balance on OE injectors anything is possible.

 

[Smoke Eater]

Resurrecting an old thread. Recently I started seeing more fuel leaking again. This time from #2 and #5. Decided to replace the o-rings on the connector tubes, don't recall which brand these are, but this is a problem. Looks like the old o-ring is falling apart, kind of brittle. I'll post a picture later, need to resize them. I'm installing new Cummins o-rings now, part #4062328

 

[Smoke Eater]

This is the o-ring on the 5 year old connector tubes, the originals that came out when I installed the new injectors looked nearly new. I was sure to use lube when I installed them.