Any advantage to 6.9 hard injection lines over 7.3 lines?

[Sjax]

I busted an injection line on my 7.3, and the junk yard sells them by the whole set. They have 6.9 and 7.3 sets.

I read that they should not be inter-mixed, because the 7.3 lines were a little shorter - due to an emissions issue.

Would there be any advantage to using all 6.9 lines on my 7.3 engine?

 

[gatorman21218]

I think they are all the same. the only difference is IIRC the number 3 line is different on the E-Series. You might want to look at e-bay. Did you remove the clamps? those are important. without them the lines will vibrate and crack.

 

[rhkcommander]

6.9 or 7.3, the lines are the same unless its from a van, then one of the lines is shorter because it is supposed to have a timing adapter on it. #4 i think. #1 might be too but IDK

The engines are the same virtually minus bore, head stud size, and minor differences. Return line size changes, 3/16" on most 6.9 and 1/4" most 7.3s. But that isn't important.

 

[Sjax]

Of course I can't find it now, but I have read in several places that the 7.3 lines are shorter (all 8 of them) due to an emissions issue, and that if you mix 6.9 and 7.3 hard lines your timing won't be accurate.

Perhaps that's opinion, rather than fact. But I thought I would ask the question and see if the answer was overwhelming one way or another.

I'll just stick with 7.3 lines.

Gatorman... I keep the dampening clamps on the lines - but I still appreciate the good advice (that's the reason I keep them on there). My line happens to be busted is because I torqued it down crooked and mangled the tip of the line.

 

[icanfixall]

The 7.3 lines are made 60 thousands shorter because the injectors were lifted up out of the heads by that much. This lift was for emmissions only. Try and buy in sets or like for like. But its not really something you will see at the hp or fuel mileage. Just might be tuff to make something fit easy. The vans have a differant number 1 & 4 hard line. The trucks have that silly rotunda timing adapter on them and the vans have it on number 4. Could you put all 8 6.9 lines on a 7.3 yes and it goes the other way too. Just remember to move the rotunda timing adapter from the truck lines to the van lines on these 1 & 4 cylinders. Make sure those vibration line clamps are in place or the pulses from the fuel pump will crack them at the injector nut. My number 2 let go there because I left off the clamps thinking I knew it all. That lesson cost me almost $400.00 at the dealer about 14 years ago.. Live and learn...

 

[Sjax]

Thanks guys,
just got back from the junk yard with a full set of 7.3 lines for $17. Hopefully they seal up nicely. Air/Fuel leaks = frustration!!

 

[hesutton]

$17!

Nice price!

Heath

 

[Sjax]

Still leaking!!
I've replaced o-rings (Viton), caps (from other non-leaking injector), and lines.

I can't stop this leak!!!

It's at the base of the plastic cap, not at the top of plastic cap or top of metal nut. It's a good leak too.

I'm gonna swap O-rings again, and then the whole injector.

 

[icanfixall]

It would be better to buy a return line kit and just do al of the returns at one time. I don't know how out the kit is on the engine now but if one leaks.... Well the others are not far behind. Its really tuff to remove one without disturbing any others. Some members just look at their systems and they leak. Someone was making a brass return line cap but that has not actually been talked about too much lately. Too bad because its a great idea. A small jewelers lathe and some silver soldiering and you have it.

 

[Sjax]

Oh I did do the whole set.

I put in all new stage one injectors (from DPS), an IP (from Pensacola), and a full return line kit (also from Pensacola). As a side note, Pensacola sent me the wrong return line kit. They sent the ones for the 6.9, but it didn't really matter, it wasn't hard to just route in front of the intake. I just hope they didn't send me the IP for a 6.9 since I have a 7.3 Turbo (which I clarified with them several times).

After I installed everything... the #4 line leaked - squirted actually.

I replaced the Pensacola O-Rings with Viton O-Rings...still squirted.

I then replaced the hard line since it appeared damaged at the tip. That stopped the squirting, but there was still a decent leak from the return line cap.

I swapped caps from another injector...still leaked.

I swapped lines/clamps...still leaked.

Tonight I'm gonna swap the whole injector (leaving the Viton O-rings in place) with the #2 injector (right next to it).

None of the others have given me any grief.

And yes... the hard line dampening clamps are one there.

 

[Wyreth]

Oh I did do the whole set.
I put in a new IP, all new stage one injectors, and a full return line kit from DPS. Which...they sent me the wrong kit. They sent the one for the 6.9, but it didn't really matter, it wasn't hard to just route in front of the intake.

I'm sure better minds can chime on on this, but I do not think that with the smaller return lines on the 6.9 kit are sufficient for how the later 7.3 return system was routed. The 6.9's had a separate run from the IP return, rather than routing it through the caps. You may just have too much volume for the caps/lines you have.

Some other things to check:

did you check the inside of your new return caps for burs? They commonly have them, (even the "high quality" kits) and they will slice up your o-rings when you install the cap.

another trick, install another o-ring on top of the return cap (I use one of the old ones for this) That will make the fuel line nut press the return cap down, and give you a better seal.

Also, pull the main return line in the back, and blow compressed air down it. You may have a plugged return line, and #4 &#2 are just the weakest seals.

 

[gatorman21218]

with every new kit ive installed, ive had to redo at least one cap and o-rings. i think they are just a finicky thing

 

[Sjax]

Thanks for the info Wyreth.
A couple things you mentioned are ideas that I have not heard or read about before... but they make sense. Especially about having a clogged return line - causing the weakest link to fail.

I will say this, and I hope others will share their experiences... The black return line caps I ordered from Pensacola are not as snug of a fit as the original Ford caps. One thing I tried was to put the original Ford cap back on. It was a tighter fit, but it still leaked.

 

[Sjax]

Update: I pulled the #2 and #4 injectors, cleaned them both, and swapped them.

For whatever reason... that stopped the leak.

After running the truck for about 10 minutes at idle, I noticed the #6 cap is just barely leaking...but enough that it bubbles after I shut the truck off.

And so the frustration continues, though it seems to be slowly getting better.

 

[icanfixall]

Sounds like you have a poor quality return line kit. There are several differant suppliers out there. This is a lesson learned by many. Both Mel and Russ sell a high quality kit. Nobody has ever hadan issue with them. If they did they didn't post about it. When I bought a set of BB codes from Russ I had several Ebay kits. So I used one.. Shortly I had some weaking. I watched this and finally got two kits from russ.... No more problems. Lesson learned and past on to others. The Hall of Shame is where the lessons are free for the reading. Ya see... Someone else had already made the mistake and paid for it so that gets written about in that forum. Really sorry for the problems your having but its fixable.