The hunt for air begins...

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
So I got her started, and now the sputtering is more pronounced, and lasts longer... Drove about an hour total going to a friends and getting fuel. Let her cool for an hour, and started again. Started up first crank, sputtered for about 15-20 sec. Seems like whatever air is getting in there, it's happening more now than right after I did the return line kit... Only touched connections around the filter since then, so maybe I messed with something.

The front line going into the filter from the supply pump seems to have play in it at the top, even when the brass fitting is as cranked as far as it will allow...
That's where I think the air is getting in.

I'll try to post a picture.
 

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
You must be registered for see images attach

You must be registered for see images attach


When I opened that line (had play in the top fitting before I disconnected it...), it was dry. After every crank there was a little air 'pssst' from the filter bleed... Then I tried the block warmer for a bit. Batteries seemed to be slowing a bit by then, so despite the warm block, no start... The block heater increased the "pssst" from the filter. I thought that might be a clue? I think the air was keeping a pump that was running on low battery from getting the fuel there though, because when I hooked it up to a ford ranger, the boost was enough to really get that pump going, and it fired up.

That was the first time I started it, so idled for 30 min... Shut down. 45 min after that, drove an hour fine. One start after 1 hour sitting, and nothing since...

Think I'll go out at bout 3 AM to see... Got the block heater on...

Also... Could I use sealant on that line if that's where the leak is?
 
Last edited:

icanfixall

Official GMM hand model
Joined
Apr 10, 2005
Posts
25,858
Reaction score
682
Location
West coast
That lift pump line to the filter head is where you need to replace the rubber olive. Its a 3/8 inch line so the olive is the same size. Also change the filter feed to the injection pump olives. Thats a 5/16 line ans so are the olives. Make sure the olive is pushed back on the flaired line so the line enters the female end of that brass fitting for support. Any good injection pump repair shop will have these olives.
 

riotwarrior

Full Access Member
Joined
Sep 19, 2006
Posts
14,782
Reaction score
492
Location
Cawston BC. Canada
Nope no sealant...use the olives and O rings per what has been said here.

Bottom line...

Go through the list I made up and determine what needs replacement.

Also clear lines as Agnem (Mel) said to determine air movement.

Gitterdun!

Al
 

Defrocked

Full Access Member
Joined
Nov 4, 2013
Posts
89
Reaction score
0
Location
SoCal
So there are only 3 olives in the 7.3 and all near the filter head?
Where can I get these??Mel maybe??
 

Wyreth

Certifiable Noob
Joined
Aug 6, 2011
Posts
845
Reaction score
5
Location
Las Vegas, Nv
So there are only 3 olives in the 7.3 and all near the filter head?
Where can I get these??Mel maybe??

Correct. The early style return system on the 6.9's has a dedicated return line from the IP that attaches to a 4way union, for IP return and right/left bank injector return, at the back of the engine. That attachment point is where the mysterious 4th olive is located. On the later style return, the IP dumps directly into the injector return cap on the #2 injector, rather than using the 4way union. The picture on the previous page shows the early return style with the 4way union.

As to where to get them? I get mine from Type4, Mel has them too.
 

Agnem

Using the Force!
Joined
Jan 10, 2005
Posts
17,067
Reaction score
385
Location
Delta, PA
If your fuel supply line olive at the filter head were leaking, you would loose prime in the line, but the filter would remain full. Next time it sits, before you try to start it, unscrew the filter. If fuel spills out, it's full and your air leak may be at that olive. If the filter is NOT full, then the olive held, and fuel was sucked out of the filter back towards the lift pump by gravity. Your air leak is in the filter head, head to IP line, or any part of the injector return system.
 

N.E fjord-by-fjord 2fiddy

Full Access Member
Joined
Nov 22, 2013
Posts
210
Reaction score
1
Location
Maine
Update: i picked up some "olives" from a diesel shop off an old 6.9... Guy gave em to me for free, and they were still soft and bouncy... Thing is, he said they were both 5/16.... I'm wondering if the filter head on 6.9's was 5/16 in and out, even though 7.3's filter head is 3/8 in, 5/16 out... Or did this guy give me both the olives from the filter side and the pump side of the hard line from the filter out to the injector pump? Either way... While putting on the filter side olive on that line, I moved the line... I think this started letting in air @ the injector pump supply line's olive... Because now it starts (with the usual blub-blub and blue smoke of the slow leak...) AND when I bring the revs up to almost 3000, it starts coughing and letting out puffs of blue... This to me says that the injector pump, when running harder at more rpm's, is sucking air in @ it's supply line olive, when at idle it wouldn't....

Does this sound right, or am I way off?
 

Agnem

Using the Force!
Joined
Jan 10, 2005
Posts
17,067
Reaction score
385
Location
Delta, PA
The lift pump should be supplying more fuel than the pump will use just sitting still. He gave you the olives off the IP to filter head line. You need a 3/8 on the filter inlet side. You could get one of my Moose Feed Lines and end your olive hell from pump to filter. Not that it will solve your problem, since we still don't know what your problem is.
 

Defrocked

Full Access Member
Joined
Nov 4, 2013
Posts
89
Reaction score
0
Location
SoCal
So if I'm replacing the hard line from lift pump to filter head with a rubber fuel line I will be elimiminating one olive,correct?
 

Defrocked

Full Access Member
Joined
Nov 4, 2013
Posts
89
Reaction score
0
Location
SoCal
Also the hard line going from filter head to IP can I also replace with rubber hose,I assume its not high pressure.?
 

chris142

Full Access Member
Joined
Apr 15, 2012
Posts
3,007
Reaction score
354
Location
SoCal
I would not use rubber hose between the filter and the pump. Often Rubber hose has small bits of rubber break off and you dont that getting in your pump
 

Defrocked

Full Access Member
Joined
Nov 4, 2013
Posts
89
Reaction score
0
Location
SoCal
Any tricks on removing a hard dried up olive from hard line nut,its stuck at the bottom of the threaded nut on both ends.I sprayed it with some break cleaner and it helped a bit to loosen the nut but olive is stuck in threads.Maybe a little heat?
 

Forum statistics

Threads
92,996
Posts
1,155,953
Members
26,579
Latest member
truckonfire

Members online

No members online now.
Top