Finally got around to testing, and then replacing the glow plugs.. 4 stuck.

MJGenay said:

I have a soldering iron on order from Amazon... seemed well reviewed and less than $20. If those I crimped last night hold up I am going to just crimp new fuse links into those wires as well, if they don't it all comes apart and all gets soldered.

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IDIBRONCO said:

The above describes fuel drain back, not air intrusion. Air intrusion only happens when the engine is running and it affects the way that it runs.

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franklin2 said:

This is a change in terms that I haven't heard before. Although this is all made up on the internet boards, most people say "air intrusion" in reference to the o-rings leaking around the injectors. So that would be the "fuel drain back" you are talking about. Before, if the pump was sucking air, that was also called "air intrusion", thus you always had to ask what the symptoms are to discern which problem the truck has.

If you want to separate the terms and call the two different situations two different terms, I would welcome that, but this is the first time I have heard of the change. Even then, anyone posting about their truck having a problem, the poster will still need to be drilled to find out the exact symptoms.

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IDIBRONCO said:

Oh I know, but those who mix up the two are wrong. The names are the definitions. Fuel drain back should be obvious. The fuel drains back toward the tank. Air intrusion is more difficult. Basically, air intrudes into your supply side of the fuel system. Air does get in AFTER fuel drain back happens, but ONLY because the fuel drains away and is no longer there to keep the air out. Another way to think about this. Most (not all) of your fuel system is actually under a very slight vacuum when the engine is not running. If it wasn't all of the fuel would drain back from the highest part of the fuel system (engine area) to the lowest part (fuel tank). The slight vacuum holds the fuel in place. When the system is no longer sealed, the vacuum is released and the fuel runs away from the engine-drain back.
The confusion comes people not realizing why the symptoms are happening. As I said before, the two problems can be related, but are totally separate issues. That goes back to the location of the leak. Supply side (while running) is intrusion. Drain back can happen on either side of the injector pump.

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hacked89 said:

X2 air intrusion is supply side

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MJGenay said:

Okay well after reading all of that I have no idea what my issue is I have a crank of a few seconds (1-5) when it hasn't been run in a day or more, then she'll fire up. A few seconds later she starts rattling all to hell, sounding like a misfire or I don't know what. I kinda assumed that was air getting in by my o rings on the return side, which I mislabeled as "air intrusion". It goes away after a couple minutes but it has been getting progressively worse over the past few months.

To be clear this rattling or misfiring or whatever happens intermittently over those couple minutes. Used to be if I bumped the pedal it went away for a bit. That doesn't seem to happen as much anymore.

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The_Josh_Bear said:

Best way to upload a video is to host it on YouTube and then link it here.

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franklin2 said:

Sounds to me like you might have a very minor drain back problem. So minor it doesn't stall, but the little bit of air you do have is causing the noise.

After that, it doesn't do it the rest of the day it from what you are saying. If you let it set for a week or 2 before starting, I bet you will get a stall as more and more air gets in. If you want to try an experiment, and have the terrain to do it, if you park the truck with the rearend up hill as much as you can, then see if the problem goes away. If you get the tank elevated, the fuel will have less tendency to "drain back" to the tank.

As far as permanently fixing it, it might be difficult. You have a tiny leak somewhere. You need to take a flashlight and carefully inspect all the return caps on the injectors. Any bit of dampness with dirt sticking to it will be the culprit. If you can't tell, spray it down with brake cleaner to clean it off and then keep an eye on it.

Another common place to look is the fuel heater on top of the fuel filter assembly. Any slight oily dampness will be a problem. There is a couple of youtube videos on how to change the o-ring on the heater, that worked for me for a couple of years and then it started leaking very slightly again. So I read of a guy on here just packing jb weld around the heater fitting so I did that and have not had problem since.

Also inspect all of your rubber lines. I had one that came off the injection pump and ran over to the return system, and it was a little damp around one of the clamps. Had to redo that one also.

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MJGenay said:

Alright, working on that now. The rattling and all wasn't bad at all last night when I took the video, that is probably because I had driven it a few hours prior.

Okay, makes sense. I believe I have slight dampness around 3 of the return caps. It's probably worse since I was laying on the engine replacing the glow plugs. PO replaced all return caps, o rings, and return fuel lines. I'm hoping I only have a issue with the o rings but we'll see. Should be able to knock that out this morning.

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franklin2 said:

That dampness is probably your problem. If the o-rings are not that old, you can sometimes grab the cap and with the little bit of play allowed by the rubber hose, twist the cap back and forth as much as it will go and sometimes they will seal back up.

I had this same problem, I bought Buna-N o-rings from tractor supply. They lasted a couple of years and started weeping like yours. I changed them again and the same thing happened. I finally went with the viton o-rings you can get a McMaster Carr, and they have been on there for years now with no more leaks. I never have bought a kit, I still have my original international caps with new hose I got from Napa and the o-rings I got from McMaster Carr.

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