So I've been having trouble starting the truck after sitting over night for quite a while. Since I found that fuel filter is half full in the morning, I knew that I have a common problem with air intrusion most likely through fuel return system. I bought a kit on Amazon which came from Pensacola and installed it. Also installed a Facet Duralift pump at about the same time. There was some improvement, but not much as batteries were going south already, so these were changed too. Still not much of improvement though. Next was the new set of Beru ZD29 glow plugs. However, the plugs I pulled were looking good and were Beru ZD9. I lived with tat problem for a while as I don't use truck every day, but recently decided to find what the problem is and fix it. Two thins made me believe that air intrusion is still my problem. First because I was pretty sure that glow plugs and relay are working properly including afterglow. Second thing was that I didn't see anything coming out of the exhaust while cranking.
So the first thing first. I replaced the fuel line between the Facet pump and the filter with a piece of clear tube, primed the system, ran the engine for a few minutes and let it sit overnight. Popped up the hood next morning and I saw this:



Pulled fuel filter and sure enough, it was half empty. I have independent switch for the pump so I can run it with key off. Ran the pump for a couple of minutes and went to cranking. Won't fire, outside is about 40F. Then I thought well, with key off my fuel shut off solenoid is probably blocking the path to the IP and it still could be empty. Turned the key on, ran the pump for a while, got in the truck, cycled the key off/on to get the glow plugs on and she fired right up.
So yes, air intrusion, but where? I was still confident about fuel return lines, caps and o-rings so started looking around. Fuel filter housing and the bracket have been covered with fuel which I have seen before, but ignored it. First thing I found was air bubbles coming from under the schrader valve cover while engine was running. Replaced it, cleaned everything around and kept looking. Pulled the plug off the fuel restriction sensor, or whatever it is, to clean it up and found air bubbles coming out of it. This was getting interesting, so I started the engine and was looking at that thing. What I saw was fuel coming out of it and dripping at the rate at about 1 drop per second.



Pulled the thing out, cleaned with compressed air and put it back in. I wanted at that time to replace the fuel return line which goes from filter to #1 injector with a piece of clear one, but didn't have any of 1/4" tubing on hand. This is a small leak that I don't believe would be my main problem, but who knows. And now I started to lose my confidence in fuel return kit I have installed earlier. Had to go about another business and let the whole thing sit until next morning which was today.
Same 40F this morning. Ran the pump for 5 min with key on, cycled key off/on, waited until "wait to start" light goes off, cranked it over and she fired right up.
Have I screwed up the installation of Pensacola kit? Not likely, but who knows, so I am ordering new sensor and a new Delphi fuel return kit tonight. Will post more after I am done with it.

 

delete the filter to #1 injector line. there was a TSB from ford back in 89 or 90 to do that to help prevent filter drain back due to air intrusion.
what ford found was the one way valve in the filter head the line from the injector goes to is not as good as it is supposed to be. it had been disconnected on my 88 for around 425,000 miles with no issues at all.
when i first did it, i took the line off the filter head and put a bolt in the line with a hose clamp to keep it tight. then removed the valve and put a brass line cap in its place. when i needed a return line kit around 100,000 miles later i just used a single outlet cap on #1 injector.

 

Why isn't the truck firing right up on the fuel still in the hard lines and the injector pump, and then stalling out due to the fuel drain back issue though? That's what I would be wondering equally as much. It should still be a nice, easy quick start and short run on that.

 

I was wondering too, but thought about it that way: engine stalls as soon as FSS is deenergized, and there is a standard procedure of purging air out of the system after replacing fuel filter.

 

So here is continuation.
I didn't remove return line from fuel filter head to #1 injector as Tom suggested but replaced it with a piece of clear tubing instead and replaced leaking fuel restriction sensor.
After sitting overnight there was air in supply line and return line was empty. Ran e-pump for a while and got it running. With engine running was observing the return line. I saw fuel flowing but it still stayed empty. Drove the truck about 3 miles, stopped to check return line and it still wasn't full. After another 5 miles or so around the neighborhood it finally got full.
Since I found a faulty FSV on my other truck I thought that I may have a problem here too. I've been using the truck with single tank for 5 years and didn't feel like I need the second tank, so I pulled FSV, cut back rusty portions of steel fuel lines and ran 1/4" hoses straight to the tank.
Primed, bled the injectors, got her running and noticed some difference.
1. Return fuel line got filled before even engine warmed up.
2. This was the most interesting. I was complaining a while back here that my engine sounds like a tin can full of loose bolts and nuts which kept bothering me especially that I have another truck right here which runs nice and quiet. So, to my big surprise, there was no more of that nasty clanking noise. It was running as diesel supposed to and was quiet to the point that I heard my exhaust standing in front of truck with hood open.
Shut it off and let sitting until this morning. It was around 30*. Again, air in the supply line and empty return line. Primed, cranked and she fired up on the first try which never happened before at 30* without plugging block heater.
Well, air intrusion still there. Shut the engine off and noticed that air showed up right away in the supply line.



Now I am puzzled. Filter is tight, leaking schrader valve replaced, leaking fuel restriction sensor replaced, no leaks around fuel heater connector, no air in return line, checked tank vent and it's good. The only thing remaining is supply line from filter head to IP and the fitting on filter head is slightly wet. So what do you think guys? Where this much of air is getting from into supply line right after engine shuts off?

 

Cleaner supply of fuel, took away extra rattling in the engine? "The fitting on filter head is slightly wet." Which one?

 

This is how you fix (or pre-fix) that useless heater:
I jb welded in this one, because they said since it wasn't brass, it could turn out. I used a brass one in the other truck, after. I can attest, both methods work.

 

My last suspect was the fuel supply line from filter to IP. Fitting on filter head for this line was slightly wet, but I am not sure whether it's leaking or there was still some residue left from leaking fuel restriction sensor when fuel was all over the place being pushed by the fan. I cleaned it up real well and will see if it stays clean and dry. But even if it's leaking, I don't think it will allow this much air into the system the moment I shut off the engine.
I didn't know there is a check valve on return orifice, so now it's clear enough that air is getting from somewhere on the filter head, not from return system. I read that people replace that steel fuel line to IP with flexible hose and there are kits available somewhere. Does it make sense to bother and what's in the kit?
I will look into fuel heater later in greater details. Got to run now.

I just popped up the hood and see that there is still the same amount of air in the supply line as it was yesterday.

 

Oh yeah. There are seals in those lines that eventually dry out. I just ditched those recently on both of my trucks. I forget which truck it was that had the "olive" as most people call them on the forums, crack and leak, but I upgraded both trucks at the same time, while I was fitting up the parts for one truck, I just got two of each fitting. I went to the Parker store and got the fittings. I didn't note any part fitting #'s though. Dang. Yes. It's worth doing. All you need is the fitting that screws into the back of the IP, turn into a 90, then the other fitting, to turn that end that points up, into a fuel hose barb, then you can run rubber hose over. Now there's no more "olives" to be bothered with in my system.

 

I am trying to understand the physics behind all this focusing on the air in the supply line and leaving return lines along for now as the only thing which was not replaced there is a portion of return line going from the fitting on the back of the engine to the to the point where I cut the original steel line just behind trans crossmember.
So I played a little more today. Shut off the engine and left e-pump running, then shut off the pump. Air immediately showed up at the top of the supply line at the filter head. Pulled the filter and it was about 1/4" from being full. That is a pretty good deal of air in a split second. Isn't it because of no more pressure applied by the e-pump? It's impossible that any small leak in the filter head will allow this much air right away. And return line from filter head to #1 injector is full of fuel with no signs of air, so check valve is good.
Then I wanted to see what's going on with this on the other truck. Shut off the engine, shut off the pump and got air the same way. However, about half as much. It was going dark already, so I didn't pull the filter there.
So the big question is: Maybe it's normal? Both trucks share the same setup with Facet pumps and lift pumps removed. The other truck starts right up even with old batteries which won't turn starter at all after 10 sec of cranking.

BTW Is it worth paying $140 for this: High Performance Ford or Chevrolet Moose Fuel Feed Line $140.00 – Moose Diesel LLC

 

Well, rubber rated diesel line lasts a very long time and it's of course much lower cost. If that little section of hose breaks down in 15-20 years, it's not really a chore to replace it. That's a nice dress up item, for those into that. For work trucks like ours.......not so important to us. I will say though, though I don't recall what those Parker fittings cost now, they were not inexpensive either. I don't think the close to that for both trucks even.....but it's been a couple years now. I wonder if you find the parker # by searching. I just took the fitting off the back of the IP and took it to the Parker store and told him what I wanted to do. He did have to order them and I to back to get them. It was that 90 degree that was the pricier of the two of course. Just a adapter to barb from that.
Shame on me not putting the part #'s in my records. In fact, I missed putting the upgrade was done at all in them. I'll have to figure it out now or it will bug me haha.



OK Maybe:
Parker 75826; Swivel Elbow Fitting 90 Degree; 1/2NPT
Looks just like that. It's the swivel style so you can get it down in there and snug it up while keeping it straight up. Searching on here, they're saying (here) the rear thread is 1/2 NPT so I guess that must be that.
The 1/2npt to barb should be easy now......
Well any of them work I guess, but I got the "push on" style where you don't even need a hose clamp, though I use one anyway.
Hose Barb to NPT Female (Brass) 1/2" Push-on Barbe to 3/8" - Is this right? Did I use 3/8 hose here? ....Think so.
So maybe like like one;
Push-On Hose Fitting: Hose Barb x NPTF, 1/2 in x 3/8 in Fitting Size, Male x Female, Rigid, Straight - PB-NPF-0806
I wasn't picky about my hose barb style haha. It's just they had those on hand is all. 1/2 npt female to hose barb anyway.
I'll look to see what I did for sure to hose size and add these to my records if this is right.

Then some hose and Bobs your uncle. Oh, then of course whatever it took to screw on a hose barb up on the filter too right. I almost think I found them at the hardware store.

So anyway, there ya go. You can see about finding those and the cost. No doubt much more affordable, for two trucks even. Plus the other two fittings at filter head and some fuel hose to find total cost. Doesn't look pretty but matches the rest of the engine.
Doesn't stand out. I'll try and grab a photo of it on one the trucks tomorrow.

 

Thanks, I'll figure it out. I've seen Parker stuff being sold by Grainger, never heard of their own retail outlet though.
I'll do some more experiments but need a nice day or two as it's cold right now. I can cut trees or move dirt in this weather but rather don't play with the truck unless it's something urgent. Since I ditched my FSV she fires up pretty good in the morning after priming for a few minutes, so no rush.
Just came across this check valve and wonder if anybody used something like this: Aluminum Fuel Anti-Drainback Valve for Sale | Accurate Diesel

 

Not that you need these, but I was taking photos anyway, working on the engine in the F450. This is why my fuel filter base is laying up there. But as you can see, nice an neat and leak free. Just blends in.





^ There you can see, just a run of the mill 90 degree fitting, whatever the thread size is, to hose barb. Looking at it, I'm not so sure it's correct either. I have 3/8 fuel hose on there and I think that might be a 5/16 hose barb haha, well if so, neither truck is leaking. I think I better inspect this, if this is the case, I'll change those. Seeing this in photos makes me wonder. Could just be an illusion. I have more of this 3/8 fuel hose in the garage and I see it's kinda flat looking.

There's that jb-welded galvanized pipe plug, in the heater port, 10 or so years latter. Dry as a bone. Though I did use a brass plug on the F250, after plugging this one off.

 

This is what you need for the fuel line from Filter to Injection Pump.
Install hose onto IP, fill line with Fuel, ATF, or?? to eliminate air in the line.
then connect to Filter.
https://russrepair.com/filter-to-ip-...ne-delete-kit/

If you use Push lock Hose, do not use a clamp.

Like Tom mentioned, eliminate the line from Filter to #1 Injector. Did mine several years ago,
never had a problem doing away with it.
There was a TSB (Technical Service Bulletin) from Ford quite a few years ago to eliminate
it as it was causing a problem.

You could have air intrusion at the Lift Pump, or the curly Q hose going to it. Might be old and
cracked at the Clamps. Noticed my LP was wet on the bottom, and replaced it before it caused
problems.

Dont go buying another Injector return line kit thinking the new one is bad.
You can buy bags of 50 from McMaster-Car for around $10, size 111, Viton.
I reuse my old caps, and have a container of used caps. Got a bunch from PNP
off engines that had them recently replaced.


Charlie

 

Oh he's using the nice fittings out from his filter head too. That's nice. I should probably upgrade mine like those..........Yeah, I'm going to.