You must use the adapter to tap into the fuel bowl if you choose to read from either of those ports. then you use the NPT fitting. If you use an NPT fitting directly into the fuel bowl, you could damage the bowl as the NPT threads are tappered and the adapter seals with an o-ring.

 

I picked up a Motorcraft filter and gasket from the dealer this morning. The gasket is a different shape than the one that's on there now, still triangular, but different.

I inspected the bowl and the lid carefully for cracks or irregularities, didn't see anything. I CLEANED the lid and bowl interface surfaces very carefully, and then followed the installation instructions to the letter. Turned the key on, held my breath, NO LEAKS! In fact, even the other places I had thought I had seen leaks were not leaking. Maybe they never were, and what I was seeing was "ricochets" from the massive lid leak, or maybe they "were" leaking but "got better".

In any case, I but wasn't looking forward to slinking back to the forum and telling you guys "Yeah, it was the lid gasket", but hey, it was FIXED, and I could move on to the other things I needed to do.

Then I wanted to try one last thing, so I got out my stethoscope, turned on the key, and put the tip on the FPR outlet. I wanted to hear fuel going out through that thing while the pump was still running. All of a sudden, "PSSSSSSSSSSSS!!!" fuel is SPRAYING out of the passenger side of the lid, all over the side of the truck, all over the carport and everything inside of it. I ran for the key, and the neighbor kids learned some new words.

OK, so I was thinking back to the triangular gasket, and how the instructions said "turn the lid down until it makes contact with the gasket". No torque spec, no "full turn past snug" or anything like that. When I put it on, I went maybe a full turn past initial contact. Maybe I overdid it?

So, I backed the thing off, made sure the gasket was still in proper position and pointy side up, and then I turned it back down until it "just" made contact, then I only went a "little" past that, maybe a 1/4 turn.

Then, while hiding behind the hood and looking under it to see the fuel bowl lid, I cycled the key a few more times, and everything held. OK, maybe it's just that finicky for some reason, although I had never even had a hint of a problem in multiple filter/gasket changes in the past.

I finally got confident enough with it to put my stethoscope back on and listen for FPR flow again, but I was still kinda walking on eggshells. I could hear some flow, and then I turned the key off and put it back on there and I could hear what sounded like the poppet closing. Not totally sure about that.

I put the stethoscope down and cycled the key one more time, and I was leaning in to see if I could see any minor leaks in the back, and the lid seal let go on the passenger side this time and blasted me RIGHT IN THE FACE with a large stream of diesel. Fortunately I was wearing glasses, but my whole head got soaked, as did the OTHER side of my carport, and my vintage Land Cruiser. The neighbor kids learned even MORE new words!

I spent the next 45 minutes spraying everything with Simple Green and hosing down the carport, then I pulled one of the test plugs so I can hopefully find an adapter to let me do a pressure test.

So, what are the possibilities?

1.) FPR not working, and the fuel bowl just can't handle the full pump pressure? That's my guess at this point.

2.) FPR working, but for some reason return line can't keep up with flow from it? Don't think so though, because the bowl was leaking previously, with FPR in-place and return line disconnected, and nothing was coming out of FPR.

3.) Fill in the blank ________

I think checking the pressure is next on my list. The dealer does have the FPR guts, it's more than I'd pay online, but I could have them tomorrow.

I can't for the life of me understand why the FPR WOULDN'T be working, but that spring is awfully heavy.

Feel free to have a laugh at my expense. I'm laughing about it, now that I have all of the diesel washed out of my hair...

 

... Check the fuel pressure...

 

Heh heh... Next on my list Joe.

 

I know it sounds like I am repeating myself... well...

But it IS your issue. Something is wrong with your FPR or the return line.

You can use a cheap water pressure gauge from home depot... Just hook it up on the drain line.

 

I tend to agree. The ONLY reason I have not already done this is the difficulty of finding a fitting (locally). But:

Roger wilco.

Ya know, kinda getting ahead of myself here, but what started all of this was cracks in two of my injector sleeves. But the cracks were tiny, couldn't see light through them. I wonder if they were cracked for a while, but my fuel pressure jumped up and all of a sudden the problem got a lot worse? And maybe the only reason the lid didn't blow was because the engine was always running, so there was fuel demand. Anyway...

 

Looks like the male side of the adapter is 7/16-20 threads with the o-ring. The female side is 1/8 NPT, could be 1/4 NPT depending on your gauge...

 

Thanks, just found one on McMaster-Carr, 50925K172. I'll have it in the morning.

I have an old cylinder compression gauge that goes from 0 to 200 psi and has a 1/8 NPT fitting on it.

Of course to do this test I risk spraying diesel fuel all over my carport again. I guess I can just put a bucket or a jar over the bowl. My yard is starting to look like a hazmat site.

Part of me thinks the smart thing to do is just go get the FPR guts and put them in.

 

Remove the return line and blow some air thru it. Remove your fuel cap and you should hear bubbles. Not 100psi or anything, but 20-30 psi...

Just throw some shop towels over the lid, it will keep it contained in your valley.

 

Good plan. Worthwhile to make sure it's clear, and easy enough to do. Although, at one point, it was blowing diesel out of the fuel bowl lid while the FPR was in place but the return was disconnected, and nothing was coming out of the FPR. So I still lean towards malfunctioning FPR over a clogged return as the culprit.

Thinking about putting an FRx in. Seems like a good thing to have, and a good time to put it in. Since I am restarting the engine after having the injectors out, it might be helpful to keep air from getting to them. Thoughts?

 

Its not a bad thing... I need to get one on Chelsea's Excursion one of these days...

 

IMHO its just more places to have a leak and the benefits are, uh,,,,, well, mostly just more stuff to put in your signature...

Same goes for HPx...

There will be air from having the injectors out - just like when the engine was new. It will find its way out of the injectors and won't hurt a thing.

This is not a popular opinion, but the fact is nobody has ever made more power on a dyno or proven their injectors lasted longer etc from these mods. Let them tell ya why they think its a good idea though - I won't argue with them!

 

A full regulated return is obviously better, but the FRx is a neat idea that works as designed...

The HPx... well we agree on that one.

 

I learn so much here. FTE could be the best money I spend every year.

 

I agree, I like my FRx and the sounds it eliminates. I was on the urge of making and installing the HPx as well but decided against it because of no real benefit to it.

Cavitation is normally considered bad for any fluid system.