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Discussion Starter · #1 ·
I get air bubbles in the upper filter bowl when I cycle the key.
I've cycled it and emptied the bowl several times and continue to get bubbles.
It also seems to fill really slow and stops filling after about 20 seconds.
It takes 2 to 3 times of cycling it to fill the bowl to the top.

The truck was running poorly, no power, no boost. I changed both filters did the priming sequence thing it started, ran for a minute and now won't start.
 

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Discussion Starter · #3 ·
You didn't mention the year of the truck or model

Bubbles can come from a damaged suction line or a restriction in that line
when you changed the filter in the HFCM, did you lube the o-ring? and turn the cap until it bottomed on the threads?

The fuel bowl should fill within 3 to 4 seconds

it is also possible you have a clogged inlet line at the fuel tank, some of the metal tanks liner would flake off

It is normal for the pump to time out in about 20 seconds without the engine running -- when the engine runs, the pump is continuous
It's an '05 f-250 XL crew cab
Looks like it has a plastic fuel
tank but I didn't take a real close look at it.
I only lubed the o-ring with diesel as well as my arm and back
I did spin it on most of the way by hand

I wasn't sure what the pick up tube set up is. I'd assume I could take the bed off to get easy access to the top of the tank.
 

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Discussion Starter · #5 ·
Dropping the tank is pretty easy as long as it is near empty
you can loosen the passenger side bed bolts and remove the driver side
then tip and block the bed up a little, to get to the fuel pickup

Ford picked a really dumb spot to put that lower filter for sure
you need to grease the o-ring and be sure it is not "twisted" on the cap
the cap will bottom on the threads, unless someone has forced it in the past -- there is a stop on the threads

I have seen the pickup foot in the tank disintegrate and lodge pieces inside the line
so if that is the case, you would need to blow out the line with air pressure
I have over a 1/4 tank of fuel I don't have any means to empty it
I can use a cherry picker to lift the bed off.
 

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Discussion Starter · #11 ·
Thanks for all the info!
I'll tackle the tank first.
My gauge is showing over a 1/4 tank but I have no idea if it's accurate? I just haven't had the truck very long.
I may pull the hfcm out to look it over real good.
I did turn out the water drain plug, it seemed to be untouched. I drained it into a flat pan it didn't have any water.

I'm hoping the injectors aren't toasted but I won't worry about it until I can verify proper fuel pressure.
 

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Discussion Starter · #12 ·
ARRRGGGG!
Finally got the bed off and fought with the blue fuel line until I won.
Two of the bed bolts wouldn't come out, I didn't want to weld a nut to them, so I cut the top to match a 1 inch socket and they came right out.
The pickup unit looks brand new the screen was clean. There was a little bit of debris some was black some was a copper or brass color. I tried to get some of it out with a little oil vacuum but not much sucked up. I did run a magnet through what I did take out and some stuff stuck to the magnet. Not sure what that indicates but I'll assume it's bad.
I'd guess the brighter colored debris got there through the return line.
I'm thinking...take the hfcm off inspect it, blow out the pickup and return lines and put it back together.
I have the scanguage2 here are some of the data from it, this was all with the engine not starting.
FLP=12
FMP=48
CVI=5V
ICP=1400 or more while cranking
FMP=48v KOEO
IPR=53.51
SYC=1
Ideas anyone?
A little more info on the truck. It is a retired "slope truck" It likely spent a lot of time idling during the winters on the Arctic oil fields here in Alaska. I paid $3k for the thing. Other then that I don't have much history. I don't have any reason to bulletproof it, I'm looking for cost effective reliability for something that won't be worked hard.
Any ideas would be awesome.
 

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Discussion Starter · #13 ·
In the other forum, Eric had fuel delivery issues. There were a few problems, the blue spring kit had to be replaced, but the main issue was after 15 years, the foot in the tank disintegrated. That's been happening recently, probably due to age and the bio content in some fuels. As I mentioned, Ford does not supply these anymore, and on this and other forums the aftermarket replacements are not made from compatible plastic. The reliable alternative right now is to go to a sump.

A picture of what Eric found in his tank, and despite the cleaning and repair, still had issues probably due to debris in the feed line. A sump without the OE feed line has resolved the issue. He went as far as replacing the HFCM to no avail. A different issue due to bubbles, unless the foot is completely gone and the tank level is not where you think it is.

View attachment 769116
Inside of my tank was much better then that one. very little black stuff but it had some copper/brass colored stuff.
 

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Discussion Starter · #15 ·
Check the suction like from the tank to the hfcm for damage / pinched places
had a critter that bit my suction line and was not very obvious the damaged spot, only tiny puncture marks

You can substitute a 3/8 clear line in a jug for a suction setup to test if the bubbles go away

Some fuel bowls drain back(they are not supposed to) and when you do a filter out test, there may be bubbles
if you continued to run the pump the bubbles should clear up, would need a catch pan for the excess fuel tho
Making sure I understand.
Run a clear hose from the hfcm to a container to check for air?
I could do that with or with out the filter installed in the hfcm?
 

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Discussion Starter · #18 ·
You want to keep the filter in the hfcm, the line is just to eliminate the current suction line in case there is damage

you can add a second line on the return from the hfcm to the jug to eliminate the tank lines all together
the clear lines will let you see if the fuel runs clear or not - do this with the filters all in place
the 3/8 clear hose fits the connectors pretty well, but you still need a clamp
Ah Ha! now I got it!
I'm feeling less dense now
thanks. :)
 

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Discussion Starter · #19 ·
The weather finally got better 4 days of constant rain, didn't feel like getting soaked.

.
I pulled the filter off again made sure the cap was spotless, greased the O-ring and hand tightened the cap until the threads were out of sight. Also removed the water drain plug and greased it's O-ring a bit and put it back together.

I ran a clear line from the fuel tank to the hfcm it has no air when I cycle the fuel pump. The line coming out of hfcm is loaded with air. The fuel flow coming out of hfcm is really slow, not much above a trickle

Should I replace the fuel pump?
The lack of fuel volume just doesn't seem right.
 

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Discussion Starter · #23 ·
Ahh, then cap both return ports on the HFCM, likely pulling air from the return, either thru the tank or the filter housing

The low flow is concerning, just had mine off a while back to check how low it would go before I was out of fuel (138 miles ...lol)
anyways the fuel flowed out of the line about 2-3 inches with the line horizontal
this all depends on if you have a restriction in the tank or in your line adapter
you could place the end of the clear line an a clean container to see if the pump flow increases

The pickup foot is gone in my tank, that is why it runs out of fuel at 138 mile -- the after market foot is not of quality so I am told
so looking into a sump kit, or possibly making a sump -- I have the tools
just can't see boring a 3 inch hole in my tank, ...lol
I had pulled the pickup unit out earlier, it looked new.
Looks like I have a few more things to chase down.
I may measure the amount of fuel that comes out. It doesn't push with much force, more like falls out of the end of the hose.
 

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Discussion Starter · #24 ·
I checked the amount of fuel it pumps when cycling the key on. I cycled it twice it pumped out just under 8 ounces of fuel.
I also rechecked to make sure I had the right torque on the cap.
I'm not sure if I need to mess with the air bubbles too much more at this point. If it looks like I need a new pump, I'll end up going through the hfcm anyway.
Ideas?
 

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Discussion Starter · #29 ·
Here’s my favorite fuel trouble shooting video. I think it says also that the low pressure can be caused Be a clogged line from the tank to the pump and this explains how to check that.


When I first read the title, I thought this was a fuel injector related thing from the upper fuel bowl failing a bubble test.
I had the same flow out of the hfcm after bypassing the factory lines from the tank pickup to the hfcm.
I doubt that line is plugged or restricted.
I'll probably do some fuel pressure checking after I get past the hfcm problem.
Thanks!
 

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Discussion Starter · #30 ·
Well poop!
I went to a junk yard picked up a used hfcm. Spent awhile cleaning it. I mounted it back on the truck ran my clear hose from the tank to the hfcm and a clear hose on the engine side of the hfcm to a fuel can. I had both the smaller lines from the hfcm plugged off. After cycling the pump on a few times I got clear fuel (no air bubbles) coming out of the hfcm.

The used hfcm pumped a lot more fuel then my original one, so I'd guess the original had a bad fuel pump.

I removed the clear line from the tank to the hfcm and attached the factory line and plugged in the two smaller lines with the factory connections I left the clear line from the hfcm on the engine side draining into a fuel can.
When I cycled the key on I pretty much got fuel that looked like foam coming out of the hfcm.
I replaced the factory line from the tank to the hfcm with black rubber fuel line, still had the same foam coming out.
I plugged off the two return lines one at a time and tested. The air seems to be coming from the engine side return line.

I guess the hfcm has a check valve that isn't working right?

Would it be a dumb idea to reconnect everything and see if it clears up with all the plumbing connected?

I was trying to avoid buying a new hfcm if all I now have is a fuel line sucking air.
 

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Discussion Starter · #35 ·
What’d you do to fix it?
I pretty much covered it in post #30.
I didn't want to spend a ton of money and find out my pump was good. I had a good idea it was bad.
I picked up a used hfcm for $80 from a junk yard, I wasn't taking too much risk with the used one, they would take it back if it didn't work. I cleaned it to death and put it back together. It works just fine although I'd still like to run a pressure check up top and do the blue spring kit.
I did bypass the stock line from the tank to the hfcm, I didn't like the way it's connection to the hfcm felt, it seemed sloppy.
On the plus side the used hfcm I picked up had a brass water drain plug.

I should clean up the old one and see if it just isn't plugged up internally.
 

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Discussion Starter · #37 ·
You still don't know what risk you have incurred until you check fuel pressure............. And even then, the failure rate of a junkyard pump has to be higher than that of a new pump - making a fuel pressure gauge even more important. The 6.0L will run fine on fuel pressure that is pretty low - right up until an injector fails.
You are right.
I will be checking it. I just have to get the stuff together to do it.
I'm running out of summer quickly.
 

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Discussion Starter · #39 ·
Yknow, the fuel pump by itself isn't that expensive, nor is the service kit for the hfcm. Why not just "rebuild" the one you took off?
It was a time and weather issue.
In a couple weeks we'll start getting frost at night and I was working between heavy rain storms. The truck sat for for days with the bed on the ground next to it because of the constant heavy rain. working on the top side in a little rain isn't a big deal but laying under the thing in the rain is out.
I will probably rebuild the original hfcm and keep it on hand. If I see a pressure issue with the used one I'll be go to go.
Mail delivery as be a bit messed up lately, some stuff arrives at normal times some stuff takes forever. I didn't want to order something and have to put it on in the snow. I'm not a total wimp I've changed a starter more then once in below zero temps.

I didn't know there is a service kit for the hfcm. I'll look into that.
 
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