Problems Again.
I'm still dying after running for a while.
I installed a glass filter just before the pump to see what is happening.
The fuel filter is full of bubbles when it starts lossing power.
I filled the tank to 3/4 to ensure that the in-tank mod was not the problem.
Still sucking air from somewhere.
Has anyone had problems with the lines. between the tank and pump.
I did replace the o-ring connections on top of the tank, and pump input.
Was very careful to make sure all hoses were tight.
Any ideas where this air is coming from?
temps in high 20's and lower 30's .
I need a plan of attack.

 

Now that you mention that I believe there was a post a while back about air sucking in on the suction side of the fuel pump I wanna say kwikordead posted about that if I remember right it might even have something to do with the famous fuel cackle.

 

Yes there is a history of pulling air on the suction side of the fuel system.
Do a search for the "pre pump mod". Should answer your questions.

 

IF the pre-pump is the same as the in-tank mod, It's already done.
I did the intank and replaced the fast connect on the pump.
I added extra fuel just in case the leak was still in the tank.
Maybe i have a leak around the filter somehow.
Anyone have problems with the metal line between the pump and the
tank?
I was having the same problem before i started all the mods.
New cps, new fuel filter, in-tank/pre pump mod , 3/4 full tank.
If i blow thru the pump with compressed air it seem to run much longer before i have problems. I just added the glass inline filter and now i can see the air in the filter.
I thought the pump was going bad but when i see air in the pre filter i don't know.
Any suggestions?

 

Those connectors suck air big time!
You've done the hard part, now get rid of all the quick connects between the tank and the inlet side of the fuel pump and replace them with high quality fuel injection rated flex line with double clamps at every union. That will cure your air problem.
Here's my story:
https://www.ford-trucks.com/forums/s...d.php?t=260173

 

I "THINK" I finally got it fixed for good.
Found a couple problems.
1. trash in my tank. (don't know how you get trash in a plastic tank)
2. cheap hose clamps that would not allow full tighten.
3. fuel filter on backwards.
4. leak at water separter purge hose.

This is what i think was happening.
The intank filter clogged.
When i did the intank mod which removed that filter the trash clogged the pump with no filter.
That explains why it ran good when i blew thru it.
Then i put a glass filter on. (backwards)
When the filter started to clog it would put a valcum on the inside of the glass filter
housing to pull the fuel thru the filter media since it was clogged it sucked air thru the oring in the filter and hose clamps . ( i could see the bubble)
When i cleaned the filter and PROPERLY reinstalled the filter with better clamps
i can see the trash accumlating in the filter but no air at all.
I put a guage on the water separter hose to check fuel pressure.
60 psi at idle but drops with key off. when i closed the valve the
and restarted the engine the guage still works .
Great malfunction for me I'll just leave the guage installed instead of fixing it.
I will have to unscrew the guage before i drain water but that is a small price to
for a $13 guage.
Harbor Freight sell a fuel injector pressure guage kit for $13.
It has guage and several different adapters, one of which is a barb.
Just add 2 feet of fuel line, one end on the water purge and the other on the barb adapter. Screw in the guage and open the valve.
Instant fuel pressure guage.

Almost forgot,
IT RUNS SO SMOOTH AND QUIET YOU WOULD THINK IT'S A GASSER!
Better throttle response too.
THANKS TO EVERYONE .

 

Update.
I was right, trash causing all my problems.
When my engine started getting noisy again
i check fuel pressure guage ,it was around 45 psi normally 60.
I check the glass filter and it full of trash.
This is the third time i've cleaned this filter, but it has a very small filter element.
Runs smooth and quite again.
How does one get this much trash a once.
I'll had the truck for almost 15k miles and not a problem.
I had been using diesel kleen, but tried the mystery oil not too long ago.
Do you think i cleaned something, or just get a bad batch of diesel ?
This can't be normal for the fuel system to clog like this, can it?

 

I think through the recent "fuel shortage" there was some really trashy diesel sold. I used to change my fuel filter 3 times a year, have been changing it monthly lately.