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Check valve in fuel line

9K views 16 replies 7 participants last post by  Extended Power 
#1 ·
Since I have done the regulated fuel system on my truck, I can see that when the truck is "Buzzing" the injectors, the fuel pressure climbs from 0 Psi to 52-54 Psi.
This tells me that the fuel system is leaking down.
The banjo bolts in the back of the heads are modified...cross drilled and opened up quite a bit. the regulator "should" hold the system at the set pressure...which leaves the stock fuel pump to be the culprit. (It's not the injectors...I have had my oil analyzed at every change, and have had NO fuel dillution at all.)
Do you think it would be a good idea to put a check valve into the main fuel line just before the secondary filter?

-Good- the system would be fully pressurized for every start...eliminating the chance of running the injectors dry, or, with low fuel pressure.

-Bad- the sytem would keep the fuel system fully pressurized and if any injector was bad...it would leak into that cylinder...


What are your thoughts on the matter???:shrug: :popcorn:
 
#2 ·
EP,
are you talking about the wait to start period as the buzzing the injectors or the actual cranking event?..mine jumps upto 55psi from zero when I key it on as fast as the little needle can get there....well before I crank it ....if your is not comming up tell you actually start cranking the engine then something is up....
Jschall
 
#3 ·
No, no...the pressure comes up right away when you turn the key on...BEFORE you crank it over.
I am wondering why the pressure drops to zero when you shut the truck off. It does not drop right away...it takes a little while.
I am wondering if there is a benefit to having the fuel system "Locked-in" at 52 Psi when the truck is shut off.
By putting a check valve in place right before the secondary filter...the fuel pump could still back off, but the rest of the system would/should remain at 52 Psi. Then again...maybe not...:shrug:
Just wondering if there would be any benefit to having it in there...or maybe even just after the pump...I don't know.:squish
 
#4 ·
Sorry Jeff...looked over my first post again, and it looks like I said that the system is leaking down when the key is turned on....:damnit

I was trying to say that...BEFORE I turn the key to the "on" position, the pressure is at zero Psi everytime. This tells me that something is leaking down when I last turned the truck "off". And I believe it to be the stock pump.
 
#6 ·
the fuel will leak back past the pump when you shut the truck off, thats why the pump runs when you first turn the key on, pump runs and fills the system again before start up. when you do the fuel system mod, just remember to let the pump run for a few seconds before firing the truck
 
#7 ·
I think EP the buzzing is an electrical event not envolving the need for hydraulic lubrication so I don't think it would matter...but it's gonna take Tadd or Bean (Injector guru) to let us know for sure...
jschall
 
#8 ·
UNBROKEN said:
I've run well over 50,000 miles without those check valves...both with the first drilled banjo mod and now with a full, stand alone fuel system.
I wouldn't worry about it if I was you.
Those are not the check valves I am talking about. I am talking about an aftermarket check valve installed right after the fuel pump itself.

I have had the front banjo-bolts modded since "Choke" was the "Mr. know it all/done it all"

I had new bolts to put in, if needed, for the new fuel system. But I used the modded ones from the front, and put them on the back of the heads. No sense in restricting the flow to the regulator. (That's "it's" job)
Then I used drilled out 5/16" fittings on the front of the heads.
I guess the system will have fuel all the time, just not the pressure. And it don't take long to build pressure with a liquid.:Thumbup:

No worries.........:Thumbup:
 
#9 ·
The factory banjo-bolts used in the fuel pipes are REQUIRED to dampen fuel pulsations in the fuel system during normal operation.

Removal or modification of these valves can, and will, ultimately cause injector damage or even starved injectors.

Installing a one-way-check in the SUPPLY of your modified fuel system WILL reduce the leak-down you experience with the key off. It will also INCREASE the restriction in the fuel supply system, which is TOTALLY counter-productive. It is, however, your only choice at this point.
 
#10 ·
Removal or modification of these valves can, and will, ultimately cause injector damage or even starved injectors.:shrug:

What do you think the stock system is doing??LOL :poke:

This is half of the reason for replacing the stock fuel system, as it does not have enough volume for the trucks to run flat out.
With the new fuel system in place, the 5/16" braided lines that feed the front of the heads...along with the 1/4" braided lines coming off the back of the heads...going to the regulator, (Which has a SS, liquid filled 2 1/2" gauge in it) does a WAY BETTER job of dampening the pulsations in the system than the little spring loaded check valves in the HARD lines of the old system.
The gauge itself does not show any pulsation movement at all, and I can bearly feel any pulsation in the braided flex lines.

Maybe we could ask Tadd about ATS's system, as mine is pretty close to their STAGE 2 fuel system. I don't think that ATS would sell something that would knock out a set of injectors. I think Ford just took the easy way out, and just put in half of the fuel system to save money. Don't know...just thinking out loud...

And I am in no way trying to "Slam" ATS's product's...:mafia



EP
 
#11 ·
John_G said:
The factory banjo-bolts used in the fuel pipes are REQUIRED to dampen fuel pulsations in the fuel system during normal operation.

Removal or modification of these valves can, and will, ultimately cause injector damage or even starved injectors.
.
I know you're a knowledgable guy with these motors...but what you just posted is incorrect....maybe not in their function...but in what will happen if you remove them. I'm sure that's Ford's or INternational's stance...but trust me...the injectors are just fine without them.
 
#12 ·
Extended Power said:
Removal or modification of these valves can, and will, ultimately cause injector damage or even starved injectors.:shrug:

What do you think the stock system is doing??LOL :poke:

This is half of the reason for replacing the stock fuel system, as it does not have enough volume for the trucks to run flat out.
With the new fuel system in place, the 5/16" braided lines that feed the front of the heads...along with the 1/4" braided lines coming off the back of the heads...going to the regulator, (Which has a SS, liquid filled 2 1/2" gauge in it) does a WAY BETTER job of dampening the pulsations in the system than the little spring loaded check valves in the HARD lines of the old system.
The gauge itself does not show any pulsation movement at all, and I can bearly feel any pulsation in the braided flex lines.

Maybe we could ask Tadd about ATS's system, as mine is pretty close to their STAGE 2 fuel system. I don't think that ATS would sell something that would knock out a set of injectors. I think Ford just took the easy way out, and just put in half of the fuel system to save money. Don't know...just thinking out loud...

And I am in no way trying to "Slam" ATS's product's...:mafia



EP
ep your fuel system sounds fine to me. the lines running from the back of the heads to the regulater are what help keep the pulsation and pressure spikes down,thats what the fuel crossover line is for. people whithout a full return fuel system can put a crossover line on to help this.
 
#13 ·
I have no interest in arguing with anyone, about this or anything else.

I ask you to think about one thing...

Do you REALLY believe that International engineers would use a "special" banjo-bolt in lieu of a standard one, if there were not a VERY GOOD REASON for it? They are about 50 times more expensive, than the standard ones, FYI.
 
#15 ·
I've ran mine both ways off and on at different times. I could not notice a difference really, once I thought it felt stronger at WOT. Has anyone backed this up on a dyno? I'm just curious, by looking at them, they don't really look restrictive. And I've not noticed any downside to removing the check valve either. I do agree that it is there for a reason, but what reason. My truck does not seem to run out of fuel WOT like a few others I've driven without this mod and the same tuner.
 
#16 ·
I think John G is right for the stock system.....the stock system with the stock pump and stock lines and stock programing needs those checks to do what he says....now once you make a full return system with bigger lines and bigger pump or cross over you have other parts performing their function or compensating in another way......with stock programing you don't run out of fuel wot ...but with a tune you do...so what's worse running out of fuel or pulse vibrations that is the choice you make if you stay with the stock system and a hot tune....running out of fuel is worse Imop...
jschall
 
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