fuel filter check valve

[pat_da_man]

Hi guys
New to this site
I am thinking about putting in a check valve just prior to my lift pump in my 92 7.3L f250. I'm wanting to do this because my fuel filter is draining, causing my truck to start and run for about 10-15 secs then stall and take about 30 secs of cranking to get it started again. After this it its good to go. If i fill my fuel filter with fuel it is good to go. It seems there is suction causing this, as if i unsrew the fuel filter and let it suck all it wants, then fill the filter with fuel it starts fine, even if it sits for a few days. Anyone see any problems with putting in a check valve or backflow preventer in? or anyone know any other solution?
Thanks

 

[suv7734]

The probable cause of your problem is leaking injector retun line caps/o-rings. You may or may not see fuel leaking around the top of the injector(s) but they can allow air to leak into the system which allows the fuel to leak back overnight. The kit is about $40.00 depending where you get it and it includes all the caps, o-rings, line, clamps and copper washers for installing the injectors (which aren't needed to do this job). Where are you in Vancouver?

 

[pat_da_man]

i agree with you however i just replaced them all thinking the same thing. the thing that gets me is really how fast the filter seems to drain yet i dont see any fuel leaks. I'm gonna stick in a new fuel filter next to see if maybe theres a bad seal. is the suctions i'm seeing normal? i can hear it when i take off my fuel filter after i've gone for a ride.
i'm from the north shore
thanks for the reply

 

[MIDNIGHT RIDER]

The check-valve is a good idea and not a bad idea even on a healthy system.

McMaster-Carr is a real good internet source for such things of good quality at a fair price.


Another upgrade is to add the check-valve ahead of the lift-pump, also TEE another "bypass" line ahead of the lift-pump and ahead of that check-valve, such that this line makes a loop that bypasses the lift-pump, tee-ing back into the fuel-line after the lift-pump; in this bypass line, an electric pump is plumbed in, with another check-valve at the outlet end of the electric pump.


How this helps is, you leave the electric pump OFF, and the mechanical lift-pump functions as it always did.

The first check-valve prevents fuel from draining back to the tank.

The other check-valve prevents fuel back-feeding through the electric pump and bypass line.

Then, when the fuel system needs priming, the electric pump can be activated, thus filling the filter and charging the lines with fuel.


Another PLUS = the fuel-filter can be filled by the electric pump when changing filters.


Another PLUS = should the mechanical lift-pump fail, the electric pump can be activated and the big wheels keep a rolling.


A TEE can be added down-stream of the electric pump, with a ball-valve cut-off on the leg of the TEE, then a long fuel-line extending to a CAPPED end.

The cap is to keep out dirt and keep in fuel.

The cap can be removed, and this line and the electric pump be used to pump diesel out of the truck tank(s) into another container or tank.

ALSO, should a tank require repair, the fuel can be pumped out of that tank by using the electric pump.

 

[RLDSL]

Might want to take a look at the rubber seals in the ends of the metal fuel lines at the filter and the injection pump. If they're old, they may be pretty crumbly.

 

[Agnem]

The check-valve is a good idea and not a bad idea even on a healthy system.

McMaster-Carr is a real good internet source for such things of good quality at a fair price.


Another upgrade is to add the check-valve ahead of the lift-pump, also TEE another "bypass" line ahead of the lift-pump and ahead of that check-valve, such that this line makes a loop that bypasses the lift-pump, tee-ing back into the fuel-line after the lift-pump; in this bypass line, an electric pump is plumbed in, with another check-valve at the outlet end of the electric pump.


How this helps is, you leave the electric pump OFF, and the mechanical lift-pump functions as it always did.

The first check-valve prevents fuel from draining back to the tank.

The other check-valve prevents fuel back-feeding through the electric pump and bypass line.

Then, when the fuel system needs priming, the electric pump can be activated, thus filling the filter and charging the lines with fuel.


Another PLUS = the fuel-filter can be filled by the electric pump when changing filters.


Another PLUS = should the mechanical lift-pump fail, the electric pump can be activated and the big wheels keep a rolling.


A TEE can be added down-stream of the electric pump, with a ball-valve cut-off on the leg of the TEE, then a long fuel-line extending to a CAPPED end.

The cap is to keep out dirt and keep in fuel.

The cap can be removed, and this line and the electric pump be used to pump diesel out of the truck tank(s) into another container or tank.

ALSO, should a tank require repair, the fuel can be pumped out of that tank by using the electric pump.

Ouch! Fancy engineering, but probably waaayyy overkill. How about we just fix the problem and not the symptom, hmmm? Lots of folks have struggled with air leaks, but throwing parts and money at it is not the best way. A few pieces of cheap clear vinyl tubing work wonders at locating the source. If you feel you must replace something, just scrap the mechanical lift pump and go electric. That has benefits all the way around.

 

[icanfixall]

The mechanical lift pump already has a check valve in it. This may be the lose of prime problem too. Most here like the electric lift pump idea. I know I sure do.

 

[pat_da_man]

electric fuel pump

do you guys suggest a particular fuel pump?
i think i've seen people use red holley? or something like that
think i might put both electric pump and a check valve in
thanks for all the info

 

[Agnem]

The Holley Red is the gold standard. There are other brands in use that work OK too, but the Holley is the nicest and is serviceable.

 

[MIDNIGHT RIDER]

I actually prefer a mechanical lift-pump; it will pump so long as the engine is running.

But, I also like my idea of a "back-up plan" electric pump that can be switched on demand; should the mechanical pump fail.


I have seen more than one of these trucks that had so many miles on the engine that the cam no longer had enough lobe to properly operate the pump.


Another source for an air leak is the hard-line from the filter to the injector-pump.

I replaced those O-ring seals 'til I was blue in the face and still had a leak.

I finally discovered a hair-line crack in that hard-line.


Replaced the line and no more leak.

 

[pat_da_man]

hehe stupid me

well there i was looking around to see if i could figure out the problem when i was like whats this doodad and what do you know there was already a check valve installed. i opened it up and found some pine needles keeping it from shutting so i cleaned it out and so far so good i guess its a good thing my truck has two fuel filters, but anywho now i am going to keep my eye out for a sweet deal on one of those fuel pumps while i try to fix the massive exhaust leak i found