Issues with a 1 way fuel check valve not working

[cruizin01]

I recently reworked my fuel system to move the fuel pump into the tank. I ended up with a fuel pump that didn't include a check valve. No big deal I thought, Ill just add a check valve.

I bought and installed a basic spring-loaded valve from Jegs and installed it after the regulator and before the holley sniper. So when I key on, the pump runs and primes. When it shuts off the fuel pressure instantly declines until it gets to zero in about 20 seconds. (the gauge is on feed at the sniper)

I took the check valve apart and it functions correctly. So I can't figure out whats going on. Can anyone think of anyway the fuel would bleed off with a check valve functioning? I assume if the injectors were leaky the engine would flood and I would smell it.



This is the valve.
https://www.jegs.com/i/JEGS/555/1500...RoC1P4QAvD_BwE

[homemade87]

Is the valve designed to hold pressure or hold the volume of fuel in the line from draining back . The description says , Internal leakage less than 1 D.P.M. (drip per minute) . This does not sound like a pressure device . It sounds like it will keep the fuel in the lines which is what you want to do . The instant the key is on the pressure will be what it needs to be . This does not seem to be a problem to me . No need to hold fuel pressure when key off . I do agree if it falls in 1 second then I would be a little more concerned .

Call jegs and see if they have a little more info to how it is supposed to work and let us know what they say .

[cruizin01]

Originally Posted by homemade87

Is the valve designed to hold pressure or hold the volume of fuel in the line from draining back . The description says , Internal leakage less than 1 D.P.M. (drip per minute) . This does not sound like a pressure device . It sounds like it will keep the fuel in the lines which is what you want to do . The instant the key is on the pressure will be what it needs to be . This does not seem to be a problem to me . No need to hold fuel pressure when key off . I do agree if it falls in 1 second then I would be a little more concerned .

Call jegs and see if they have a little more info to how it is supposed to work and let us know what they say .

Whether its pressure or volume it doesn't really matter imo. It doesn't hold either.

If I key on but don't start the truck right away the pressure dies off and the truck long cranks until the pump is able to build 58psi of pressure in the line again.

Called Jegs and the only thing they could recommend was placing the valve before the regulator. Not sure why that would matter. Its going to see ~80psi instead of 60psi. Not sure how that's gonna effect anything but maybe Ill do it before I swap it out for another one.

[Bigdav160]

Even fuel pumps with built-in check valves do hold pressure for long. The pressure bleeds off and the line remains full of fuel. When the pump starts it almost instantly returns the line to full pressure.

Sounds like you are losing more than the pressure though

[Coley]

Some of this may be tied to the fact that fluids aren't compressible.
So if there are fluids on both sides of the check valve when things shut off...and the check valve was open (and flowing fuel) at the time...then the check valve won't collapse unless the fluid (fuel) on that side of the check valve has a place to go.
All the springs in the world won't move that fluid if it is 'locked' into a tube or pipe....literally no spring in the world, given the physical fact that again, fluids are not compressible.

All good
Coley

[SunSoaked]

Why are you thinking you need a check valve in the first place? I ran a Sniper without one and it worked fine. It primes every time you turn the key on. On the other hand, the Sniper turned out to be the biggest POS I've ever dealt with. Tossed it and went back to Edelbrock carb. Couldn't be happier. I hope you have better luck!

[cruizin01]

Originally Posted by SunSoaked

Why are you thinking you need a check valve in the first place? I ran a Sniper without one and it worked fine. It primes every time you turn the key on. On the other hand, the Sniper turned out to be the biggest POS I've ever dealt with. Tossed it and went back to Edelbrock carb. Couldn't be happier. I hope you have better luck!

The truck long cranks if you don't immediately start the truck when you key on. I want to fix this.

My sniper works and runs fine. Ive put 500-1000 miles on it without any issues.

[cruizin01]

Update.

After going back and forth, not quite knowing what direction to take I decided to try replacing the "new" fuel pressure regulator. It wasn't an ebay one but it wasn't an Aeromotive either. So I ran to jegs and got an Aeromotive unit to try out.

Its 90% fixed!

It takes several minutes to bleed off to zero. It does bleed to 40 pretty quickly but then very slowly after that. The pump seems to be able to bounce back a lot quicker as well as soon as I put power to it. Its still weird by the check valve wouldn't hold the pressure in the line even with a junky regulator.

I have the worst luck with junky parts right out of the box. Even when I try to buy OEM parts a lot of times I get dead ones.

Either way Im satisfied with it for now.