AGP Twin Pump Fuel - Does it have a check valve?

[cc-rider]

Does anyone know if the AGP twin pumps have a one way check valve built into them? Or do I need to add one in-line…

[jeff657756]

You dont need to add one.

[cc-rider]

I do need one with the way I want to wire it up. I'm using the green FPCM wire to trigger the relays. This way I can keep my priming function enabled. And then the pumps won't run constantly when key is on. Green wire also keeps the safety functionality of the FPCM working as well and will shut the power the pumps off in the case of an accident. But...without a check valve, the fuel pressure will not hold...and the priming function doesn't go off every single time the key is cycled. So a check valve is needed to run it this way.

So, back to my original question...still wondering they have a check valve somehow built into them. Tried to call AGP but nobody there called me back. Perhaps will try again there.

[larry_g]

Not AGP but I don't have check valves and even when it doesn't prime, it doesn't really take any more cranking to get it to start.

I thought the same thing when building my system, but with a return style and fuel pressure regulator, it's still going to flow back to the tank anyway.


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[cc-rider]

Originally Posted by larry_g

Not AGP but I don't have check valves and even when it doesn't prime, it doesn't really take any more cranking to get it to start.

I thought the same thing when building my system, but with a return style and fuel pressure regulator, it's still going to flow back to the tank anyway.


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Interesting. So are you triggering your pumps off the green/white FPCM wire as well? That wire is on for the priming time...but then also on during cranking and run as well. I'm already hooked to that green/white and would just prefer to leave it as opposed to switching to the pink wire that is constant 12v key/crank/run.

I did finally get in touch with AGP. He confirmed that the AGP pumps do not have a check valve. Claimed to have played with them many times in an effort to try and get it to work right. But it would always bleed pressure. From both the supply and return. I guess I had thought that the regulator would hold the pressure with a check valve in place on the supply line. But apparently they must not close off completely below their pressure set point.

[larry_g]

Originally Posted by cc-rider

Interesting. So are you triggering your pumps off the green/white FPCM wire as well? That wire is on for the priming time...but then also on during cranking and run as well. I'm already hooked to that green/white and would just prefer to leave it as opposed to switching to the pink wire that is constant 12v key/crank/run.



I did finally get in touch with AGP. He confirmed that the AGP pumps do not have a check valve. Claimed to have played with them many times in an effort to try and get it to work right. But it would always bleed pressure. From both the supply and return. I guess I had thought that the regulator would hold the pressure with a check valve in place on the supply line. But apparently they must not close off completely below their pressure set point.

Yes, I am using the FPCM wire. I have it setup so it triggers the relay on my first pump. If I've shut the car off recently it won't prime again but the pressure builds quickly as soon as I start cranking.

My second and third pumps are triggered by Hobbs switches.


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[cc-rider]

Got it. Thanks for that info. I guess I’ll just give it a shot without the check valve.

[jeff657756]

Originally Posted by cc-rider

Got it. Thanks for that info. I guess I’ll just give it a shot without the check valve.

People do have been doing it both ways for years. Constant ignition source or off the green fpcm wire. Both ways work. I use the ignition source and just turn the key on for a few seconds. You can hear it prime. After a few seconds crank it up.

[4SFED6.0]

I run a check valve in all of my return style set ups for more consistent starts, the easiest way to do it is to run an inline filter with an integrated check valve. Not sure if your wiring is done but its advised to get your signal from the wire going into the FPCM, DO NOT run direct ignition power to your pump relay, if there was ever an accident your pump would keep running if the key was on, the wire from the fpcm would shut down after the ecm doesn't detect an rpm signal.

[cc-rider]

Originally Posted by 4SFED6.0

I run a check valve in all of my return style set ups for more consistent starts, the easiest way to do it is to run an inline filter with an integrated check valve. Not sure if your wiring is done but its advised to get your signal from the wire going into the FPCM, DO NOT run direct ignition power to your pump relay, if there was ever an accident your pump would keep running if the key was on, the wire from the fpcm would shut down after the ecm doesn't detect an rpm signal.

I’ve got it wired to the green/white wire running into the FPCM. So I should be good to go. I am going to run a check valve too. Can’t hurt I guess. the regulator must hold some pressure for a bit of time. If not, at least the fuel line will stay full all the way up to the rails/regulator. Should help it pressurize quicker.