Abundant Fuel Pressure

[amsterdam96]

Happy new year to you all!
I've concluded that my engine is getting 'flooded' with gasoline. There used to an MSD ignition system installed that created a more powerful spark. This has been disconnected, I'd like to keep it this way in order to pass inspection.
However the old modified fuel line is still in place & unchanged. Seeing as I don't have a clue what a stock GM fuel line looks like I'm unsure as to what I can disconnect.
Between the tank and the fuel-rail there is pump no.1 (or two if the one in the tank is still in place) a pressure tank, pump no.2 and then the fuel filter.
There's abundant fuel pressure. I will test it when I have working test-kit. I'd like to get to work beforehand though.
Can I drain the tank without damaging the stock fuel pump that's in the tank? Has anyone ever seen a high-pressure fuel system like this one? Isn't the pressure tank useless?
Thank you all for reading.

 

[east302]

The stock pump is supposed to deliver 60-66 psi at the test port on the driver side intake (assuming this is a 96 350). The pumps in series are additive - the flow is the same but the pressure is added. So if you have a stock pump putting out a little over 60-psi and then have a second inline pump then you have 60-psi plus the pressure developed by the second one.

In theory, the regulator should be relieving any excess pressure back to the tank, but there may be a limit to how much pressure it can see upstream before it cannot handle it and the line pressure goes up. The fuel lines themselves are probably rated for a fairly high pressure, but the injectors may not be.

If the cylinders are flooded, then the injectors are probably leaking. It may be that they are damaged and/or cannot close against the higher pressure.

What is your pressure at the test port with ignition on/engine off?

The stock pump can be removed by dropping the tank without damaging it. That’s how they are replaced - the tank being as empty as possible to save on weight when lowering it.

Not sure why you’d have two pumps, maybe someone else can take a shot at that.

 

[Erik the Awful]

The fuel pressures are not necessarily additive, it depends on whether or not the second fuel pump is internally regulated. It if is, it's regulator will limit the output pressure.

The separate tank is a surge tank. It's extra insurance when you have a tank that tends to pick up air when it's below half, or when you're running nitrous. It's also common on modern diesels when you don't want to run 30' of high-pressure line. The way this is normally set up is the first pump is a high-volume, low pressure lift pump and the second is the pressure pump.

All this is moot until you check your fuel pressure. Keep the gauge hooked up, and after an hour read the gauge again to see if your injectors have leaked.