GT40 fuel delivery problem

Thanks Mark

What would be a good way to test out of the boat Mark.? I know some who rebuild English electric diaphragm pumps use mineral spirits for the fluid.

Better for you to spend 3 days than taking it in and paying someone else! Glad it worked out.

If you have 12V at the pump with ignition on you can forget about wiring and relays.

What was the source of the second HP pump you tried, new ??? (I think you have two bad HP pumps)

The wire you re connected may have been the retrofit that PCM did to eliminate the troublesome large fuse in battery box for ECU power. Have a look at this old thread ECC Power Retrofit

Paul (Gun-driver) did a lot of work on the non FCC GT40 HP fuel pumps not sure if he found a replacement or went with the FCC conversion Gary posted. Will see if I can find Paul's thread.

Edit:
Found the replacement thread but the one with all the troubleshooting was more elusive Non FCC HP replacement pump

Lewy2001 is the FI expert here,when he see's this I'm sure he'll respond. Randomly connecting wires without testing could lead to trouble. Might be that it was already disconnected and bypassed, as per PCM's instructions. Thats why you need to test voltage to pumps and fuel pressure before you start disconnecting and connecting wires.

LP pump is brand new, I unhooked the HP from the LP hit the key and get fuel. Fuel filter is new, even the line from the tank is new. Engine is a zero hour rebuild. I saw the fuse wire that connects directly to the battery had been cut, so reattached it. May try a new fuse, but I don't really know what that fuse controls. Calls itself a fuse-time delay for fusing the fuel pump. I may go find a new fuse, but still get power to the pump. Anyone know the function of this fuse?
The truth is GaryS, it's possible that both HP pumps I have are bad but when you hook up power to them, they kick on. Even if they aren't pumping the fuel at a high enough pressure, I should at least see fuel come out of the other end..I would think

You might try replacing both of the relays located by the ECM but since you have power I suspect that's not the problem. Check your fuel filter. My Hp pump was squealing real bad and starving for fuel due to a clogged filter. If that doesn't fix it, it may be your pump. Unfortunately those high pressure pumps are NLA. The issue is finding a 2-port hp pump on the intake side for the return line. carter p5000 or p61171 is a 1-in 1-out pump available on summit but you would have to re route the fuel return to the inlet side with some new fittings (y) or cap it. There has been some discussion on team talk about this since indmar used the same HP pump for quite a while Here

Not sure if any Nautique owners have tried this conversion since I believe Nautique only used the pump in 95 then went to the FCC. I suppose you could also convert the whole system to FCC but that would take a little more $.

Kyle

Which system do you have, with or with out a fcc? Have you verified what the fuel pressure is at the fuel rail?