E-Fuel - Is priming necessary?

[PsRumors]

When I installed the AirDog it was wired as key on / pump on. I am currently installing an oil pressure switch to trigger the relay so that the pump only runs when key on / engine run exists.

My next step, I was thinking about triggering the relay with a feed from the glow plug system (through a diode). This would allow the fuel pump to build pressure prior to starting but if I needed to work on the truck the pump wouldn't always run with the key on.

Is this necessary?

Doesn't the ECM control the ground of the glow plug relay?

 

[mjonesjr]

You won't need to prime the system. If you have the oil pressure switch, once the cranking process starts the oil pressure switch will energize the relay and send power to the fuel pump. The oil pressure switch will then switch over to the other pole of the switch once oil pressure is constant and cranking has stopped.

I got my key on power from the power supply side of the glow plug relay. Don't use the Brown/Red Stripe wire as it is the wire the PCM sends the ground signal to the GPR.

Here is the wiring diagram I used.

 

[Tom S]

PCM does control the glow plug relay by supplying the ground. I think Dennis Schroeder was working on a controller that would let us have a SD comparible pump function.

 

[old man dave]

Mine is wired from key on engine on voltage source without any priming problems. I do have a bypass switch to run fuel pump without engine on to be able to set fuel pressure regulator without running engine or to prime entire system after fuel system work on my regulated return system.

When starting fuel pump for the first time, use the rear tank as gravity will feed prime the fuel pump. Others have reported initial priming problems, I think they were trying initial use off of the side tank.

 

[PsRumors]

First off, prime was really the wrong terminology. I meant to say build pressure prior to starting

I have installed the oil pressure switch and the truck starts just fine without building pressure first.

 

[mjonesjr]

The pressure is built instantly. There is always fuel there, so the truck will start fine. I've watched my fuel pressure gauge that is mounted on my return regulator while someone else cranked the engine on mine and it built pressure before the engine ever fired.