MS3X - Fuel Pump Control

[garrycol]

MS has a fuel pump control function - is this just a "safety" function so that the fuel pump only runs when the engine is running or is there something else to it.

The reason I ask is my vehicle already does this via its LPG controller and also the fuel pump does not operate until minimal oil pressure is detected (cranking is enough) so if the engine stops so does the fuel pump. I would prefer to leave this as is and if MS does not need to have control of the fuel pump use this control for something else I have in mind.

Thanks

Garry

[DaveEFI]

MS runs the pump for a couple of seconds at switch on to prime the fuel rail. Then only runs afterwards when it sees a tach signal. Relying on oil pressure only might make for a slow start-up.

What you could do is fit a series diode to the MS switched pump relay feed, so the pump relay is controlled by both the MS and LPG controller. The diode will prevent any inter reaction.

[garrycol]

Thanks Dave - the way it is set up now is fine and I dont want to play with the arrangement as it works and will require playing around with wiring under the dash - I will just not connect the MS3 to the fuel pump.

Cheers

Garry

[billr]

How about the injectors and ignition? Those are recommended to be powered-up by the FP signal (via a relay). Are you going to have those "always hot" when key-on, or tie them into the LPG oil-detect circuit too?

[garrycol]

No I will leave things like that as is with the MS and just not connect the fuel pump to MS. I was just concerned that there might have been another reason to have the fuel pump connected to the ECU.

Thanks

Garry