454 injection conversion question
 

Hi guys im in the middle of rebuilding my 454 and i decided to put injection on the old girl. i have bolted the intake down and put most of the wiring on. I got to puting the fuel pump on and im missing a hose from the electric pump to the fuel rail. This posed a question is it better to have the Cool fuel module or just run a mechanical pump?

Preformance isnt my main focus just reliability and econemy.

cool fuel will eliminate any vapor lock. another option is to route a return line back to the tank from the rail, to eliminate any heat related vapor lock.

sorry guys i have just discoverd my syestem is this one
http://www.mercruiserparts.com/Show_...nd+Fuel+Cooler

is this the 500 HP version ?

boats.net are gona make a killing off me this year :(

[QUOTE=wirlybird;3693761] This posed a question is it better to have the Cool fuel module or just run a mechanical pump?
QUOTE]

a mech fuel pump with efi?

PM sent

[QUOTE=dereknkathy;3693849]it must be a lift pump in my link above for my system

And the old version efi only had mechanical pumps im not sure if thats a typo on mercruisers behalf it sure seems strange.

fixx
 

[QUOTE=dereknkathy;3693849]reread the ?,,it states the mechanical pump and he mentioned a electric fuel pump ..the merc engine has a mechanical pump feedint the electric pump for the correwct amount of fuel pressure..the tiny pump is designed to sit in fuel not suck fuel from the tank.

so the mech pump (i assume essentially a stock pump for carbs) fills a small fuel tank the efi pump sits in?

Yep, that is the VST tank. It is best to eliminate it and just run a return line to the tank. It will save alot of headaches down the road.

the fuel filter is storage point for fuel, this is setup that develops vapor lock. running return line back to fuel tank keeps cool fresh fuel in rails, instead of recirculated heated fuel.

the mech pump fits from the tank to the filter filling the filter up. The cool fuel mod circulates through the filter and supplys the rail.

Thats the way it looks on the Diagram

Not all of the 454 MPI's use the mechanical pump, if its off a magnum it shows one in 96 -97 only, my 2000's and don't have them.