502MagMPI conversion to Carb
 

I have a 1996 502MagMPI. The MPI (MEFI-1 with cool fuel) system has frustrated me all summer to the point where I’m just about ready to rip it off and bolt on a Carb.
My questions are can I use the existing engine wire harness and distributor without major modifications?
I would assume the IC module internal to the distributor can do the timing advance. What do I do with the ECU? Just unplug it?
What do I need to change on the engine wire harness?
I have the carb and intake off a 1996 454Mag and from what I can tell from the Merc manuals, they were the same for the 502Mag with just different jets and spacer.
I’m hoping I just need to buy an electric fuel pump to feed the carb and be good to go.
Help Please!
I know this has been done before…
Thanks,

I had done exactly what you're trying to do but my mechanic did the conversion. I don't know the details but it wasn't that big of deal.

I'm not sure if the dist is tied to the computer or not, if so just run a aftermarket dist, elec fuel pump and you should be good to go...

Can't you use the existing pulley mounted fuel pump? EFI can be a major pain I agree.

I've read somewhere people have use the existing distributor with built in IC control module.
I rather not buy a new distributor this year; maybe next year.

My EFI just has the cool fuel high pressure electric fuel pump.

I completed the whole job you can call me and I can assist you whatever information you need . I can be reached at 203 877-7560. Jeff

The distributer has no provisions for mechanical advance as this is done completely by the computer program,you will need a different distributer but its not the end of the world,just a std hei would work then set the advance curve,Smitty

thats what I was thinking as most EFI setups manage the advance curve as well, but your fuel pump runs way to much pressure for a carb, could add a regulator but the cost and the plumbing I would just by a std elec pump and be done with it...also if you need a dist I have complete marine setup, everything I'll sell for $100 if interested and a new holley 7 psi fuel pump as well $ 50 Rob [email protected]

Yes Smitty, I know there is no mechanical advance but I thought the IC module inside has an advance curve of 15 or20° built in.
Yes, the ECU controls when it's working right. My original ECU no longer will comunicate with the IC modual but will still control the injectors. F'n black box...:rolleyes:
I know I'm being cheap guys, but I don't want to spend a bunch of cash on stuff to convert to a carb when I may just go back to EFI next year...:cool: