Big_Baller

Has any one made the switch from MEFI to AEM Infinity? Currently I am running a 575sci with Eddie Youngs fuel injection plate but also running the AEM cd7 dash and very familiarly with AEM ECM from my automotive projects. The ability to make tuning changes with out having to learn mefi burn would be ideal. I know AEM has a MEFI4 to Infinity harness but does anyone know the differences between mefi3 and 4 engine harnesses ? Is it worth buying the conversion harness and repining? or just buy (make) a big block chevy Infinity harness ? Thanks in advance. If interested build thread is below.

24' Outlaw 575sci Build

-Nick

articfriends

iTrader: (1)

years ago we repinned a mefi3 to mefi4, years later we repinned it from mefi4 to mefi3, it can be done. No personal experience with the aem ecm though, Smitty

Big_Baller

Ah very cool, was not sure if it was possible. Any chance you still have pinouts diagrams for each ? or where to find online ?

green lightning

Nice build what lakes do you boat on ?

Big_Baller

just local lakes in upstate NY. Lake George and sacandaga.

green lightning

Nice just wanted to know never saw the boat before , I boat on Oneida and 1000 Islands area .

articfriends

iTrader: (1)

there was a site called "michaels tractors" that had mefi pin outs at one time

Big_Baller

articfriends thanks for the tip I pulled the Mefi 3 pinout from there and found mefi 4 elsewhere. Posted up incase it helps someone else. Will post more when I start the repining, since I have a harness between the infinity ecu and engine harness ill just re-pin the conversion harness to work with my mefi3 engine harness so I can do the work outside the boat.

MEFI 3
Raw link : Michael's Tractors (Simplicity and Allis Chalmers Garden Tractors) - Mercruiser MEFI-3 ECM Delphi 16237009
MEFI-3 ECM Connectors:

The front of the MEFI-3 ECM has two connectors, J-1 and J-2. These are 32 pin connectors of two rows of 16 pins; these have a slight offset between the top and bottom rows of 16 pins. (I am looking to get the connector type for this.)



The J1 Connector
J1-1 Injector Driver (cylinders 2,3,5,8)
J1-3 Ignition Control (Ref. Low)
J1-4 ECM Ground
J1-5 ECM Ground
J1-9 MIL Lamp (DLC pin E)
J1-10 Ignition Control Signal
J1-11 IAC "B" High (Idle Air Control)
J1-12 IAC "A" Low
J1-14 Knock Sensor Sign (only used on 7.4 MPI)
J1-17 Injector Driver (cylinders 1,4,6,7)
J1-20 ECM Ground
J1-23 Fuel Pump Relay Driver
J1-24 Ignition Control Bypass
J1-26 Audio Warning Horn
J1-27 IAC "B" Low (Idle Air Control)
J1-28 IAC "A" High
J1-30 Knock Sensor Signal
J1-32 Serial Data (DLC pin G)

The J2 Connector
J2-1 Battery
J2-3 TP and IAT Ground (Intake Air Temperature)
J2-4 TP 5V Reference (throttle position)
J2-7 Discrete Switch (oil pressure switch)
J2-8 Discrete Switch (transmission overtemp switch)
J2-10 Ignition Control Ref. High
J2-11 ECT Signal (Engine Coolant Temperature)
J2-18 MAP Ground (both MAP and ECT ground)
J2-19 MAP 5V Reference
J2-20 Discrete Switch Signal (neutral saftey/Load Anticipation)
J2-21 Master/Slave (DLC pin H)
J2-22 Diagnostic Test (DLC pin B)
J2-24 Discrete Switch (Gear lube bottle on L29 only)
J2-26 TP Signal (throttle position sensor)
J2-27 MAP Signal
J2-30 IAT Sensor (Intake aire temp)
J2-32 Ignition Fuse

MEFI 4

Link: Mefi 4 Pinout