as seen in the instuctions its the same cable used on the obd1 stuff all you need is serial and a ground crossover your obd1 scan cable. I tried to find the post but i think it was on monodax long ago that indeed the obd1 cable was same to flash as the obd1 LT1 stuff.
I was asked several weeks ago where to find Datamaster for MEFI. I've had this on my laptop for years but I'm not sure if they support it any more.
Also, here's a list of pinouts that was posted to Monodax years ago.
MEFI CONTROLLER CONNECTIONS
MEFI 1
J1 Connector:
J1-1 Knock Sensor Input
J1-2 Coolant Temp. Sensor Input
J1-3
J1-4 I/O Fluid Level Switch
J1-5 Master/Slave (twin engine application)
J1-6 Oil Pressure Switch
J1-7 Diagnostic Output (blink light)
J1-8
J1-9 MAP Sensor Input
J1-10 TPS Sensor Input
J1-11 12V Ignition
J1-12
J1-13 Sensor Ground
J1-14 ECM Ground
J1-15 5V Sensor Reference
J1-16 12V Battery
J1-17
J1-18 Serial Data
J1-19 Water Flow Switch
J1-20 Oil Level Switch
J1-21 Emergency Stop Switch
J1-22 Trans Temp / Trim Set
J1-23
J1-24 Intake Air Temp. Sensor Input
J1-25 Trim Sensor Input
J1-26
J1-27
J1-28
J1-29 Sensor Ground
J1-30 ECM Ground
J1-31 5V Sensor Reference
J1-32 12V Battery
J2 Connector
J2-1
J2-2
J2-3
J2-4
J2-5 Injector Driver
J2-6 Distributor Reference Low
J2-7 Port Fuel Jumper
J2-8 Distributor Reference High
J2-9 Fuel Pump Relay Driver
J2-10
J2-11 Coolant Lamp Output
J2-12 RPM Reduction Warning Buzzer Output
J2-13 Idle Air Control Coil A Low
J2-14 Idle Air Control Coil B High
J2-15 Fuel Injector Ground
J2-16
J2-17
J2-18
J2-19
J2-20 Fuel Injector Ground
J2-21 Fuel Injector Driver
J2-22 Port Fuel Jumper
J2-23 Ignition On Control (Spark Out)
J2-24 Ignition Bypass (For Timing Set)
J2-25
J2-26 I/O Fluid / Water Flow Lamp Output
J2-27 Oil Pressure Lamp Output
J2-28 Idle Air Control Coil A High
J2-29 Idle Air Control Coil B Low
J2-30 Oil Level Lamp Output
J2-31 Malfunction Indicator Lamp Output
J2-32
MEFI 2 Controller Pin Outs
J1 Connector:
J1-1 Knock Sensor Input
J1-2 Coolant Temp. Sensor Input
J1-3
J1-4 I/O Fluid Level Switch
J1-5 Master/Slave (twin engine application)
J1-6 Oil Pressure Switch
J1-7 Diagnostic Output (blink light)
J1-8
J1-9 MAP Sensor Input
J1-10 TPS Sensor Input
J1-11 12V Ignition
J1-12
J1-13 Sensor Ground
J1-14 ECM Ground
J1-15 5V Sensor Reference
J1-16 12V Battery
J1-17
J1-18 Serial Data
J1-19 Water Flow Switch
J1-20 Oil Level Switch
J1-21 Emergency Stop Switch
J1-22 Trans Temp / Trim Set
J1-23
J1-24 Intake Air Temp. Sensor Input
J1-25 Trim Sensor Input
J1-26
J1-27
J1-28
J1-29 Sensor Ground
J1-30 ECM Ground
J1-31 5V Sensor Reference
J1-32 12V Battery
J2 Connector
J2-1
J2-2
J2-3
J2-4
J2-5 Injector Driver
J2-6 Distributor Reference Low
J2-7 Port Fuel Jumper
J2-8 Distributor Reference High
J2-9 Fuel Pump Relay Driver
J2-10
J2-11 Coolant Lamp Output
J2-12 RPM Reduction Warning Buzzer Output
J2-13 Idle Air Control Coil A Low
J2-14 Idle Air Control Coil B High
J2-15 Fuel Injector Ground
J2-16
J2-17
J2-18
J2-19
J2-20 Fuel Injector Ground
J2-21 Fuel Injector Driver
J2-22 Port Fuel Jumper
J2-23 Ignition On Control (Spark Out)
J2-24 Ignition Bypass (For Timing Set)
J2-25
J2-26 I/O Fluid / Water Flow Lamp Output
J2-27 Oil Pressure Lamp Output
J2-28 Idle Air Control Coil A High
J2-29 Idle Air Control Coil B Low
J2-30 Oil Level Lamp Output
J2-31 Malfunction Indicator Lamp Output
J2-32
MEFI 3 Controller Pin Outs
J1 Connector:
J1-1 Fuel Injector Driver A
J1-2 Ignition coil
J1-3 REFLO
J1-4 ECM Ground
J1-5 ECM Ground
J1-6 EGR
J1-7 CKGAGE/GOVOVS
J1-8 RPMCNG
J1-9 MALF Lamp
J1-10 EST
J1-11 IAC Coil B High
J1-12 IAC Coil A Low
J1-13 N/C
J1-14 Knock Sensor 2
J1-15 N/C
J1-16 N/C
J1-17 Injector Driver B
J1-18 EGRIGN
J1-19 O2 Sensor Low
J1-20 ECM Ground
J1-21 GW1LMP/TROLLMP/CNP
J1-22 GW1LMP/TRAN/GOV
J1-23 Fuel Pump Relay
J1-24 BYP
J1-25 Oil Level Lamp
J1-26 Warning Buzzer
J1-27 IAC Coil B Low
J1-28 IAC Coil A High
J1-29 N/C
J1-30 Knock Sensor 1
J1-31 N/C
J1-32 Serial Data
J2 Connector
J2-1 Battery
J2-2 N/C
J2-3 Sensor Return
J2-4 5 Volt Reference
J2-5 ESTOP
J2-6 BOOT
J2-7 Oil Pressure Switch
J2-8 GW2/GOVMOD
J2-9 Load1/Shift Interrupt/LOCKLO
J2-10 Distributor Reference
J2-11 Coolant Temp Sensor
J2-12 Fuel Pressure Sensor
J2-13 N/C
J2-14 N/C
J2-15 N/C
J2-16 O2 Sensor High
J2-17 N/C
J2-18 Sensor Return
J2-19 5 Volt Reference
J2-20 Load Anticipation
J2-21 Master/Slave
J2-22 Diagnostic Test Terminal
J2-23 Oil Level
J2-24 GW1/FCAL
J2-25 VSSVF
J2-26 TPS Sensor
J2-27 MAP Sensor
J2-28 EGRFB
J2-29 OILP
J2-30 MAT Sensor
J2-31 ESC
J2-32 Ignition Power
MEFI Read/Program Connections:
To read or program the MEFI1 and 2 controllers, you need to make the following
connections:
J1 – 11 Ignition
J1 – 14 Ground
J1 – 16 Battery
J1 – 18 Serial Data
J1 – 30 Ground
J1 – 32 Battery
To read or program the MEFI3 controllers, you need to make the following
connections:
J1 – 4 Ground
J1 – 5 Ground
J1 – 32 Serial Data
J2 – 1 Battery
J2 – 32 Ignition
RS232/MEFI Converter
The RS232 to MEFI converter used to connect a PC to the MEFI controller for
reading and programming is the same converter as that used for the ‘94/95 LT1
PCM.
1project2many,
Thank you for the updated information!
I think I'll make an adapter plug MEFI / ALDL and see if I can communicate with the MEFI 3 / MEFI 4 computer (I don't know which type it is) that is in the Cadillac. The vehicle is about 70 miles away, so it might be several weeks before I get out that direction.
dave w
anyone working on adx and xdf for this have a mate just cammed his boat on engine builders advice and now the ecu is having a sad LOL 7.4L bbc mercruser
So whats the deal with the e67 ecus?
Supposedly MEFI5 is the E67 with a different OS.
What kind of secret sauce does mefiburn use? Sounds like the MEFI is a hell of an ecu. can run cable or dbw, 24x or 58x, distributor even..
I just bought a 1969 Vdrive flatbottom and has a mercruiser 7.4 it has a mefi I'n it ill be tweaking it here in a few weeks on the water
Last edited by roughneck427; 04-23-2014 at 10:18 PM.
thats the same engine we have
Originally Posted by delcowizzid
My friend has mefi burn and going to test it out ive never tuned one before and from what I hear its all injector bpw and no ve. I have a mefi 3 controller on it from what I can see im not sure if im going to run it as I looked at the return system of the fuel lines they dumped it back to the suction side of the ext fuel pump I don't know how it affects the tuning ill install a fuel gauge and see what it looks like this weekend in the driveway. What camshaft did you guys run??
Well I decided to just buy mefi burn myself. I talked to the owner and nice guy should have it in a couple days ill post the file that I read out.
i dont think you can read out the tune can you.i heard the ecm's are locked from factory and that you have to flash a new tune in to begin playing
When I talked to Bob he said when I get the cable try and read it out it will give me a checksum number and he has all the passwords for the mercruiser mefi stuff. I had asked him the same thing he said not an issue
I got tts datamaster posted above working using an LT1 cable and a crossover connector
Last edited by roughneck427; 04-30-2014 at 12:13 AM.
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