i was hoping to find out if an ECM off of a 1996 7.4 efi mag would work on a 1999 7.4 efi mag . thanx Rob

1996 is a MEFI 2 case with MEFI 1 software..
1999 is a MEFI 3 case..

The pins are in different locations...
So I am saying NO...

Speed girl is right,,, they are different Gen motors,,, wont work.

thanx Rob

Thanks Rob!!!!!!!!!
What am I chopped Liver...

I knew the answer he just aggreed with me....!!!!!!!!

And who the heck is Rob !!!???

OK smarty pants, so whats the difference between the MEFI 1, 2, and 3. What years for each. Advantages and disanvantages.

First: The cases are different...
Second: Pin placement are the same on 1 and 2 but different on 3...

MEFI 1 has 9 fault codes
MEFI 2 has 16 fault codes
MEFI 3 has 23 fault codes

MEFI 1 is 1993 GM software
MEFI 2 is 1996 GM software Merc didn't use till 1997
MEFI 3 is 1999 GM software...

Pros and Cons: All three systems work on speed density. The more fault codes the easier to diagnose a problem.


Any other questions..

thank you speedgirl your knowledge is unmistakingly amazing by the way i am Rob guess i didnt use the proper technique so everyone would understand

thanks, Rob ( < thats my name )

see what trouble leaving that little comma out will cause ya !!! Nice to meet you Rob !!!

Dennis