Help with Ecm V Mac II ? E7 350

[dexter860 3]

Ecm went out of my 95 Ch 613 , E7 350, borrowed an ecm from shop to get home , found a place in Texas that "thinks" they can repair mine , but most places have never seemed to work on these older ecms. Mine only has one big box on passenger side under glove box , we took the one out of our 96 and it has the big box and a smaller box that says Bosch on it , and they have different connections, so that didn't work. Can't find any used ones anywhere my part # is 12MS54M5, the one I'm using is 12MS54M7. I find alot of the ones with the number ending in M7 but no M5, I wonder what the difference is , the one I'm using now is an M7 , it seems ok but my speed is off and truck seems to surge a little more at idle, I think mine is a vmac 2 , but not sure , can I swap a box out of a 427 , into a 350? Dealer says new one is nla.

[Mackpro 326]

In 1995 VMAC 1 ( 2 ECM) and VMAC 2 (1 ECM) as well as mechanical engines were available.  Yours is a VMAC 2 .  The ECM’s are no longer available new or Reman. The part numbers are still in the system but no stock anywhere. Your M5 ecm was the first version the it superseded to a 56M6 then 59M7 then M8 then on through 3 Volvo part numbers . A dealer should be able to reset the tire size and gear ratio to match your truck as the ecm is still going off programed data of the truck the ecm came out of. 

[dexter860 3]

Thank you for the reply, that's good information , I wonder how much better fuel economy the v Mac II vs the mechanical pump of the same engine then would be?

[LilMartian 2]

There was a company in Tyler, tx that was repairing vmac ecms and I can’t find number on line now but showing in eBay several m7 modules. Also an option, possible slim one, is check with DEX used parts, this is the Volvo/Mack used parts department. You can find them( I have 2 vmac 2 ecms and nope, don’t ask, one has an rpm issue around 1700, thanks Nick, and the other is my bestest test ecm, sorry) at several bone yards and such. Check with tony at Turbys used truck parts in vina,al. He didn’t have one a week ago but he gets trucks in all the time. Just tell him a Martian sent you. 

[dexter860 3]

Ok thanks