i will assume the memcal is what gives me the "limp home mode". if my chip goes bad does it automatically use the memccal data to run car? OK here is the confession. the 7747 came out of a V6 astro van. so the memcal is original. i have never removed it. can i burn one for my V8 or do i just pull one out of a 7747 in junk yard that had a v8? if i burn it where can i find a bin file and which one should i select? this Q came from a comment from grumpy on another post

 

A memcal is the blue doohicky in the P4 ecms. It contains all the programming and limp home mode stuff.

In the C3 ecms like your 7747, you have a Calpak and a Netres. The Calpak is the 24 pin EPROM. The Netres, is the small replaceable chip beside the calpak. Yes you want to use the Metres that most closely resembles your application.

Same with the .bin find one that most closely matches your application.

 

is this a special bin just for netres? can a blank chip be purchased and my current bin loaded onto it for back up so to speak? or do i find one from junkyard out of v8 7747 truck?

 

Netres means Network resistor. There is nothing to burn, it's a set of resistors, that put into play an Analog strategy so the ecm can get you home in the event of a processor failure.

Actually you have normal, soft fail, and limp home mode. Thou people often lump, soft fail and limp home into the same thing.