elesone

I have a memcal out of an 89 Olds 3.8 MFI BCC APTF. Since it looks identical to the 7730 memcal I want to know if any V6 memcal that looks like the attached pic, can be jumpered (pins 56 &62) and use a reprogrammed chip to suit the motor in use.

Some usage will be the TPI/7730 or 7727 and 93 LT1/16159278. I have a friend that picks scrap cars and tells me when he gets a GM car so I verify the ECM. No F-body yet but a few J-body and W-body cars. So the V6 memcal is available.

In summary, can I modify any V6 memcal that is similar to the pic? If not why not.
Thanks.

RBob

iTrader: (1)

Yes you can. Although the knock filter frequency will be off.

Most of the MEMCALs use a '256 kb EPROM. Some of them are '128 kb EPROMs, they won't work with the $8D code mask.

The truck PCM MEMCALs use a '512 kb EPROM.

RBob.

elesone

Thanks RBob - I plan to unsolder the stock chip and replace it with a 512 chip I got from Moates whether it's soldered or adapted. But you say that just jumping 56 & 62 pins is not all that's required and just using the proper knock sensor may still need fine tuning. What is required?
Shows my lack of understanding of what I read. I thought that jumping the pins, using a 512 chip and burning the proper program for the set up would be the same as if I had the proper chip with the stock bcc.
My assumption: Stock memcal with AUJP is the same as V6 memcal with jumper and 512 chip burnt with AUJP. If the assumption is wrong, what can be done? I have six of these V6 memcals that I thought I could use.
Again thanks for the reply.

RBob

iTrader: (1)

Depends upon how you look at it. You can easily make the code in the PROM match up. But the knock filter won't match up. They are different for every engine. Will it still detect and report knock, most likely.

There is also the limp mode calibration. Although with a Flash chip in place of an UV EPROM that won't matter as much.

RBob.

elesone

Pardon me for being slow. Based on your last statement "Although with a Flash chip in place of an UV EPROM that won't matter as much.", I can try using the V6 memcal with the jumper as long as I use the flash chip with the right bcc.
I'm gonna have to search for some threads with similar application.
I appreciate the help RBob and thank you all for your understanding.

RBob

iTrader: (1)

The reason that the limp mode feature isn't as important when using a Flash chip is reliability. UV EPROMs can have a bit-flip. That is the well can only stay at a 0 bit value for so long until it flips back to a 1 bit (erased state).

Flash chips don't have this issue nearly as much. Some have data retention of 100 years.

RBob.

EagleMark

Really? Hmmm... have you ever seen one flip in a vehicle?

To the OP. There are three parts in a Memcal, the chip, the Netres chip and the knock Module. So if you change the chip to a programmable you have only fixed one of three. It is the one that makes it run though...

RBob

iTrader: (1)

Folks have posted here about EPROM/MEMCAL failures. I've seen bit-flip in EPROMs from years ago in PC's (I worked for Commodore). It is a known in the industry, hence the reason for checksums in BIOS chips and ECMs.

One interesting fact I researched is that when GM went to Flash chips, limp mode went away. Can't guarantee that for every Flash based GM ECM. But it is true for many of them.

RBob.

elesone

I'm totally convinced I know so very little about the subject of ECM/Prom reading your replies. But I only do it as a hobby on my hot rod in my retired years. Again, thanks to you guys, because without your knowledge I would not be installing the 3rd gen TPI in my 36 Chev. As I stated in my 1st post, my next project is the 93 F-body LT1 for the same car. I'm 66 and love doing this.