Re: 92 LT1 chip and computer

[Roger Heflin <rah@horizon.hit.net>]

On Mon, 10 Jan 2000, Carl Summers wrote:

> Hi,
>    I have a 92 LT-1 Corvette here and was looking at the computer and
> prom....it appears to be a 1227727 computer but has a part number of
> 16159278 on it....same plugs as a 727 so am assuming it is an updated
> service number...can anyone verify????  The prom is a 27256 like a 727 but
> code is completely different....I am assuming this is because of SEFI
> instead of bank fire?????  Also noticed there are no resistor packs under
> the esc module on the mem-cal.....I guess my question really is....if this
> is a 7727 then am I correct in assuming any 7727 computer can be made
> sequential with pinout changes and ignition signal changes???? can a 7730 be
> changed as well or are there not enough pins????? Anyone have any experience
> with this????? Thanks
> -Carl Summers
> p.s. anyone playing with any 2 or 3 bar stuff for this computer?????<G>
> 
> 

See http://www.hit.net/~rah for info on the 93 Z28 LT1 computer
(should be almost the exact same computer, appears to be a 68HC11F1
based computer).   I have parts of the eprom disassembled with what I
know on the web site.

The 92-93 LT1 computer is batch fire, ie it fires each side different,
but all injectors on a side fire at the same time.

The code for the 92-93 LT12 also uses a optispark rather than a normal
distributor/crank tirgger setup so that is different, and may account
for some of the code being different.  Also from looking at the older
computers there is alot more code than was in the oldercomputer so
maybe GM had more things they thought they could do and since they had
more memory/experince or whatever they did it.




				Roger