Re: Mods to '85 GM TPI ECM

["Jim and Sharon Brady" <bradyiii@shore.intercom.net>]

Shannen,
     I know the '85 is the rarest of the TPI ECM's.  If worse comes to worse
I would upgrade to an '87 harness but I would like to keep what I have for
simplicity's sake.  I'll look over your suggested readings.  I'll also get
you my broadcast code.  I'm pretty certain it is and '85 since it has the
Bosch MAF burn-off piggy back module.  That was only used in '85 right?
Thanks.

Jim Brady

> Hello, Jim Brady.
>
> If you can get the Broadcast code from the Eprom, I can confirm the
> year/make/model your computer is from.  The BCC is a combination of
> letters and numbers usually on a sticker on the chip or it's holder
> inside of the ecm, and will look something like HLM 3800 or HLK 2315,
> or even ARAP 4194.  Some of the recommendations will depend on what
> year ecm you actually have.
>
> If you don't have a good scantool, it's a good idea to get one.  I've
> seen them for sale at Sears for cheap $$.  The scantool will allow you
> to read diagnostic information from the ecm.  To read the eprom you'll
> need an eprom burner, several are available from web sources.  To burn
> new chips, you'll also need an eprom eraser.
>
> Manipulating data, the heart of the issue.  To determine what can be
> changed, you'll need to know what year ecm you have.  There's bunches
> of info about the 86-89 TPI ecm, and also about the 90-91 MAP based
> ECM.  I've seen little on the web about the 85 model. : (  You might
> consider changing ecm's if it turns out that you do have an 85 model.
> The easiest way to make changes is with specially written software,
> which can interpret the data from the chip and present it in more
> human numbers.  There is some free stuff for 86-91 tpi's which isn't
> too bad.  You can also purchase software, but you'll need to know what
> year/bcc you have.  Again, lots of people are working with the 86-89
> and 90-91 tpi ecm's, so using one of those computers will allow the
> "been there done that" guys to help you in a jam.
>
> Generally, the error codes can be turned on/off, fuel parameters can
> be changed, and timing tables can be manipulated.  There's more, but
> for "get your feet wet" tuning, it's easy to change too many things
> too fast, and end up with big problems.  Some required reading:
> ftp://diy-efi.org/incoming/TuneTip1.txt
> ftp://diy-efi.org/incoming/GM_ECMArchives.zip
> ftp://diy-efi.org/incoming/DIY_EFIArchives.zip
>
> The DIY... archives are loaded with info, waaay too much to absorb on
> the first two or three readings.  Look for programming 101 for a
> heading, for a start.  TuneTip1 is a good guideline for chip tuning,
> and the ECM archives will have some info in various places.
>
> Didja get enough to start with? : )
> Shannen
>
>
> Jim and Sharon Brady wrote:
> >
> > Hi, my name is Jim Brady and I just joined the list a few moments ago.
My
> > current project is my '87 Monte SS.  My Monte is equipped with the GM
> > TPI(Tuned Port Injection) system consists of an '85 computer(I assume I
have
> > an '85 computer because it had a Bosch MAF burn-off box attached to it)
with
> > '87 hardware.  My original motor was a 305 and the system worked
perfect.
> > My new setup is a 383(stroked 350) with a T56 manual trans.  The only
> > changes I have made to the system since I upgraded from the 305 to the
383
> > is 24lb/hr injectors and a fuel pressure regulator.  Everything works
great
> > except full throttle.  I understand full throttle switches the ECM to
open
> > loop mode leaving the EPROM to feed the system pre-determined values.
Aside
> > from improving my full throttle condition I would like to monitor the
> > parameters of the running motor.  What do I need to approach this
project?
> > I assume an EPROM burner, cable for the aldl connector and software.
What
> > can I manipulate with the software?  How about the EPROM.  I am new to
this
> > and would appreciate any help you can give on this matter.  Thanks.
> >
> > Jim Brady
> > '87 Monte SS 383 TPI 6 speed
> >
>
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