Re: Engine swap computer & wiring question

["Tim De Coster" <craz1@softhome.net>]

See below for comments:

> Can you get a 3.4L computer that's not OBD2?  If you look at
> www.cruzers.com/~ludis you can probably get a non OBD2 ECM part number.

No, to my knowledge there are no applications where a 3400 was ever run by
an OBD1 computer.  After looking at that website, it came to me that the
Beretta had the 3100 in '94 *I think*, and there was a number for '93-'96
3.1 with SFI.  This tuning would be more likely to work with the 3400,
because on the 3100 and 3400, literally the only difference is the
displacement.  Both were SFI.  This may be a possibility.  I'm not sure,
however, if the EPROM from this Beretta would fit right into my existing
computer or if I would have to get the entire Beretta computer.

>
> > control this new engine if I get a new EPROM module for it?  I already
have
> > one from a '91 Z24 (It had a 3.1 v6), and I am hoping that it will work.
It
> > may because the 3.4 is basically the same exact engine as the 2.8,
except it
> > has revised heads, among a few other things.
>
> Larger displacement also.  Is the 3.1L ECM the same as your 2.8 ECM?
> same type trans? same type VSS?  BL can probably stretch to cover the
> increased displacement but you'd rather have a 3.4L calibration.
> replacing memcals etc. is all about tuning, so if you want a tuning
> project in addition to a swap project then you can try it.  I think the
> least risk path is to find a 3.4L ECM that will work.  Either the OBD2
> one, if you can dummy up some O2 sensors and whatever else it wants, or
> a non-OBD2 3.4L ECM that matches what you have option wise as close as
> possible (trans type, VSS, etc.)  If the 3.4 ECM is the same part # as
> your existing 2.8L ECM then I guess you can get away with just a 3.4L
> cal in your 2.8L ECM.

The 2.8 and 3.1 MPFI version engines are identical other than displacement
(different crank and connecting rods).  I know people who have changed to a
3.1 from a 2.8 without touching the computer.  One of my concerns with the
OBDII computers is compatibility with  my dash, and another is the PASSKEYII
systems that they seem to be intertwined with.
>
> >
> > I know that the Cadillac Cimarron's digital dash does talk to the ECM,
> > because I was going to put the Cimarron digital dash into my Sunbird...
> > until I found that most of the info. for the gauges goes through the ECM
> > before it gets to the dash.  This probably would mean that the Cimarron
> > wiring idea is out of consideration, right?  The only reason I thought
of it
> > was because the dash is physically the same in it, and it has a 2.8 mpfi
v6
> > engine.
>
> Cimarron dash would require a Cimarron ECM for the gauges to work.
> Cimarron ECM is 2.8L only?  Getting a Cimarron dash, ECM, wiring etc.
> would swap in nicely (assuming you can make the dash stuff fit), but now
> you've got some calibration work probably to make it work right.  Your
> displacement is 20% more now.

Yep, I would get the whole works.  The Sunbird and Cimarron dashes have the
same openings, mount the same way... everything.  The '87-'88 Cimarron
dashes are 2.8 only.  They stopped the Cimarron in '88 (thank God).
>
> Personally, I'd leave the digital dash project for stage 2, and get the
> car going now w/some kind of 3.4L ECM

he hee... I already sold that digital dash.  I want no part of it : )


Tim De Coster
'89 Z24 Conv.
'88 Sunbird GT Conv.
'98 Intrepid
www.sunbirdconvertible.com



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