Re: Engine swap computer & wiring question

["Programmer" <nwester@eidnet.org>]

Didn't the early 90's Z34 run a 3.4L DOHC OBD1 ??

-----Original Message-----
From: Tim De Coster <craz1@softhome.net>
To: gmecm@diy-efi.org <gmecm@diy-efi.org>
Date: July 12, 2000 2:39 PM
Subject: Re: Engine swap computer & wiring question


>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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