Re: Engine swap computer & wiring question

[Shannen Durphey <shannen@grolen.com>]

I shoulda recognized your name right away.

Well, I'd use the ecm from the 91 Z.  The number on it is probably
1227730.  It's used in Camaro's with 8 cyls, and lotsa 6 cyl cars, so
lots of 'em around.  Sunbird VSS for regular dash is cable driven in
88.  I know, mine bounces on cold mornings.  Makes 2000 pulses per
mile. If the Z's have a non- digital dash , it will be the same
sensor.  4 cyl ecm is different, further it's different for
chev/pontiac engine, early or late turbo, tbi or pfi engine. 
Basically, toss it.  SFI is extra work, nice to say you've got it but
not a key element in winning a race.  "SFI= more power" is not the
whole story with factory engines.  You _need_ to get reliable wiring
diagrams for your car and engine, and another one for the z24 that
your "chip" is from.
Using the old chip:  There are lots of updates to the proms.  What are
the four letters/numbers on the chip (like ARUN/9039)?  I can see if
it's a current version.  Some of the driveability bugs that the
updated proms fix are buggers to live with.

Unless you like a serious challenge, forget the OBDII idea.  If you
just want the car to run, you might be able to fudge a stock 3.1
calibration, play with fuel pressure, and make it go.  To get the
most, better decide now to get into reprogramming it yourself. 
Anybody who's serious about performance should be into tuning their
own cars.  Few "generic" chips that I've seen are really good, and
some are pure BS, IMO.  A side benefit is that you'll have enough
experience after tuning the 3.4 to start tuning your buddies' cars.

I would also seriously consider using a set of 3.1L heads and intake
if possible.  Most of the "wowie" for the 3100 and 3400 were in these
parts, and yes you would be tossing that.  The tradeoff would be
getting an intake and heads that will support all the
brackets/ducts/hoses that are already in the J cars.  Trust me, in an
engine swap the smallest problems can easily become big, expensive
headaches.  If you've got good fabrication skills and tools then you
can figure those headaches out on your own.  But if you're into your
first swap it's better to play it safe.  Once the engine swap bug
bites, you'll get plenty of "do overs".

First step, IMO, get the wiring diagrams and start making
comparisons.  Make plenty of trips to the junkyards, too.  
Shannen Durphey

57 Chevy pickup, 302 Crossfire
67 Chevelle, LT4 copy, pfi'd next week
79 Monte Carlo, 455 Buick and rust
86 Toyota 4X4, more diamond plate than one man should own
88 Sunbird Convertible 2.0
93 Cavalier 2.2
And they're all due for oil changes!
----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo@lists.diy-efi.org