A little too simple

[EFISYSTEMS at aol.com]

Hi Bill,
    The first thing you want to do is verify the Throttle bores to be the same
as a 350...but you will at least have to change the injectors....The 4.3,5.0,
and 5.7 all have different injectors,,,,this should fix your major lean
problem...hth's
-Carl Summers


In a message dated 2/6/99 9:49:12 AM Pacific Standard Time, Onebil2mny at aol.com
writes:

<< Subj:	 A little too simple
 Date:	2/6/99 9:49:12 AM Pacific Standard Time
 From:	Onebil2mny at aol.com
 Sender:	owner-diy_efi at efi332.eng.ohio-state.edu
 Reply-to:	diy_efi at efi332.eng.ohio-state.edu
 To:	DIY_EFI at efi332.eng.ohio-state.edu
 
 First, I would like to introduce my self..  I'm Bill, and I'm a caraholic.
 
 I am currently working on a 56 BelAir conv with a production line LT4 using a
 GM ECM from Howell, 700R4 tranny, and all kinds of other non list related
 mods.   I am also building (for my self, the BelAir is for my Father) a 72
442
 conv. LS-6 crate motor with a Roller Hydraulic cam, Wiand Team G with
injector
 bungs, Kinsler throttle plate and an Accel ECM. It also has several dozen non
 list type mods. I think this list may be a little advanced for me, as I'm
only
 an ASE Master Tech, and don't have a Bachelors degree in anything.  I've been
 following a couple of the posts lately, and I don't know a thing about
burning
 proms, much less building a device to modify OBD2 ECMs!
 
 Anyhow, here is my query.....   I have installed a TBI motor from a 91 Chevy
 Truck in to a 85 MonteCarlo.  The Monte was originally equipped with a TBI
 4.3L.  I have installed a 91 Caprice ECM & Prom (ECM service # 16136965) and
 on the monitor everything seems OK, except for the MAT as the Monte was not
 originally equipped with one.  I will install on soon as I have the pin outs,
 sensor and sensor pig tail....  I just need the terminal at the ECM.  My
 problem is what appears to be a terrible lean condition.  I am using the
4.3's
 throttle body as I was advised it should keep up.  It does appear to have the
 same size throttle bores, and I can only assume injectors are ok....  at
least
 for Idle!  Anyhow, I have checked for the obvious, vacuum leaks, etc. but it
 still runs lean, hesitates, backfires, etc.  That is until I dead head the
 fuel pressure.   If I pinch off the return line, it runs fine.  I have 12 psi
 at idle, in spec for a 85 car, but I don't know the proper pressure for a 91.
 Could low pressure be my problem?  Does a 91 Caprice TBI require a higher
fuel
 pressure?  Or, is there something wrong with my choice of ECMs?  Any
 suggestions would be great!
 
 
 Thanks for the help. and sorry if this is a little too simple.
 Bill (feels so uneducated) K
 
  >>