Possibly OT, ??s about a GM feedback Q-jet

[Diane Stowe]

there might be more than one model of 'computerized' quadrajet. The one I am
speaking of had a 4 pin connector on the top of it.

The Rochester book goes into excellent detail. I think I just shipped it
off.
but you can read it at Barnes and Noble or something. I think if it were all
intact it would run ok.

Diane
----- Original Message -----
From: <ae2598 at wayne.edu>
To: <gmecm at diy-efi.org>
Sent: Friday, March 09, 2001 7:09 AM
Subject: Re: Possibly OT, ??s about a GM feedback Q-jet


> Makes sense, as currently it IS running uncortrollably rich. Apparently
> the wiring was hacked enough to prevent the ECM from doing its job in the
> present state.  I have another carb I'll try throwing on there
> (non-feedback) to see if it performs any better.
>
>  On Thu, 8 Mar 2001, Diane Stowe wrote:
>
> > as far as the carb goes, it will idle uncontrollably rich without it's
ecm
> > controlling the primary metering rods, I think they just pull up if
there is
> > no ecm connected.
> > I had to use one like that without an ecm for a few days.
> >
> > when it was all working it wasn't that bad. I just gave away my manuals
but
> > I did see good explanations of what was supposed to work etc.
> >
> > Diane
> >
> > ----- Original Message -----
> > From: <ae2598 at wayne.edu>
> > To: <gmecm at diy-efi.org>
> > Sent: Thursday, March 08, 2001 7:24 PM
> > Subject: Possibly OT, ??s about a GM feedback Q-jet
> >
> >
> > > I'm kinda at a loss to figure out exactly what I have here, so I'm
turning
> > > to you guys for advice.  The vehicle is an '85 K5-Blazer, with a
> > > computer-controlled (somewhat) Q-jet.  I got it for cheap because the
gas
> > > stations that worked on this thing in the past apparently couldn't
figure
> > > out what to do with it (other than replace everything underhood!) and
it
> > > still runs lousy.
> > >
> > > The first thing that I find odd is the HEI distributor.  It has
advance
> > > weights and a vacuum can.. In fact, the only way in which it differs
from
> > > the "standard" HEI is the use of a 5-pin module, and an extra harness
> > > hanging out the back.  The pickup coil apparently feeds a signal to
the
> > > ECM as well as the module.. probably a timing reference signal.  This
> > > harness has been butchered by previous repair attempts, and probably
isn't
> > > giving much data to the ECM anyway.
> > >
> > > The next thing that's not exactly right (IMHO) is the carb itself.  It
has
> > > a M/C solenoid, but no TPS or IAC.  Every description I read about the
C3
> > > Q-jets shows at least the M/C and TPS, and usually an idle air
control,
> > > too.
> > >
> > > The ECM seems a bit un-sophisticated.. It is in a very small package,
and
> > > has a single connector with only 7 wires connected!  No ALDL that I
could
> > > find, and no provisions for a PROM.  The service number is 16042121.
> > >
> > > Anyway, what I would like to do is make this a non-computerized motor.
> > > The distributor seems easy enough, I'll just plug in a 4-terminal
module
> > > and all it a day.  As far as the carb, what will be the result of not
> > > connecting the M/C solenoid?  Are these carbs capable of metering fuel
> > > without the help of the ECM, or should I just find another Q-jet?
> > >
> > > Anyone with ideas to share on this would be appreciated..  the carb
seems
> > > to be dumping way too much fuel into the motor at this point, and I'd
like
> > > to solve this as cheaply as possible!
> > >
> > >
> >
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