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

[ae2598 at wayne.edu]

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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