Low Idle w/ Saturn tuned port EFI.

[Jemison Richard]

Shannon,

Thanks for the input and no I don't have access to a scan tool at this time
(I have no idea which one would even connect up to a Saturn ECU).

The adjustment I speak of the initial adjustment on the plunger.  The
instructions that came with the unit specifically stated that the plunger
being extended > 1" (could have been 1.1 - whatever)  could damage the unit
and stated to check this value and adjust as necessary.  I was right on the
limit as it came out of the box and so did not adjust the unit at all.  

I've always heard that the IAC "kicks" the idle up to compensate for varying
conditions (temp, accessories, etc).  What I saw was with no IAC control the
idle was about 2500.  With the IAC it dropped to like 500 rpm (and yes this
is a problem as I cannot run my air or the car will die and the car barely
runs at the current idle).  So, I reasoned that the IAC was actually (in a
controlling manner) adjusting the idle as necessary from some initial high
value (in this case 2500 rpm).  So, if the IAC is adjustable (and I don't
know the limits to this adjustment) it might be possible to retract the
plunger (and I'm assuming here) increasing the idle rpm.

Got a response (you can probably see it) from David Cooley in which he
states there is a base idle procedure.  It may be that I simply haven't
"set" the idle correctly.  So I'm gonna go back through my book and check
this out.

Do you have any idea what kinds of scan tools would work with a Saturn?
Thanks.

Rick

> -----Original Message-----
> From:	Shannen Durphey [SMTP:shannen at mcn.net]
> Sent:	Monday, October 26, 1998 9:25 AM
> To:	diy_efi at efi332.eng.ohio-state.edu
> Subject:	Re: Low Idle w/ Saturn tuned port EFI.
> 
> Jemison Richard wrote:
> > 
> > I apologize in advance for bugging you folks with this but I've got a
> > feeling there's something dumb I've done that is precipitating this
> problem.
> > 
> > I originally started having a really low idle (500 rpm or less in gear).
> No
> > increase in revs w/ air on either.  So I checked my codes and the IAC
> was
> > indicated (now I know this meant the IAC was unable to correct the
> problem).
> > At the time I took it to mean the IAC WAS the problem.  I replaced the
> IAC.
> > In the IAC there were instruction stating the plunger should be no more
> than
> > 1" extended.  I double checked this and it was right at 1 inch (it is
> > obviously adjustable.  You screw it in one way or the other - don't
> remember
> > offhand).
> > 
> What is this?  The IAC is adjustable?  I've never seen that, but maybe
> so. 
> Doesn't sound like the good old GM unit. 
> 
> OK, first question.  This idle spped is actually causing problems,
> correct?  Not just annoyingly low?
> 
> Next, do you have access to a scantool?  What are IAC counts?
> 
> 
> Is there any chance you can forward the instructionsfrom the IAC?
> 
> Shannen
> 
> > Anyway, I've since discovered the coils were both weak.  I've replaced
> both.
> > The sucker runs like blue blazes (for a Saturn - OK you Chevy guys!) but
> the
> > idle isn't one bit better!  I tried increasing the idle with the idle
> screw
> > (makes perfect sense to an old carb guy!), nothing.  So I backed the
> screw
> > off completely.  Nothing.  Then I disconnected the IAC with the idle
> screw
> > completely backed off (and this is what's got me thinking).  This thing
> > idles at about 2500 with no IAC and no idle screw setting!  The IAC is
> > actually REDUCING the RPM.  Geez, I can feel you guys out there on the
> floor
> > rolling in uncontrolled laughter.  Go for it!  Just give me the answer!
> > 
> > I'm thinking if I reduce the plunger extension I'll increase my idle.
> Am I
> > anywhere close?  And if I'm not, where should I be looking!?  I've
> changed
> > and checked plugs, changed wires and coils.  I've checked the wiring
> from
> > the coils to the PCM and have checked the PCM (according to the
> excellent
> > ;-^) documentation I have on hand) and it checks OK.
> > 
> > Thank you in advance for your assistance and if you've really enjoyed
> this
> > unbridled level of incompetance I'll try to keep 'em coming! ha!
> > 
> > Rick
> > jemisonr at tce.com