IAC longevity problems

[andy quaas]

The IAC went bad and i drove on it for about a week and then the
actual driver chip on the ECU burnt up and took some traces off the
PCB.  That stopped me dead in my tracks.  It funny because i could
still communicate with the ECU with my laptop, but it wouldn't run the
engine.

At this point ($120 tow job from where i work) i said that i want as
many standard parts as possible, because holley wanted $450 or so for
a new ECU.  So i spent that cash and bought a complete harness and
chip from Howell.  I picked up a 1227730 from a junk yard for $50 and
a new IAC from howell, also.  I plugged it all together (I also had to
get a new map sensor, as the holley works backwards.  So now if i
screw something up, parts are very available and way cheaper.

Andy Q

---MJones <rmjones at cyberhighway.net> wrote:
>
> Andy,
> 
> Thanks for the info.  When your ECU went up in smoke, did it die
completely 
> leaving you stranded, or just the IAC  driver (I hope?)  At this
point I've 
> disconnected the IAC and adjusted the throttle angle to give a
proper warm 
> idle speed.  Since the boat is a warm-weather toy, so far I think I
can 
> live without the IAC.  'Cold' starts don't seem to be a problem. 
Not as 
> quick and smooth as with the IAC but better than the carb at least. 
Since 
> as often as not one of my friends or my wife is at the helm, I want 
> behavior to be as predicatable as possible.  Idle not coming down
from 1500 
> on engine start is not a Good Thing.
> 
> The original IAC and the replacement are both black in color, and
both have 
> a Chrysler part number stamped on them, i.e. go to a Chrysler
dealer, punch 
> in the number and voila they come up with the part.
> 
> What model GM ECU did you use to replace the 4Di?  If you posted this 
> previously, I'm afraid I don't remember:  Who burned your chip, or
is it 
> stock?    I was hoping to avoid that route, which is one reason I
went with 
> the Holley.  I just took up flying again after several years of not,
and so 
> hobby time is limited.
> 
> Mike J.
> andy quaas wrote:
> >I had a 4Di and the IAC went bad (created a hard staring cenario)
> while i was in the backwoods of WI.  According to the holley manual,
> it checked out OK.  About 1 week later, my ECU actually went up in
> smoke.  Guess what went?  The IAC driver.  So i got a GM puter and
> another IAC to use with my 4-bbl holley TBI.  Works great.  Are your
> replacement parts black?  The new IAC that i got is larger in diameter
> and a bit longer than the original one.
> 
> andy Q>
> 
> 
> 

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