[Syty] Broke & Stumped!

[DOlivares]

Who watches The Watcher?  

Who advises The Guru?

Who assists The Good Samaritan?

I think we're about to find out pretty soon-- at least until I can get my Lapdog running again (and one of the diagnostic programs to troubleshoot my li'l pony):

Meanwhile, I NEED HELP!  With my laptop in pieces all over the bench, I can't run DIACOM or DATALINK to give me clues about the usual suspects:

Clean-livin' doesn't always pay off if my holidaze so far are any indication.  I spent Christmas Eve on a carlift taking apart my right-front axle-- again!-- after being assured by our local "Gear-Guru" (who fully rebuilt that differential less than 6 months before I started hearing that same CLUNKING on left turns again) that all I needed was a new cir-clip (GM #14041989) to keep the axle from popping-out of the side-gear in the differential.  HAH!  More bad advice and I ended up taking a cab home....  More about that Horror Show in a later mailing.

Meanwhile, we got our first technical freeze down here in what was becoming tropical San Antone on Nov. 17th and our first hard-freeze, appropriately, on Dec. 7th, and somewhere in between those times ol' Syclone #773 began throwing fits during start-up and for the first 5 or 6 minutes until the water jacket hits and stays at 180° or so.  I'm stumped for the first time in a decade or more!  Here's what happens:

Since the new Walbro fuel-pump went in a few months ago, cranking times are way down... engine catches pretty quick, but now it won't stay lit and "choke" with the new IAC, which went in along with a new TPS and remote-adjustable FPR about a month before the new Walbro.  Now, I have to feather the pedal once the ignition gets going and hold the throttle open a bit while the IAC hunts for about a dozen cycles making the tach swing about 1200 rpm back and forth until we hit the "sweet spot" and the engine takes off smoothly and the IAC-hunting stops, at least for a while.  Now, it's safe to put her in gear and drive away as long as I keep a little positive bias in the pedal for the next few minutes every time I have to slow down to an idle or coast speed.  

THIS PROBLEM IS WICKEDLY WORSE ON COLD DAYS, where ambient air is in the 40s or below, which thankfully is rare.  (Ain't this global-warming great!)  However, on a couple of occasions when I did have to drive in the 30s-- and even after reaching full-warm-up temperature-- the engine starts cutting out seriously as the SES light comes on!  Now, we're talking some MAJOR pumping of the pedal to keep things lit and if I can get on a clear piece of road and cruise a spell at 35 mph or better the problem goes away completely, until I shutdown and the engine gets cold again.  I barely even recognize that SES light... hardly ever see it.  Driving on warmer days never sees a recurrence of that mid-period cutting-out, and idle is smooth as is the rest of drivability.  Warm start-ups see a few moments of that IAC-hunting, but the rpm-sweeps are only on the order of 500rpm and the whole anomaly goes away in about 30 seconds.  I've NEVER encountered anything like this in my many years of wrenching!  Now, it's time for some wretching!!  All that ever gets logged in the way of a trouble-code is 44... not too helpful!

Naturally, I replaced the O2 sensor-- no improvement at all!  Everything described above instinctually told me this was a weird thermal transient in the injector-drive circuits or else the MAT, CTS or MAP I replaced (for the hell of it) 3 years ago needed to be switched again.  So I did... one at a time to see if I could fault-locate the culprit that way.  No dice!  I'm running out of hardware to replace!  I've even tried setting that 10-to-1 Chip to different settings, but the same nasty behavior persists-- the engine's as well as my own!

WHO CAN TELL ME WHAT MY PROBLEM(S) IS?  Be nice, now....

Dennis O.
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