I have noticed the same thing Curt, I'm not going to guess what it is or
isn't, but I can say it doesn't do it anymore (9000 miles).
__________________________________
Matt -- Mechanicsville, VA Y2K-HEMI
`00 Sport Plus 4.7L 5spd. 9 1/4 3.92 LSD
RC 2x4 Homemade intake & K&N open element,
Traction Bars, Spring clamps
BEST 1/4 14.80 @ 90.97 MPH
ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ
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-----Original Message-----
From: Curt Coulter [mailto:curt@cjnetworking.com]
Sent: Monday, March 27, 2000 10:53 PM
To: dakota-truck@buffnet.net
Subject: DML: RE: 4.7L Idle Oscillation
I don't know about all this. When I first got the truck it was very
noticable, now it doesn't do it AT ALL. I have specifically watched for it
and it's not doing it. I chalked it up to the computer learning process.
-Curt
-----Original Message-----
From: owner-dakota-truck@buffnet.net
[mailto:owner-dakota-truck@buffnet.net]On Behalf Of Robert Parenti
Sent: Monday, March 27, 2000 10:31 PM
To: Dakota List Posting
Subject: DML: 4.7L Idle Oscillation
I'm a new list member and saw this discussion a couple of weeks ago. Sorry
if it's already been covered. I just took delivery of my 2000 sport reg cab
4.7L 5 speed manual 3.92 LSD full anti-lock, so I am able to see the problem
first hand. It's mild, but real. I think my new build benefits from the
fixes mentioned below. Got the following from a close relative who works at
Chrysler Truck Division. Interesting reading:
Yep, idle oscillation has been a problem on the 4.7L. They initially tried
to blame our transmission (or rather a dragging torque converter clutch)
for variably loading the engine down. We proved it wasn't and never heard
another word, probably because they realized the manual trans did it too.
A friend that works for me here is actually one of the smartest engine guys
around, especially with anything Chrysler. He's buddies with the engine
calibrators at Jeep/Truck and helps them sometimes. Apparently all of the
magnum engines are prone to idle instability, due mainly to the huge volume
of the intake manifold. The throttle body is so far from the cylinders,
that any change to the AIS (Airflow Idle Stepper) motor takes a while to
affect air flow to the cyclinders. This type of lag will cause any control
system to go unstable if you're attempting to control it quickly. There's
not a whole lot that can be done for this one, which can suck because it
can actually cause stalling if it undershoots enough. They've changed some
engine calibrations that should help, they are more agressive with the
'spark scatter' to try to control idle speed that way, also increased
target idle while coasting down to try to avoid the undershoot/stalls.
Rob
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