of VAG-COM and 200q20v's (part one)
Brett Dikeman
quattro at brettd.dsl.speakeasy.net
Sat Feb 17 22:55:43 EST 2001
At 3:33 PM +1300 2/18/01, Dave Eaton wrote:
>how long did you let the car idle after you ran it? if over 5 minutes have
>elapsed, you need to re-run the car - the manual states "if the engine runs
>at idle speed for a longer period, the specification may be exceeded without
>an actual fault existing".
Hmm. Didn't notice this...are you sure this isn't something specific
to the UrQ/RR? I'll check in the Bently more closely though.
Basically, I let the car warm up to the point where it hit(and
stayed) within the range recommended for channel 1, motor
temperature. I don't think it ever topped 200.
>also, the actual value for display field 7 is amended in later 20vt manuals
>(aby, aan) to be from 41-61. as the isv hasn't changed, you are ok anyway.
okay, sounds good.
>if required, the isv should be checked 2 ways - static resistance across the
>two terminals, and using the output tests of with the isv unbolted, and
>checking to see whether there is any "stickiness" to the movement of the
>rotary slide valve. don't touch the slide valve - if looking a little
>sticky or slow, you can clean it with carb cleaner which may help.
the valve is completely clean; I actually cleaned it last night for
the hell of it. There was considerable dirt/whatever inside the
connector and on the terminals, and a spot of oil goup inside the
vane movement.
I did an output test with it back on the car, and the valve
cleanly/totally opened, then snapped/bounced shut with a little "ker
poing"; movement when pushed around with qtip was smooth/fluid and
even, no sticky spots.
Idle still doesn't seem quite right; still occasionally hiccups and
drops, labors a little, then recovers. Sitting at idle at a traffic
light, it goes smooth-rough-smooth-rough slightly.
At 2800 rpms or so in 3rd, engine speed will fluctuate back and
forth, maybe 2 times a second; I can watch the tach wobble slightly.
This is very repeatable, as it's the speed I do through most of my
daily commute.
Couple of people have suggested a faulty O2 sensor, but it's not that
old, and none of the ECU values seem to indicate a problem with the
sensor.
I drove the car home and letting it idle for several minutes while I
played with VAG-COM; a little while later after pulling the valve and
cleaning it out, I started up the car again and recorded a few
values, they should be tab delimited and CR/LF'd at the end.
1 2 3 4 5 6 7 8 9 10
0 0 0 130 88 131 48 132 116 0
136 28 88 124 82 131 48 129 116 40
171 23 80-90 124 80 130 48 129 116 36
189 23 75-83 126 78 130 48 129 119 36
193 22 76-83 124 78 130 48 128 119 36
comments(for each line)
stopped, off for about hour, engine not running(many values don't
show up until engine is actually running)
valve cleaned, car starting to warm up
warming up more
warmed up(in range)
same
Does anyone have docs or notes on what the single value readings are?
Note, these are -not- the "channels" the bently refers to, these are
internal values from the A/D converter according to Uwe. The Bently
is referring to Block 000 channel readings...
He and I tossed around the idea of building tables for various
controllers that would let VAG-COM interpret them(same for the block
000 values.) It's a pretty big effort, because "practically every
controller's registers are different."
I figure I can probably figure out a lot of single values on my car,
simply by looking at a block and unplugging a sensor, moving the
throttle, etc, to see if it . Granted, it will take forever, but
when VAG-COM supports logging(Uwe says "soon!") this could allow for
a complete black-box style log of everything during a test drive.
Call me nutty and slap me stupid, but I think that will cause a
literal renessance in terms of the time it takes to troubleshoot Audi
engine problems; 6 months from now, we could all be posting charts of
what we're recording along with "it's surging slightly at 2800 rpms
or so" and someone says, "hey, look at the O2 sensor line, it's doing
xyz, there's your problem right there"...I think this will be
especially useful for things like boost problems.
--
----
Brett Dikeman Systems Engineer
ProAct Technologies Corporation 914-872-8043
(formerly CFN[formerly iClick, Inc]) 914-872-8100(fax)
120 Bloomingdale Rd. http://www.proacttechnologies.com
White Plains, NY 10605
PGP Fingerprint: 06C2 5D5B D2B4 7626 BB24 2BBC 9E4A C8B3
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