4500rpm cutout and boost in neutral. Codes 2223 and 2342
PeterBergin at aol.com
PeterBergin at aol.com
Wed Mar 28 21:24:05 PDT 2012
Looks like you covered all the bases. I would unplug the MAF and see if
any thing changes. And you have sparks around the distributor. I would
check those two carefully. When my MAF failed it acted similar with no codes
or check engine light (If you have one),
Pete
91 Avant sold last summer
02 S6
In a message dated 3/28/2012 8:02:00 P.M. Central Daylight Time,
audisport44 at yahoo.com writes:
Hello everyone,
I haven't been part of the list for some time now but I'd like to revisit
an issue I've had with my 200. I didn't have time to mess with the car due
to other priorities but I'd like to see if I can figure out the problem this
time around.
The car is a sedan with almost 200k on the odometer.
My main concern is that I cannot rev the engine past about 4500 rpm. It
gets stuck at that point and the tach needle bounces as if it's hitting a rev
limiter. While this happens you can hear the car misfiring severely. The
car acts this way wether it is in neutral or under load. Also easing onto
the gas is the only way you can even get it up to 4500. If you try to give it
too much it'll choke right away and start misfiring. The weirdest part is
that it actually builds boost in neutral. I know I've said this before and
nobody on here believed me so I'm including a video of the phenomenon. The
digital gauge in the car says it's building boost and so is the mechanical
one I temporarily hooked up(this is a verified good gauge that I used in
my B5 S4). The video shows vacuum at idle and boost when it hits that
cutoff. Also you can see the tach and where it stops when you rev the car. It
will never go past that no matter what you do and what the
condition is.
Here's a list of things I've done to try and track this down:
-Pressure test (all good and held at least 20psi from what I recall)
-Replaced ecu with another good unit
-I did a fresh headgasket, valve job and timing belt (timing is on 100%),
I can attest there is nothing physically wrong with the engine
-Cams were checked for alignment at tdc and the Os line up as they should
-Replaced O2 sensor with original bosch unit
-Replaced altitude sensor with good unit
-New fuel filter
-New line from bypass valve to intake manifold
-Took bypass valve, spark plugs and wastegate frequency valve from my B5
S4. None of them made a difference
-Checked wastegate and it moved freely, not stuck. The diaphragm is also
free of holes
-The car has no cats, they were gutted by previous owner
-I also disconnected the catback just to be sure so I can say the car
isn't choking from clogged exhaust
-Took apart throttle position sensor, all contacts were good. I also
measured it and it checked out
-Tested hall sensor and it checked out
-Tested RPM sensor and also replaced it with known good unit, which didn't
help
-Checked all teeth and timing reference sensors on flywheel, nothing was
amiss
-I believe I replaced the timing sensor too, which of course didn't make a
difference either
-Maf was tested by someone and was told it checked out
-Checked pretty much every connector under the hood to make sure it had
the right values and no faulty wiring
-Checked wiring leading to ecu, relays and fuse panel as best as I could.
Didn't see anything odd
-Did output test, everything was normal. I don't think the carbon canister
solenoid(or whatever it's called) was getting a signal though
-It makes no difference if the car is hot or cold. It always runs the
same, sometimes it will start to idle very rough too and not really want to
move at all
-Cleaned idle stabilizer valve
-Tested air temp sensor, which was fine
-All fuses are there and not broken
-Distributor has metal gear, no teeth cracked or broken on it or the
camshaft
-I noticed some arcing from the distributor area one night while the car
was idling, if I remember correctly it was around the hall sender
-The temperature gauge isn't always receiving a signal
My brother was in front of me driving the car one night and it just
wouldn't go anywhere(worse than before), then he said all of a sudden(and I saw
this), the car took off as if something unclogged and it just pulled to
80mph. After that it started bucking again and never got "un-stuck" again.
While I was behind him I saw a few little bright red pieces comming out the
exhaust. They looked a lot like bright burning ash.
When the car hits that 4.5k limit, you can hear a clicking in the ecu,
like a relay. And the wastegate frequency valve will frantically start
clicking away too once you've let the gas go. I've heard it under the hood quite a
few times.
Anyways, I'm not sure what else I can say about all this....I'm sure there
are things I did which I forget. If I recall something else I will post it
on here. Or if you have any questions about a particular part you didn't
see checked, let me know.
Do our cars have this issue at all? This is something about a 4k cutoff
due to faulty brake light on intended acceleration:
http://www.intendedacceleration.com/tip_2.html
And lastly, here is the video I recorded. It shows exactly what my car is
doing:
http://www.youtube.com/watch?v=STydKk6Ja28
Thanks and sorry about the long e-mail. I just tried to include everything
before I'm asked what I've done to diagnose this :)
Dan
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