Sun Jan 16 11:05:02 2005
From: Flash 

Here's a guy from Hooterville, WI - Jim's neighborhood who tweaked his 300D
2.5 and has gotten rave reviews (he raves) about the performance.  These may
be understandable tweaks, and something John with his 2.5 and others here
with 2.5 may want to try?  Let us know what happens, if/when, john,
others...
DanG ChicagoArea
====================
I've decided to go into great detail of what I did to the 2.5.  The white
2.5 had a blown head gasket when I got the car.  It contaminated a number of
vacuum items, which is why I started bypassing stuff.

1) Overboost protection canister.  Small one on the driver's side firewall.
Had soot in it, and prevented the ALDA from sensing pressure.  Bypassed.  I
don't think that I've had ONE of these work correctly on any turbo.  They
all get sooted up eventually.

2) EGR.  Also full of soot.  I have a good replacement, but haven't gotten
around to replacing it.  An EGR on a diesel is a dumb idea anyways because
feeding soot back into the intake is not good for it.  Bypass is easy.  Keep
the electrical connections intact to the vacuum pod.  The signal to open and
close will be there, and the computer will be happy.  Disconnecting the
vacuum lines and bypassing is all that needs to be done.

3) Turbo wastegate vacuum pod.  The wastegate has a vacuum failsafe that is
normally open with zero vacuum.  Bypass is to connect the wastegate vacuum
(which is the electrical/vacuum pod closest to the passenger side headlight,
low in the inner front fender), and hook it directly to the main vacuum
system.  My wastegate vacuum pod leaks, and I need to replace it.  Bypassing
is only temporary, as that particular failsafe is not good to ignore for too
long.  The key to preserving the computer happiness is not disconnecting the
electrical harness to the vacuum pod.

4)  Secondary turbo fault sensor.  If something is very flaked up with the
computer or sensors, the secondary sensor which is mounted by the battery,
opens to kill boost pressure to the ALDA.  Bypass is easy for troubleshootin
g.  The only reason why you would want to bypass this for any reason is to
find other faults.

My point is that the highly sophisticated computer controlled turbo system
can be made very simple.  Call it emergency road repair 101.  If you have a
full time vacuum direct connect to the turbo wastegate, you'll have turbo.
If you have a single pressure line from the intake manifold to the ALDA,
you'll have appropriate fuel enrichment.  Leaving electrical items attached
to the vacuum pods keeps the computer happy and compliant.