From HAREST AT allenbrook.iix.com Wed Dec  9 10:16:25 1998
Date: Mon, 27 Apr 1998 17:18:33 -0400
From: HAREST AT allenbrook.iix.com
To: quattro AT coimbra.ans.net
Subject: 4kq turbo conversions - MC code motor wiring (& questions)

Afternoon Guys and Gals!

With all the topics flying around recently, I thought I'd see if I
could start a feel good thread.  (That is, I'll feel better when my
turbo conversion is finished...)  The only spider bites here were a
result of the critters who reside in my garage, and have expressed
their approval of my car with exotic web designs ;-)

Hopefully the formatting doesn't get totally trashed getting to
everybody.  I avoided the use of tabs to help.  Here goes...

The patient is an high mileage 84 4kq, who's been patiently waiting
for me to get back around to her turbo conversion.  I spent a lazy
weekend in the garage with the ole girl to see how much progress I
could make.  Removed the battery tray, most of the interior including
the dash, the damaged heater box, the seats, the carpet and soggy :-(
padding, and the old brain wiring.  After a little cleanup, I ran the
new battery feed line to the trunk, ran the heated seat wiring
harness, ran the power window harness from a 87 4kq, and muddled over
the 4kq and 5ktq wiring diagrams.

I have the complete wiring setups from an 86 5kt (auto) and from an 86
5ktq (5spd).  The 5kt harness is in better condition, and was the one
I chose to reinstall.  The harness consists of the various engine bay
connections, the brain and its connector, the idle stabilizer brain,
and kostal connector T14b from the wiring diagrams.

After tracing through the Book of Robert, Chapter 97, verses 324
through 328 I am left with a few questions.  I'm hoping that some of
those who have gone before, or are just gone ;-) can give a second
opinion confirming my thoughts.  Orin, Scott, Martin, Dave, Ben,
Steve, others??

The easiest part of the wiring is the engine bay.  If there's a
connector, find it a good home.  The only exception is one of the two
green wires going to Terminal 1 on the coil pack.  One of these is no
longer used...

The next part is the brain.  Not much to it's wiring, only it's
programming.  QLCC ;-) The one question I have there is with Pin 34
(97.324 Trace 47).  Bentley lists it as a Brown/Green wire connecting
to ground.  On my harness (5kt auto), pin 34 is Brown/ Gray and cut
(from the factory probably).  Thoughts on this are that it was cut in
the automatics to limit boost some, and that I can reconnect this to
Ground.  I have yet to look at my 5ktq harness to confirm.  Thoughts?

Moving on to kostal connector T14b we have more fun...
Pin   Color             Trace    What/Where/Why
1     Green             79         Coil Pack to Auto Check, Main Control
2     BLANK
3     Green/Violet      45         Feeds power to misc. items
4     Blue/White        54         Cold Start ground
5     Yellow/Blue       55         Signal to Boost Gauge in Computer Board Display
6     Brown/Blue        50?        Ground connection
7     Green/Yellow      82         To AC stuff
8     Violet/Black      50         Signal to tachometer in Computer Board Display
9     Red/White         84         To AC stuff
10    Green/Brown       86         Decel cut-off Ground (?) to Computer Board Display
11    Yellow            47         Fuse box connection (ILa) to Fuel Pump Relay
12    Red/Yellow        51         Power from brake light switch
13    Blue/Black        56	   Ground to Computer Board Display, Oxygen Sensor Related?
14    Brown/Green       49         Fuse box connection (BS) to Fuel Pump Relay

Now, keeping in mind the AC has been removed from this vehicle, so:

Pin    Do/Don't Need    (my perceived function)
    Probably Yes/Probably No

1       Probably No       (Signal to Autocheck unit that vehicle is running)
3       Probably No       (Supplies power to several items, in remaining 4kq
harness)
4       Do Need           (Cold Start Valve Ground)
5       Probably No       (Signal to electronic Boost Gauge.  Use a manual
                           gauge instead)
6*      Do Need	          (* This may be an undocumented connection.  I
                           searched the diagrams and didn't find it illustrated.  But
                           Kostal T14b, Pin 2, BR/BL has continuity with Brain, Pin 6, BR/BL,
                           Trace 50 * )
7       Don't Need        (To AC stuff, and ta da... no AC.  Bear this in
                           mind for other vehicles)
8       Probably No       (Tach signal from Brain.  The 4kq gets its tach
                           signal from the coil, pin 1
                           97.55 Traces 43-46.  Existing 4kq wiring
                           will be connected to the 5ktq
                           coil pack instead of the other end of
                           Kostal T14b, Pin 1.)
9       Don't Need        (To AC stuff, and ta da... no AC.  Bear this in
                           mind for other vehicles)
10      Don't Need        (To/From the Computer Board Display)
11      Do Need           (From Fuse Box/Fuel Pump Relay to Knock Sensor
                           Light.  This should be
                           the light used to "dump" the computer
                           codes.  Connect to your light of choice)
12      Probably Yes      (Power from brake light switch.  Not sure what this
                           is being used for exactly,
                           but it is easy enough to tap this
                           connection in the 4kq...)
13**    Don't Need        (Some sort of ground feed to the Computer Board
                           Display.  ** T2a Trace 57
                           connects to T2a Trace 59 ** )
14      Do Need           (From Fuse Box/Fuel Pump Relay)

The last(?) piece of the Brain Harness puzzle is the Idle Stabilizer.
While it is good to keep in mind what it is doing, it only contain 3
unused or unnecessary wires, or 1 unnecessary wire if you're keeping
AC intact.  And all of those wiring can be terminated at T14b.

Idle Stabilizer Pin     Kostal T14b Pin     Trace      Use
2/k                       7                  82          To AC
stuff
6/KA                      9                  84          To AC
stuff
15/SAS                   10                  86          To Computer
Board Display

So to wrap this up, I'm hoping that some others can offer up reasons
and logic to change my Probably Yes' and Probably No's to Do's or
Don'ts.  And for people to spot any of my Do's or Don'ts that are
wrong.  The tach signal, knock sensor light and power from the brake
light switch are my primary concerns.  The rest I'm comfortable with.

The other piece to the turbo conversion is the wiring for the
after-run stuff, turbo cooling pump and injector fan.  I think it is
easier to do some custom wiring adaptations here, than deal with the
whole left side 5ktq harness.  In the future I'll probably expand on
this, including more on the aux. cooling functions, and more on the
stock 4kq left side engine bay wiring harness that must still be used.

Hope you enjoyed the reading...
-Stott