And so the time has come to modify the stock AWP engine wiring harness
and integrate the DTA and related sensors into the slimmed down
version. Of course...first things first.....figure out what is
what in the existing VW harness so as to move on to actually modifying
The game plan for all of this is as follows:
Identify everything in the AWP wiring harness for the purpose of
eliminating items that the DTA doesn't need
2. Layout wiring harness
on engine to make sure that all of the components are hooked up that
were determined in step one
3. Remove all AWP wiring
that isn't needed
4. Wire in power
components and gauges
5. Wire in additional
components that the DTA requires
6. Modify the stock wiring by removing components no
longer used and adding fuse panel wiring for DTA and relay board
7. Organize and route all wires
8. Mount DTA and relay
board and route wires to both, adding wires from relay board to DTA
9. Re-bundle all wires and pray to the wiring gods that
you didn't mess anything up and that everything still works
In the end, three separate harnesses should be happily co-existing in
the engine bay: DTA wiring, Power wiring, and Stock wiring.
So...on to the first step...which involves laying out the harness and
stripping off all the covering.
Right, eh.....you guys know what all those connectors, wires, contacts,
relays, and cables are for....right? Well hey...that is what
wiring diagrams are for, silly! ACK! Looks like I have my
work cut out for me on this one....
and so, as a rare surprise, the little cogs in my brain they start a
turning... and I get to thinking....eh....I paid the $100 for the CD
version of the Bentley....why not use it? They have these neato
little pics of a lot of the components and connectors that are in the
But wait...harness is in garage....computer is upstairs....eh...um....
...so while Dan is at work I ferret the harness upstairs and after
laying down some clean towels....out comes Mr. Wiring Harness so that
all of its bits can be properly identified, labeled, and potentially
......and of course the key players in the game: 15 or so pages
for the AWP wiring and 2 pages of DTA schematics....plus the paper
version of the Bentley (which also cost $100...heh).
Okay, so I diligently begin the task of identifying all of the
components of the wiring harness.......marking their designations from
the wiring diagram onto a piece of masking tape and then taping that to
....enter Dan...home from work...."Why Kirsten....you don't really need
that big 'ol bulky hunk o' Mass Air Flow Sensor upstairs, now do you?"
"Guess not Dan....have at it....."
"Okay, I will just disconnect it from the harness and then you can put
that them there label onto the wires....."
"K".......5 minutes pass......Dan is still trying to get the Mass Air
Flow Sensor off of the harness......so I pipe up....."let me have a go
Dan begrudgingly hands me the MAF and sits back......5 minutes
pass......and then I spy a little tab hidden down in the crevice of the
connector...."That has to be it......" says I.
"Nah" says Dan who has taken the part back out of my hands and is
tinkering with it.
"Yeah" I say taking the MAF back into my hands to further inspect the
part (Dan gets up and grabs my camera.....)
We will just see about
Despite what Dan says...I know that the tab I have just found is the
golden key to unlocking this puzzle........it just doesn't want to
....won't come out, aye? Well then....enough Miss Nice
Girl! Now you will feel the wrath of my flathead!
.....I know it is going to cave soon.........
.........and VICTORY is mine, mine, mine!!!!!!!!!!!!!!!!
"see Dan....I TOLD you it was that little tab...." Told you, told
you, told you!!!!!! HA!!!
My victories are so few and far
between that every little one is like winning the lottery for me......
........and now I sit downstairs while Dan is sleeping away, humbled I
am sure! (LOL!)......
and awaiting my return? A now MAF-free wiring harness, with only
a small portion of the bits identified......
But soon many victories will be mine....oh yes, they will!
The irony of this all is that the MAF doesn't even live on the part of
the wiring harness that ended up getting used.....live and learn I
And so I return to the task at hand: sorting through the harness
and identifying the remaining bits (Dan happens to catch this on camera
as well.......he is a bit camera happy since discovering that I will
let him use it)...First though, it turns out that the actual harness is
composed of three sections..... As it turns out, the only piece
of this that is needed is the main engine one, but it was not until
AFTER I finished unwrapping the other pieces that this was
Above are the two other pieces of the harness that won't be used.
To the left is the main piece which IS being used.
So with victories in the distant past (all of one day at this
point....) I begin slaving away once more...
No Dan, I DON'T appreciate you
taking my picture...thank you very much!
you have never stripped a factory wrapped wiring harness, let me
tell ya...it is incredibly time consuming at best. There are a
multitude of layers each one consisting of a veritable smorgasbord of
wire bundling material showcased in an infinite number of strips...each
with a length not exceeding the girth of said wiring harness. After
many, many hours of tedious unwrapping, I had two very naked wiring
The one being used is on the right...
In sorting through everything though, I came across a section of
damaged wire....unfortunately, the damage was on the section of harness
being used.....and despite the outer covering not being damaged,
somehow the interior was. And it wasn't just some of the wires
either....it was pretty much a large chunk of them....right in the
middle of everything.
left-overs....carcasses of wiring covers abound and many a piece of
electrical tape covered the floor in Dan's kitchen....fortunately, I
cleverly picked it all up before he got home from work, so he was none
So moving on.........
With the harness stripped of all it's clothing, and all the bits
identified......it is finally on to step number two, which is to
install this puppy onto the engine so that I can confirm what is not
needed before removing the potentially extraneous wires.
First off? The intake manifold has to move into its home
temporarily for the purpose of wiring placement.....(not so pretty, is
Now with the intake manifold on...time to layout the harness and see
what goes where...
Okay....first up.....coil packs and injectors....
Towards the bottom of the
picture, you can see the Intake Air Temp Sensor (G42)
Above you can see the Camshaft Position Sensor (G40)
This is the Oil Pressure Switch (F1) on top of the oil filter
housing...this will be removed since I will be using the '79 setup.
....and the Engine Speed Sensor (G28)
.....and the Coolant Temp Sensor (G2 and G62 both are housed in the
same connector body)
The Speedometer Vehicle Speed
Sensor (G22) is what is in that silver heat shield pouch. It is
slated for removal.
The connector on the left is the
Charge Air Pressure Sensor (G31) which will be removed.
The connector on the right is for the Power Accelerator Actuation
(G186, G187, G188).
...and of course, last but not
least....the stock wiring components in the engine bay which will be
Okay...with everything identified and connected...here is what the
final layout looked like:
So...let the removing begin! YAY! Finally on to step
3. First up? The drive by wire stuff. There are six
wires for the power accelerator actuation: Two wires go to Angle
sensor 1, two wires go to Angle sensor 2, and two wires go to the
throttle drive. After cutting off the connector body which was
located on the throttle body side of the intake manifold, I pulled each
of the wires out of the first section of harness (which also houses the
camshaft position sensor, intake air temp sensor, and injector
wiring). I took the drive by wire stuff out because I will be
using cable actuated throttle instead.
After that, I pulled the wires through the rest of the harness...and
finally had them all layed out. You can see I taped the ends to
make it easier to pull them through the wiring bundles I made with
and now all bundled up ready for the final cut:
Here are those damaged wires again....the majority of the wires were in
need of a soldering fix....for now though, I just used electrical tape
on the damaged sections as a way of identifying which wire were damaged.
Now to work on getting the Speedometer Vehicle Speed Sensor (G22) and
Oil Pressure Switch (F1) out:
You can see in the picture above I have also cut off one of the knock
And finally, the wires for the
Speedometer Vehicle Speed Sensor and Oil Pressure Switch are out and
bundled together at the T14a connector.
Since the DTA doesn't have knock sensing capabilities, both knock
sensors were taken out of the harness. Each knock sensor has two
and a shielding wire.
The shielding wires appeared out of nowhere (or so it seemed).
Now to cut some wire at the connector.....First up are the wires for
the speedometer vehicle speed sensor and oil pressure switch.
Then I cut the ground wire which was connected to the T14a
Now to remove the Charge Air Pressure Sensor (G31) since I will be
using a separate MAP sensor instead. The green/lilac wire splices
into two individual wires mid-harness. One is for the camshaft
position sensor and the other is for the charge air pressure
sensor. I cut the CAPS wire at the splice and then wrapped the
end with electrical tape.
And finally, the Recirculating valve for the turbocharger (N249) was
removed since the bypass valve will be getting the vacuum signal
directly from the intake manifold. The yellow/black wire splices
into two wires mid-harness
as well, with one wire going to the N205 valve and the other going to
the recirculating valve. As before, I cut the wire by the splice
and wrapped the end in electrical tape.
So here is what is left at the ECU connector end of the wiring harness:
Knock sensor wiring all bundled up...
...Power accelerator actuation ready to be cut from the connector
...with the remaining pieces to be bundled together with the knock
Finally, everything bundled together.....
The camshaft position sensor and engine speed sensor share a shielding
wire at the ECU connector end....this became quite a frustration at
So here are all the connectors/components that I removed:
Power accelerator actuation connector....
Vehicle speed sensor and heat shield....
....and the recirculating valve connector
.....and some of the wires........
I also did a preliminary wiring in of the TPS. All that really
entailed was selecting the wires and putting 'em into the connector
body....I left it at that for now:
....and then Dan drilled some holes in Shocky's rain tray (I couldn't
bring myself to do hurt Shocky like that) and I mounted the MAP sensor:
Finally, I harvested a bunch of 20 gauge wire from this guy...for
things to come: