[s-cars] 1.8t Coil Pack Conversion - Instructions

[Dave Forgie]

1.8t Coil Pack Conversion for the Audi AAN Inline turbo 20 valve 5
cylinder engine

This conversion is intended as an alternative to the original equipment
(OE) ignition system that uses two 3-channel power output stages (POSs)
and five individual coils each with a replaceable sparkplug connector.
The 1.8 t coil pack conversion works but there are no guarantees about
improved performance or freedom from failures.  The 1.8t coil packs have
built-in POS units as well as coils and plug connectors.  At the time of
writing this, these 06B 905 115L coil packs were about $30 each.  In
comparison, the OE POSs were about $150 each (you need two) and the OE
coils were about $115 each (you need five).  So even if the 115L coil
packs do fail every once and awhile, they are far less expensive than
the original ignition system.

Before you start the installation you should have read the following:

The parts shopping list:

 http://www.audifans.com/pipermail/s-car-list/2005-September/044174.html

The Pin-outs:

 http://www.audifans.com/pipermail/s-car-list/2005-September/044175.html

Once you have the parts and understand the pin-outs, you can proceed:

BEFORE YOU GO OUT TO THE CAR:

1. Load the 20 female pins with pigtail wires into the 5, four-pin coil
pack connectors.  If you purchased the pins as the two-pin, yellow-wired
pigtails, snip the wires in the middle before you load the pins.  For
me, the pins did not want to slip into the connectors as easily as I
would have wanted.  I had to push them in with a metal tool (from the
rear) so the front of the pins were in the correct position. Add the red
silicon wire sealant grommets from the rear.  Once you are done, try a
connector in a 115L coil pack.  Try removing the connector (press down
on the square bail and pull back).

2.  Regenderize the Jetta tail light connectors as per the parts list.
Load four male pins (and wires)  into one and two pins in the other (in
Positions 3 and 4). Add the red silicon wire sealant grommets from the
rear.

3.  Cut the wires on the two, 3-pin Jetta O2 sensor connectors so there
is 12" to 14" of wire.

4.  Trim and modify the 115L coil packs.. You need to end up with a
ribless band of silicon rubber about 6 to 8 mm high under the hard
plastic part of the coil pack tube.  The rubber over the ridge on that
hard plastic part of the coil pack tube needs to be removed as does the
ridge itself (I used a Dremel and great care to ONLY take the ridge
away).  The bottom half of the square(ish) plastic "box" needs to be
removed.  Find a F5DP0R sparkplug.  Practise pushing the 115L down onto
the spark plug.  It should go down far enough so the coil pack clips
over the hex part of the spark plug.


OUT AT THE CAR:

1.  Remove the OE coil pack. Remove and save the four 5 mm hex socket
bolts.  Disconnect the coil pack from the two POS units and the two
power connectors on the firewall and the single ground wire to the
passenger side rear of the cam cover.  Remove the coil pack gently and
store in a safe place.  If you follow these instructions, if need be you
can go back to the OE system within 20 minutes if something seriously
goes wrong with the coil pack conversion.

2.  Check your spark plug torque.  22 lb-ft.  Tighten only.  Never back
off and re-tighten.  Do all five. (Two of mine were loose-ish).

3.  Grab one of the trimmed 115L coil packs and pull the rubber ring you
left down off the coil pack.  Now try installing the coil pack down onto
the spark plug. It should go down far enough that the top of the coil
pack is about 1/4" (6 mm) below the top of the cam cover.  You should
hear the coil pack "snap" (click) onto the spark plug. Try this on
another spark plug.  Measure the distance down to from the cam cover.
Remove the trial 115L and replace the rubber ring you removed a few
minutes ago. Try installing the coil pack again.  It should go down the
same as before but you will not hear the click/snap because the rubber
ring prevents the sound from leaving.

4. Coil pack orientation is a variable but you need to decide before you
start the wiring.  IF you do not use the snap-on caps to corral the
wires coming out of the connectors, you can point the coil packs to the
7 o'clock position.  However, if you do use the snap-on caps (which I
recommend for neatness), then I found that the best orientation was as
follows: No.1 (at the front) - 7 o'clock. No. 2, 3 and 4 - 10 o'clock
and No.5 (at the rear of the engine) - 5 o'clock.  Even with this, the a
corner of the snap-on cap and the 115L itself need to be slightly
trimmed on No. 1 and No. 5 to get a little clearance.

5.  Once you have decided on the coil pack orientation, then you can
start the wiring process.  I left the coil packs in their respective
holes, oriented as desired but NOT pushed all the way down (yet).  This
makes connecting the coil pack connectors easier.

6.  You need to be methodical in doing the wiring, and remember to put
the heat shrink over the wire at the correct time.  Connections can be
crimped or soldered. IF you are crimping, I recommend a racheting
crimper (more power and more precision) AND using butt connectors that
have built in heat sealant (which you activate like when you shrink heat
shrink).  The objective is a good mechanical connection with no chance
of moisture problems.

7.  I started with wiring all of the No. 1 pins on the coil packs to the
switched power connectors (the Jetta 3-pin O2 sensor connectors
installed into the metal connector rack on the firewall).  I started at
the front with Cylinder No.1 and moved towards the rear, planning how I
was going to route the wires, as I went.  Note: Because my No. 1 coil
pack was pointed to 7 o'clock and I wanted to run the wires on the
intake side of the cam cover well, those wires had to loop a bit around
to get past coil pack No.2.  Likewise, for No. 5, those wires had to
loop around coil pack 4 (on the coil pack 3 side) and actually join the
"harness" before coil pack No. 4 wires.  Because I didn't think I could
get a solder connection to the O2 sensor wires, I used crimped butt
connectors.  I think only cylinders 1 and 2 required extension wires.
No. 3, 4 and 5 where direct connections between the pin pig-tail wires
and the O2 sensor wires.

NOTE: Since doing this, I am wondering why each cylinder needs its own
power wire.  Another way to go MIGHT (YMMV) BE to run a single 12 or 14
gauge feeder wire from one fire wall connection and then "tee" into that
wire with the five Pin. No. 1 coil pack wires.  This would result in
fewer wires and less congestion in the wiring harness.

8.  Then I did the Pin. No. 3 connections to the ECU wires.  This is the
one you really have to make sure that you don't make a mistake on.
Study the Pin-out text again.  You need to connect Pin. No. 3 of Coil
Pack No. 1 to the green wire wire position (Pin 4) of the four pin
regenderized Jetta taillight connector (stuck into the POS No. 1 (N122)
connector with its boot pulled back so you can see the ECU wire colours
and positions).  Watch your wire routing again. Extend wires as
required.  Pin 3 Coil Pack 2 goes to the Violet Purple position (Pin 3
on the 4 pin Jetta taillight connector).  Pin 3 Coil Pack 3 goes to the
Black Grey position (Pin 1 on the 4 pin Jetta taillight connector).  Pin
3 Coil Pack 4 goes to the Black Yellow position (Pin 4 on the other
Jetta taillight connector (the one with only two pins) stuck into the
POS No. 2 (N127) connector with its boot pulled back to expose the ECU
wires).  Pin 3 Coil Pack 5 goes to the Black White position on the
second Jetta taillight connector (Pin 3 of 4).

9.  For the coil pack POS ground, I used a single wire and T'd in the
wires from Pin. 2 of the coil pack using solder and heat shrink.  I did
this by routing the a 14 gauge brown wire from around the firewall,
along the intake side of the cam cover well.  Coil Pack No. 1 was a
straight "butt" type connection.  For the other four connections, I
routed the Pin 2 Coil Pack wire to where I thought I wanted the "T"
connection to occur.  Then I very carefully stripped off about 1/2" (13
mm) of the 14 gauge wire cover.  I cut the yellow wire to the
appropriate lenght and stripped off about 5/8" of insulation. Then I
wrapped the exposed yellow wires around the open 14 gauge wire section
and soldered them together.  Then I cut a section of heat shrink about
1.5" long and slipped it over the 14 gauge wire from the firewall end
and then over the connection I just made. The "T" becomes more of a "Y"
but it works.  Shrink the tubing (I used careful application of heat
from my Weller soldering iron).  Continue on with 3, 5 and 4 (remember
my order) or whatever makes sense for your coil pack arrangement.  The
final connection is to Pin 2 of the 4- pin Jetta taillight connector -
to the brown white wire position.  (This wire ends up connected to the
intake manifold ground terminal).

10.  For the coil ground, Pin No. 4 on the coil pack connector, I
followed the same procedure as with the POS grounds except the final
terminal was a ring connector that goes under the same ground connection
5 mm hex socket bolt you removed to remove the OE coil pack ground.

11. The next thing is to snap all the four pin coil pact connectors into
their respective coil packs and then push the modified coil packs down
as far as you had measured when you first trialled their installation
and heard the "click".

12.  Tie wrap the Jetta taillight connectors into the ECU POS
connectors.  Check that all your tools are out of the engine bay and
that there are no loose wires anywhere.

13.  Start the engine.  It should start right up and run smoothly.(Mine
did - Yay!!)  If it doesn't stop the engine and recheck everything - a
connection wasn't done correctly.  Find it and fix it. Continue until
the engine starts and runs fine.  Then stop the engine

14.  With the engine off but everything fine, corral the wires with the
snap-on coil pack boots, 1/4" NYLON convoluted tubing fits right into
these connectors (NOTE: DO NOT USE CHEAP POLYETHYLENE tubing - IT MELTS
(BTDT)).  On the second round, I used Taylor Sho-tuf "Chrome" convoluted
tubing in various sizes and tie wraps to corral the wiring as much as
possible.  At the Jetta taillight connectors, I used red High Temp
Silicon sealant to seal the end of the connectors.

15.  Keep a spare prepped coil pack in the trunk and enjoy.

Dave F.  Oct. 2/05 (Photo Version to come).