maciu

My story:

To remove t-belt plastic cover you have to
remove ribbed belt rensioner. Then just
unscrew airduct and wiggle it a little bit
to have more room for camshaft sprocket screw.
I was unable to remove it completely, I wonder
how author of previous procedure did this.

Machining 23mm socket to be much smaller
(sprocket screw needs only 5-6mm deep socket)
helps a lot.

Unscrew all of the spark plugs and both CKP and RPM
sensors. Using 23mm socket with extension
turn crank to match upper (camshaft sprocket)
and lower (belt pulley, lower guard) timing
marks, checking for 0 mark on flywheel is not
necessary, some of you may even not have it at all.

Now with screwdiver inserted through opening
where normally CKP and RPM sensors are, block
crank and loose sprocket screw.

Mark rib on timing belt where is upper timing
mark and take sprocket with belt off, you don't
have to tension it at all times, in fact
sprocket alone will be helpful later.
<a href="http://i13.photobucket.com/albums/a258/maciu/Audi/C4%20S4/Motronic%20And%20Sensors/CPS%20-%20Hall%20Sender/DSC07567.jpg">But at first I did secure belt to sprocket
and tension the whole thing.</a>
It is not necessary.

Then unscrew CPS bracket, plastic trim screw,
and gently remove CPS (mine bracket didn't break).

Do all the necessary work (soldering, cleaning
etc.) with new CPS.
<a href="http://i13.photobucket.com/albums/a258/maciu/Audi/C4%20S4/Motronic%20And%20Sensors/CPS%20-%20Hall%20Sender/DSC07572.jpg">This is the result.
As you can see I've used RPM sensor plug.</a>

I have also cleaned the whole place with brake
cleaner. You shouldn't worry about t-belt
because all of the cleaner will drip behind
plastic cover besides it vaporizes quickly.
<a href="http://i13.photobucket.com/albums/a258/maciu/Audi/C4%20S4/Motronic%20And%20Sensors/CPS%20-%20Hall%20Sender/DSC07570.jpg">Before.</a> <a href="http://i13.photobucket.com/albums/a258/maciu/Audi/C4%20S4/Motronic%20And%20Sensors/CPS%20-%20Hall%20Sender/DSC07577.jpg">After.</a>


Now reinstalling everything:

Put t-belt on the sprocket and try to install
it on camshaft. You may not be able to tension
belt enough to snap it on easily.
Using sprocket alone I tried different camshaft
positions (very small movements actually) and
I've found perfect one - almost no tension was
required to put sprocket back on cam.
Everyone should be able to do it if
timing belt is not overtensioned.

Now put some locking compound on sprocket screw
and again block crank, tighten screw.

Later I turn crank using upper cam screw few
times checking timing marks and everything
was perfect.

The rest is just reverse.

Maybe it's not the prefect procedure but it has
at least two advantages over the previous one:

- you don't need any swearing friends to help you
- gives you yet another occasion to make sure
your spark plugs are properly torqued

It's good to replace ribbed belt tensioner
screws at that time or at least use some anti-seize
for them, mine were rusty and I had some problems
unscrewing them.

Hope it will help someone, someday.

<a href="http://s13.photobucket.com/albums/a258/maciu/Audi/C4%20S4/Motronic%20And%20Sensors/CPS%20-%20Hall%20Sender/">All pics</a><ul><li><a href="https://forums.audiworld.com/s4s6/msgs/149826.phtml">Original CPS procedure link</a></li></ul>

UrS4boy

Perfect. I've added a link to this in the FAQ. Thanks very much.

SpencerB

The ties held the belt in place fine when you took tension off it. CPS is pretty easy to replace, I replaced mine around 100K to prevent the possiblity that it could fail soon and leave my stranded.

Chapel

we did it today. Prior to install, we were getting spark.
wired it EXACTLY as needed. installed it (as preventative) and NOW no spark and a 2113 code.

it's wired red-red, black-black, green-green... and NOTHING.

and my OE one is all hacked up now (from removing the rivets)
so, now rather than trying it again with my SECOND one, I'm gonna shell out for an OEM one and do the job twice in a week