tune up time, few questions

[Brett Dikeman]

At 2:07 PM -0700 8/17/02, pasquale pilato wrote:
>Hello group,
>Its time to tune up my 1990 100q.  I'm getting
>horrible fuel mileage, (hard to know for sure with
>broken odo) and the car is getting slower.  The car
>has about 120k (again an estimate)

Time to do the timing belt, if it hasn't been done already...was it
done at 60k by the previous owner?  If not, inspect -immediately-!


>   I am planing on cleaning the ISV

Not a bad idea as general maintenance, but don't expect a mileage
increase.  Use throttle body cleaner- not "carb" cleaner and not
"brake cleaner."  Throttle cleaner is designed to clean -and- lube
the throttle.  While you're in there, clean the throttle plate as
well- I find it easiest to spray the throttle cleaner in and then use
a finger+rag to wipe things down.

>  and looking for bad electrical connections.

Also not a bad idea.

>   First question is should I do something else?

What about the air and fuel filters?(and yes, the generic air filters
work fine.  Avoid K&N.)

Running a bottle of techron might also help if you determine
everything else is working OK.  Walmart sells what I -think- is the
concentrated stuff(not sure.)  Do it 1-2 tanks before an oil change.

Another mileage-reducer could be any of the calipers, but
particularly the rear calipers.  Guide pins and rusted up e-brake
mechanisms are potential sources- after a couple minutes of driving
and coasting to a stop, walk around and -carefully- check out the
temps of all 4 rotors- could be cool to the touch.

If you get stuck, maintenance has been taken care of etc- its time to
take it to a good VW/Audi shop that knows CIS; they'll be able to
check a bunch of things, like the metering system on the fuel
distributor, spray pattern+flow of the injectors, etc...


>   Second is I am going to use Bosch plat. plugs, and is there really
>a difference between the plat2 and plat 4, other than
>$2 each?

Just more electrodes to break :-)

   Single electrode plugs work just fine-keep it simple, go with what
the owner's manual recommends.  Contrary to all the hype and
marketing, spark plugs don't really do -anything- for power as long
as they're properly gapped and the rest of the ignition system is
working.  Some odd engines need odd plugs- the 20vt is one good
example...but the rest of the I-5s aren't very picky about plugs-
show me an 10v I-5 that's picky about plugs, I'll show you a 10v I-5
that has some other problem :-)


>My last questions are about the O2 sensor, I am
>looking for Bosch #13019, I hope this is correct, but
>is there any special tool I should get to remove this.

Depends upon how many wrenches you have that are that size- I was
able to change the O2 sensor on both my 5kCST and my 200q20v without
an O2 socket, but then again I seem to remember Alex M about
waist-deep into the engine compartment of his 100 trying to change
the O2 sensor or something a couple years ago- I have a picture of it
somewhere ;-)

>  I know there are O2 sensor sockets, but I do not know
>how universal they really are, nor the size.

They are universal- all O2 sensors have a standardized thread and
bolt size(well. almost all of them.)

Brett
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