Just don't give them the car keys.  To be honest if you can't leave car
keys around the house you have bigger problems than controlling use of
the car.

Sleep in the car?  tie up your kids?  Maybe you should tell them if they
joy-ride, you'll call the cops and let them spend the night in jail.

All seriousness aside, you could pull the fuse for the ignition or the ECM.

-Bruce

An interesting problem.  Most parents find that discipline and/or
decent physical control of the car keys is sufficient.  But I can
imagine situations where you might be worried that even an occasional
lapse is likely to leave you standing on the sidewalk watching your own
taillights get smaller in the distance. (Examples include especially
rebellious teenagers, special-needs kids who can't see the consequences
of their actions very well, and some little boys who just get into
everything -- what if they stuck the car keys into the car instead of
into the electric outlet like I did?)  There are some simple mechanical
measures you can take.

Any hardware or bicycle store should have a sort of wire rope with a
loop on each end, and a resettable combination padlock.  Use it to
prevent the wheel or the shifter from being moved much (just how you do
this depends on the vehicle).  It can do double duty in helping
discourage vehicle theft, at least by anybody who doesn't have the
chutzpah to walk around with a hacksaw or bolt cutters.

There may also be a combination version of the "club" by now.

Ttry to figure out a way to use these things to prevent them from
rolling the car around in neutral or somesuch -- being able to set it
in motion but unable to control it would be even worse.  That's where
the cable lock idea might be especially good, if you can figure out how
to keep the shifter in Park with it.

Many motorcyclists and some car enthusiasts use a cable lock (usually
one of the especially large and formidable-looking ones)
through a wheel as well.  Don't forget it's there and drive off with
it, though -- some significant damage could result.   Also, these are
generally based on keyed rather than combination locks, and if the kids
can purloin the car keys they can probably get whatever other keys they
want (also a disadvantage of those very strong U-shaped bicycle locks).

Best of luck,
--Joe

A leather belt should do the trick.

If you have to worry about your kids doing this, then messing with the car
to try to prevent it is a little like shoving a cork in the tailpipe to
"solve" exhaust smoke. You're looking at the symptom when you should be
focusing on the problem. Sit the kids down. Carefully explain to them the
consequences of joyriding. Be sure to include not only the consequences
*you* will apply, but also the consequences *the law* will apply, as well
as the recursive consequences if their joyride should involve injury,
death and/or property damage. If you're still worried that they'll
joyride, then you've no business leaving them in a position to be able to
do so.

("Buck Turgidson" <jc_va@hotmail.com>) scribbled:

<-------------- Troll O Meter --------------->
+----+----+----+----+----+----+----+----+----+
1    2    3    4    5    6    7    8    9    10
...^

I joyrode (is that a word?) every one of my parents cars as a kid.  I
learned a lot about mechanics, avoiding the police, insane cornering,
and minute long donuts in that time.  I was a troubled teen, but in the
long run, things worked themselves out and I eventually became a
respectable adult.  Sometimes good comes from seemingly nowhere; in my
case it was my parents' strong values that took an EXTRA long time to
sink in.  My relatively slow maturity rate didn't help any either.

Toyota MDT in MO

"Buck Turgidson" <jc_va@hotmail.com> wrote in message

Wire the coil output wire under the driver seat. For a distributorless
van like your with 70k volts, that is a liability. Instead, put a dummy fuse
(that doesn't look blown) on the ECM.

We'd adopted an ADD boy with great biological parents. If we hid the
keys or if he knew that we'd removed the fuse, he would come after us
with a knife. He is still searching for his biological parents to take revenge
for abandoning him. No worry- he'd just turned 18 in jail.

(sorry if this a double post - having isuess posting this am)

You have two problems.

1. Lack of discipline. Define clear boundaries and consequences for
stepping over the line. Follow through. The threat of losing the keys
is enough to make most teenageers think twice.

2. Lack of information. When you are out of the house for an extended
period of time you may not know if the kids violated your rules or not.
Fit a Davis Carchip and you will know if the car was used (or the chip
disabled) while you were out. Then you can discipline accordingly. With
this device you can also monitor their driving habits for 'authorized'
trips also.

You don't want to prevent them making bad choices, you want to catch
them. They have to learn what occurs after they make a bad choice,
otherwise they will never learn.

JP

Buck, I think the concensus is clear.  You need to disempower your
kids, not disable the car.

Swing some cojones, and strike a blow for a responsible younger
generation.