Well my friend got his first Miata, a 90 Mariner with 186 on the clock, no rust, and a bad top for $800.

So naturally he brings it over to me, and naturally I ask to drive it. Him being extremely protective of his baby doesn't give me the keys, but lets me sit in the driver's seat. So as a 'why-not-let's-mess-with-him' type thing, I take out my keys, and put my 90 key in his car. Both of us thought that nothing would happen so he didn't stop me. To both of our surprises it starts the freaking car.

I checked the vins, and both of ours were made in the same plant at around the same time. His however, is from Florida where it was registered originally.

So my question is: how many possible keys are there for a 90 Miata? I always thought that each car had its own unique key, but I guess I was wrong.

 

This sounds like a question for the Mnet NA forum, so I am transferring it over there:gay:

 

Thats a good question, I would be interested in hearing that too.

We lost the key to one of our chassis a while back, tried using keys from all the other chassiss and our own Miatas, but none of them worked.. Looks like you just got really really lucky!

 

I've owned many late 60s-early 70s GM vehicles, and have seen this many times, both with my own cars, and also at shows and meets. I know with a particular Cutlass I owned, there were only 12 key combinations for the year.

Know that doesn't answer your specific question, but I would suspect that there would be a similar (small number) of key codes. One of the reasons for the emergence of electronic immobilizers added to keys.

 

Or maybe the lock cylinder has been gutted

 

No, but both of our keys are close to identical. His is a more worn than mine, but the same basic shape is there.

 

At least now you know that a spare key is just one call to your friend away..

 

And he knows that a spare car is just 10 minutes away.

I think I'm going to swap out the entire ignition cylinder between two of my cars. How hard is it to do that?

 

LOL didn't even think about that one..

Let me know if you need a new cylinder/key set.

 

I think I'm going to go with a bit of a different approach. I'm going to install a remote kill switch.

Instead of unlocking my doors, I'll have a door actuator flip a kill switch wired from the battery in a custom box behind my spare tire. Also, since it's a 90, I don't have a remote trunk release, so getting in the trunk without massive cutting is close to impossible. Then I'll just run a wire from my radio to the battery so my presets are all saved.

What does everyone think? Any computer issues possibly?

 

i had that happen to two friend who both had old, red nissan trucks.

 

as they wear they tend to get less and less particular.

 

What i'm thinking.


There's a fleet of golf carts where I work. My cart-specific key can start a few of the older ones.

 

My mom worked for a rental car company MANY MOONS ago. She constantly had to go and bring keys out to customers cause they would jump into the first Caprice (or whatever the type they rented) they saw and start it and drive away thinking they had the right car. Then they would get out and lock the door behind them (not locked on the lot). They would come back and not be able to unlock the door cause they got in the wrong car. Seems most american models had a universal ignition but specific door locks. So as long as you had the same make/model/yr, it would start it, but wouldn't unlock it.

 

Wow. Whatever saves 3 cents..

 

There would be a much easier way to accomplish what you are trying to do. An easier option would be get the pinout of your ECU, find the CAM angle sensor wire, and put a switch on it. It will allow the car to crank, but will never start - if the ECU seens no cam angle signal, it will cut spark and fuel too I believe. That way you would hear *Chudadudududududududududududududududuududud* of someone trying to start your car, but they never would get anywhere. I have a swich on my CAS signal wire, but its a normally closed momentary switch, so I can hold it down when cranking the car on startup in the morning to build oil pressure. If you want to get really stealthy, you could use a cruise control switch (assuming you dont have CC or have taken it out), and wire that to the CAS signal wire. Wouldnt be any switches out of the ordinary for someone to find and switch.

 

I bet the tumblers are just worn...

I used to have a Gov job with a GM 'master key' if it said US Army on it, I could open the door and drive away (it worked in Germany too)..

 

My CC switch (90 base model) actually is my garage door opener.

 

my family used to have a ford contour.....

one day my mom left Target, hopped into a green contour like ours, went to start it.... and was then startled by the cars angry owner that thought she was trying to steal it!!!!!

turned out she was in the wrong contour..... and her key just happened to work, the other owners key also worked in her door, so it wasn't a worn cylinder issue!