greetings,

I saw a post in the tech tips section of the corvette forum and have a question if I may ask.

I have an 88 vette and want to be sure my vats system doesn't crap out on me some time in the future. in the past day or so, I have be not able to start the vehicle due to the vats system as so my code reader and scanner have told me. i either waited the 4minutes or so or, disconnected the battery for less than 30 seconds and away i went. while i am aware that there could be many causes for this such as dirty or worn key/lock cylinder, i want to play it safe as not to get stranded.

I have measured the resistor pellet across two on my ignition keys and have 2 different values.the first being 4.75 k ohms and the other being 4.77 k ohms.

I have checked radio shack for these particular resistors and only find the 4.7k (being short the additional 500 ohms). how critical is the variance in the resistor pellet resistance? yes, i know i could series connect the additional resistance but, would rather not do that if i did not have to.

do I need to get a "precision" resistor to substitute in the vats system?

next question,...
what is the best way to clean the internal contacts of the lock cylinder without "insulating" the contacts from the pellet on key insertion due to "cleaner residue" which may change the resistive value the computer vat system reads when you want to start the car?

.....thanks again!

 

First question -- Don't know, but...

If you get a 4.7k resistor from radio shack, it will probably not be 4.7 k. It will be within 5 or 10% of 4.7k, depending which tolerance you buy, Now, since you are a rich Corvette owner, you could buy 10 of these things, and use the nearest to 4.76 Ohms. (probably cost as much as a whole dollar).

Or if you are careful with your money, like me, (that's careful - not tight!) you could buy one close tolerance one and see if it works.
Hate to think of spending the whole dollar all at once though.

Second question, Electrical contact spray (switch cleaner) from Radio Shack. Or isopropyl alcohol.

good luck,

john

 

i did not know how close to the "rated" resistance the computer must see to get it to function (vats). while i am not tight with my money, i hate going on a parts run and tearing things apart only to find that they don't work. will have top mortgage my house for the dollar though!

thought about the alcohol and will probably go that route.

thanks for reply! ya want to co-sighn my loan for the resistors? grin....

 

The resistor must be within 5% of the ideal value, which I believe in your case is 4700 ohms. So, your replacement would need to be from 4465 to 4935 ohms.

 

Thats it then. 2% tolerance resistor would be ideal (to hell with the expense)


Of course. My privilege.

Naturally I would have to charge a small fee, and know your kids names and where they go to school.

You understand. Just careful.

 

The actual design resistance for your key is 4.75 Ohms. This is called a #11 key. A #10 key is 3.74Ohms and a # 12 is 6.04 Ohms. I would think 4.7 would be good enough.


Some of the Corvette parts suppliers have a device which plugs into your vats wiring under the steering collum. You simply get copies of your key, cut onto non-vats key blanks and insert your working vats key into the device and hide it all up under the knee panel above the collum. Then your standard non-vats keys will start the car.

 

greetings all,

thanks for help and advice. my biggest concern was if the computer was going to be picky if the value wasn't exact and how much "tolerance" it would let me get away with.

well, anyway, went to store, bought resistor, switch, wire, hooked it up, and the computer gave me no problem whatsoever. i was aware of the tolerances of the resistor but, not of the computer......all done, works fine......thanks all......the end!...grin

 

 

OK. I'll ask the obvious. Why not take your meter to Radio Shack and try out a few until you find one that reads the same as the VATS using the same meter?

 

well, i don't need to (read above threads) as i rolled the dice and all worked out fine.