Can someone explain to me how I can build a VATS bypass?

I assume that it is only $5 or less in Radio Shack parts, correct?

 

I have one of the Baker Electronics boxes sitting in my toolbox if you want it. It's doing me no good since I turned it off in the PCM. I just needed it to get the car started before I got HPTuners.

PM me an address and it's yours. Merry Christmas!

-Matt

 

theres a couple ways to do it.

heres how it works:

there is a VATS module. this module looks for a specific resistance between two wires. the key has a resistor in it.
when you put the key in the column, contacts connect that resistor to two thin wires. these wires go back into the vats module

assuming its the correct key, the VATS module sends a specific square wave frequency into the PCM. when the PCM sees this, it allows the engine to run. without it, the engine never runs.


there are three ways to easily bypass it.

1. measure the resistance the correct key has. buy a resistor that matches it, and connect it between the two contact wires leading into the VATS system. this lets it think the key is there... of course for this to work, you have to have the VATS box, and the key.

2. make a simple circuit (a 555timer one would do easily) and send the signal directly to the PCM. this is what most of thoes "vats delete" boxes are.

3. edit the PCM code to delete vats... using HP tuners or LS1 edit, its a simple uncheck of a box.

 

wow nice guy...

 

The C3 guys on Corvette Forum have a 20 page thread of people just doing this type of thing. If you have something that you don't need, you post it up, and the first person to reply gets it. Sender pays shipping. It's kind of a "pay it forward" thing for the holidays.

 

Its very easy. Here is the schematic I used. There is one caveat. The R2 resistor should be 12.2K ( 10K + 2.2K) ohm for passkeyII systems. The 2 values represent the older and newer pass key systems, the older ones used a 30hz signal where as the newer one use a 50hz signal. This diagram will create the 30hz signal for the older passkey I systems without the chagne to R2. I used 12.5K ohm and it worked just fine, there is a tolerance on the frequency.

The actualy cost was probably $5, but you can't just buy the exact quantity you need from Radio Shack, so expect to spend around $15, but you'll have enough parts to make 2 or 3 with the exception of the 555 timer chip, you buy those individually.

here are 2 links for reference:

Dont' be confused by the labeling, in the image, C3 is the capacitor the calculator below uses as C1.

-Marc

http://home.cogeco.ca/~rpaisley4/LM555.html#2

http://home.hiwaay.net/~davida1/passkey.htm

 

I actually found a vats module from a salvage yard car, lt1, ls1 or caprice. Mine is a caprice and worked fine. I have a friend at a gm dealership who ran the numbers and gave me the key code and i looked up resistance there. All you have to do from there is solder a resister in place, hook up a key on, battery hot, ground and the vats signal wire. works perfect.

 

Payne,
The big brown truck should be delivering you a present in a few days. I'll PM you the tracking number.

-Matt

 

Thanks so much Matt.

The paypal truck should deliver you enough for a case, for all the help.

-Jason

 

Hey Scooter , I sure could use a Corvette , and I'll come pick it up to save shipping.