hi im new to this forum, i work for hofker automotive in knoxville tn,and we do lots of repairs and restores to corvette's.although this is a verry unusuall case indeed. im working on a 1987 vettte with the vats chip key system.the problem is the decoder module is not working and they have discontinued making them i have had no luck in finding one anywhere, the question i have is ,anyone else had this problem and if so how did u remedy it. i am right now trying to make a 85 ecm work with this system with minimal luck.on the orig system the vats module sent a 2.5 vold modulated pulse to the ecm.i tried just a 2.5 v reference but it did not work, also have replaced the org ecm still no luck. its beginning to look hopeless,i tryed to get the customer to convert to 4 bbl but he wants it all stock.anyone have any ideas???
if u have any and it doesnt show it here my email is performanceaudio@comcast.net

 

You can disable the VATS function entirely via re-programming the PROM chip.

 

ecm outputs a 5 v signal and looks for a 30 hz sink to enable injectors...if the sink is 50% duty cycle, a vom will show 2.5 v.

there are several vendors on line that sell 30 hz generators ....i built my own, takes less than $10 of raddyshack parts + soldering time, send me a sase if you want the schematic.

the vats module also controls a relay in the starter circuit--you can simply jumper that.

 

omg u guys are great ive been workin on this for a month lol i hate gm security systems.if i choose to reprogram what do i need to do that, i know our snap on brick and solus cant do it there just scanners.
at this point im ready to try anything including a rag in the tank and a light
this cars (customer) has drove me nuts. esp when u got a person w/ money and wanting to spend it at ur shop and u cant fix it.

 

For programming, there are a number of ways to go.

You'll need editing software (this program will allow you to view the parameters set in the PROM chip, change them, and save them). Two very popular programs are TunerPro and TunerCat.

You'll also need hardware, in the form of a programmer. This is the device that you will send the updated PROM information to, in the form of a binary or "bin" file. The programmer can then upload this data onto a memory chip, which replaces the stock chip.

There are a few other things involved, depending on what you plan to do, etc, but that covers the basics.

I use TunerPro RT and a unit called the AutoProm. This set up has the additional feature of allowing me to make changes in real time (while the car is running), but is definitely not necessary. I HIGHLY recommend checking out Moates.net. You can find everything you need there, the products are great, and you won't find a better, more knowledgeable guy than Craig Moates. His customer support is second to none!! He can definitely set you up with the equipment you need based on your intentions.

I hear ya about the fire rag, though. Many times I've considered pushing my money pit out the garage and into the neighbors rock wall!

 

he he well one good thing i guess. around here u cant junk them even if there complet w/motor they say the fiberglass outweighs the metal lol so they wont buy them for scrap, lol i already called in case this customer leaves me stuck with it.anyone also have a idea where to get a top for this car the dumbasses that towed it in put it backwards on a rollback with the top not serewed down so u can imagine the rest.