Been thinking about ordering one of these due to reading a number of stories of people being stranded due to vats. Not knowing anything about it, I'd like to see if someone has installed it already on this car. Where do I look, and what do I look for?

 

First you need to know the restistance value of the pellet on the key. Dealer can tell you. Buy the appropriate bypass unit from the aftermarket like MidAmerica or such. It's been a while since I did mine but you unplug the plug that goes from the ignition to the vats unit and plug in the bypass unit. Tricks the Vats into thinking the correct key is in the ignition. Some have a toggle switch. Mine does not. Should come with instructions.

There are those that have and those that will be stranded by this flawed system. Much better to have an aftermarket alarm or install a secret kill switch.

 

I spent about $5.00 at Radio shack for a bunch of resistors (variety pack) and made up the matching resistance for my pellet. All you need is an ohmeter or multimeter (or ask your dealer to measure the pellet for you) and a soldering iron.

Instructions are here: https://www.corvetteforum.com/techti...=153&TopicID=2

Works great and took like 20 minutes. I would recommend adding a switch to open the circuit though. Hide it somewhere and flip it when you leave the car otherwise any idiot with a big screw driver will be able to get your ride running.

 

DONT DO IT!! Unless your vats is giving you trouble..or if you get the bypass for peace of mind, just use it if you have a problem. The vats, when working properly is a nice defense against the dreaded. Remember, Vettes are very desireable for car thieves for parts and for crimes and joy rides. Protect that baby!

 

Good advice...except when I have been stuck at a pump...or in a parking lot...and had to wait for the system to reset itself. Happened once too many times to me. There are much more reliable ways to protect a car without embarrasing and temporarily stranding the rightful owner.

 

It's working fine. I didn't intend to perminately disable the system. I just want to be able to bypass it should the thing fail and not want to let me drive home sometime. So, if someone has installed such a thing already I should look for it under the dash?

 

Yep...follow the wires into the two-cavity connector at base of steering column with two black wires in the female end and one yellow and one brown wire in the male end...if it terminates in a switch box or resistor, then it is bypassed. If the wires go to the ecm, it is stock.

BTW, you aren't a corvette thief are you???

Also, it won't likely prevent you from getting home if it kicks in cuz it resets after about 4 minutes since last attempt...so if you try it again in 3 minutes, you will have to wait another 4...

 

Quick and dirty...... Gain access to the VATS module behind the bread box. Connect a jumper off the green wire from the VATS harness to ground. Done. VATS bypassed. Works on early systems 86-87.

Just remember, you now have NO VATS!

........the secretary disavows any knowledge of your actions.........

-JRC-

 

Are you serious? This works? I thought the ecm needed to see the specified resistance?

 

Look at the wiring diagram for these early models. (Ref; 1986 Corvette Shop Manual pg 8A-30-0.) The VATS module controls the Starter Enable Relay, which permits "control" power to continue thru the Clutch/Neutral lockout switch, to the Starter Soleniod. The green wire "jumper" I discussed simply provides a ground to the Enable relay that the VATS is normally providing.

The special switches sold by MAD and the like, just make it easier to hookup a bypass rather than digging behind the breadbox. Once we figured out the circuit, a switch was installed on the jumper and I got a refund.

-JRC-

 

Wow!..I hope no car thieves are lurking/learning

........the secretary disavows any knowledge of your actions.........

Thats good stuff!!

 

I don't have the diagram in front of me...so what about the other functions that the ecm ties into the vats (fail) process...like fuel pump shutdown etc.?

 

Thanks for all the answers! I'll take a look and see what my status is now. If nothing has been done yet, I'll study a little more and pick the best option for me. Thanks again.

 

I don't want to get into a pissing contest here, but I believe all this will do is make your starter work, the VATS module also disables the fuel injectors. There is a purple wire from the ECM, #963 that also needs to see a ground.

This is a topic that generates waaay too much passion. The early years of VATs, 86-88 had contacts in the key that had problems, hence people get stranded. Needless to say, that sucks. On the other hand, VATS is a pretty good theft detterent. Some say the fix is to replace the contacts in the key tumbler, some say to buy the $40 bypass kit, some say fixt the problem for $0.75 by making your own bypass and some say bypass but put a kill switch in. To top it off, it can be a difficult problem to troubleshoot since the computer will not necessarily store a code as the book says it will (trust me on this one).

Mine was acting up and I purchased a bypass kit and have had no problems since. My car stays inside of a locked hanger at an airport with 24 hour armed security, so the benifits of VATS are not so great for me. This is something that each person needs to weigh for themself knowing their own situation. At some point, I will probably change out the contacts in the column, but I am not that concerned about it. When I sell the car, I would prefer to say the problem is fixed, but there is no "right" fix to this, do what is right for you.

 

Remember folks, not all VATS are created equal. In 1990, the VATS functions were integrated into the Central Control Module software. The 90's(and later)ECMs will look for a voltage drop signal from the VATS inorder to pulse the injectors, not sure if early ECM's monitor the VATS signal. Both VATS prevents voltage from reaching the starter motor. For the later years, a two phase approach, no starter motor, and no injector pulse.

To be truthful, I suspect few thieves are looking to steal a garden variety C4. The BMW's, newer Vettes, much better return for their time/effort/risk. That said, an insurance friend told me they could part out a C4 Corvette locally about as fast as any car. The hotrod folks love the engines, transmissions, suspension, and differentials hanging on our C4's. For now, my VATS is fully operational.

Keep the greasy side down.

dlmeyers 90 coupe zf6 3speed shocks

 

OK, fair enough....

Very good! Your right. The purple and green wires both need to be grounded. I appologize for forgetting that fact as I wrote the post. The switch only needs to go on the green wire to disable the starter.

Thanks for pointing that out. BTW Nice crop duster!

 

Thanks for the compliment, but no crop dusting for that plane! That is my sky Corvette!