I went to start my '87 yesterday I turned the key and nothing. Lights and gauges all work. I think starter I put the key in the on position jack the car up and jump the starter. The car cranks up but won't stay running. All I can think is VATS. Is there anyway to bypass it to test. I know it could be the key but with it being the holidays there is nowhere to have the key tested. thanks for any help

 

In order to bypass VATS you need to do one of the following:

wire a resistor of the same value as the resistor in your key in line where the two wires lead from the VATS control module to the ignition switch reader or:

get a VATS bypass module and hook it up to the blue wire that leads from the VATS module to the ECU. This is the wire which enables the VATS module to tell the ECU it has received signal from the key and it's OK to fire the injectors. If you do this you also need to bypass the VATS starter disable relay as the VATS bypass module only takes care of the ECU side of the system it does not bypass the starter relay part of the system.

You can also have VATS removed from the ECU PROM by having it flashed by a shop that performs PROM reprogramming. If you do this you still need to bypass the VATS starter relay.

In short the simplest way to bypass VATS is by measuring the resistor in your key then getting a resistor of the same value and installing it in line with the two wires that read the VATS key in your column (search and you will find more info on this process).

The VATS module needs to see a 30 or 50 hz square wave signal. This is to prevent someone from simply hopping in the car, hitting a few wires together and starting the car. There is no way to defeat VATS by only cutting and splicing the stock wiring.

I would try cleaning the pellet on your key with a little rubbing alcohol and a Q-tip. Grease and grime from your fingers over time builds up on the key and can make it difficult or impossible for the reader in the ignition switch to read the resistor properly.

good luck,

 

So, if it was the VATS I still wouldn't be able to crank it by jump the posts on the starter. I know VATS controls the starter and the fuel injectors thats why I think it's the VATS not giving it any gas to stay running

 

VATS disables both cranking and fuel delivery. There is a VATS module in the dash that receives a signal from the ignition key reader in the ignition switch. The VATS module is wired to both a Starter relay and the ECU. When the key reader reads the resistor on the key and it matches the resistance the VATS module is looking for the VATS module does the following:

It sends a signal to the starter relay (which is in line between batt. power and the starter solenoid) and allows the engine to crank

It sends a signal telling the ECU it's OK to fire the injectors.

So by jumping the starter the car still won't start as VATS is still disabling the fuel injectors from firing.

Yes, you could crank the engine by jumping the posts on the starter. What you are doing when you jump the posts is bypassing the VATS starter relay. You still have the Fuel Injection disable part of the VATS system to deal with.

 

This might help you understand VATS better. It's a page compliments of forum user "GIJoe":

http://www.joestradingpost.com/vats/

 

So I either have a problem at the key reader or the starter relay.

 

If the problem is actually VATS I would bet that the problem is with the key reader in the column or the resistor on the key. They wear over time and create problems. Your problem is probably not the starter relay they rarely go bad plus if your problem was the starter relay alone when you jumped the posts if you had the key in the "run" position it should have started.

When VATS gets older it can develop problems which make it act strange. I would try it a few times tonight you might find that the car will start. I'm pretty sure you have to wait some amount of time (5 to 15 minutes) between failed attempts.

 

I have been working on this for 2 days now and have tried to start it several times nothing I'm hoping it's the key. I had a '86 that had a problem with the VATS every so often the car would not crank and I would have to wait 15 minutes before I could start it up.

 

If it's VATS not allowing the car to start, the "Security" light stays lit while you turn the key to the start position instead of going out after a second or two. I had to replace the ignition cylinder in my column last month for this reason. It's not too bad of a job to DIY.

 

i had the same prob for 2 weeks, save yourself the time and dont bypass it yourself, i did it myself and the car stalled out 4 miles from my house, go on ecklers and buy the bypass blug, i think its like 20 and it take 5 min to install!

 

Excellent point - I knew the car had a way of telling you if the VATS system was causing a no start issue but I couldn't remember exactly what it was. I've bypassed the VATS in every C4 I've owned so I've never had this issue.

 

You have worn contacts in the ign lock which no longer makes reliable connection to the pellet in your ign key, or, your have a clutch safety switch (gear selector switch if automatic) that is intermittent Next time it won't crank, unplug the clutch safety switch and jump the socket and measure the voltage on the jumper to ground. If you don't get 12v in crank position, you have a VATS problem (most likely the ign lock). If you get 12v and the starter cranks, then you have a clutch safety switch problem and you can bypass the safety switch. You can replace the lock which comes with new contacts. You can bypass VATS temporarily until you get the lock replaced. If you permanently bypass VATS, you then have no protection against the 99% way that cars are stolen, bashing the column and jumping the ignition. VATS prevents that, keep your car in good repair! You can temporarily bypass VATS by removing the kick panel above the drivers feet and finding the 2 wires from above the steering column that plugs into a 2 pin connector. Unplug the 2 pin plug, insert the key and measure the resistance across the wires from the steering column. It should measure the same as the pellet and if it is more than 4% different or above 13k ohms, then you need a new lock. You can bypass VATS by connecting a 1/4 watt 5% resistor from Radio Shack that measures within 4% of your ign key pellet and connect it across the 2 pin socket from the wiring harness (goes to the VATS module).

 

I had the same problem with my 87 over the past 2 months. 9 times out of 10 it would start but the 10th time I would have to wait approx 5 mins before attempting a restart, then it would fire up. Not good for a getaway car! Found the ingnition cylinder worn and not making a good contact. The wires coming out of the cylinder were fine with no cuts or damage. I disassembled the column and replaced the cylinder. It's 100% now as of yesterday. You will need to make a bolt with a flat screwdriver slot to hold the telescopic column tight in order to unlock the spring plate. Without locking the telescopic column in place you will never be able to complete it. Then you snake the wires down trough the column. Took me an hour taking my time and approx 85 bucks worth of parts and new cut keys. good luck!

 

99.9% of the people are anti VATS.... until there car gets stolen.

It's fairly simple to replace the lock cylinder, which is the problem 99% of the time. Then you'll get another 15 years out of it.

 

If it's a VATS lockout, it should set a code 46.
http://members.shaw.ca/corvette86/Code%2046.pdf

 

Yes. The relay prevents battery voltage off the ignition switch from reaching the starter solenoid, when VATS is engaged.

The VATS also kills the fuel injectors at the same time as the starter, which is probably why the car won't stay running even after he cranks the starter directly. So yeah, in his case it seems like the car is not seeing the right pellet resistance to allow the car to be started, so the VATS is kicking in and doing it's job.

When mine did this, jumping the starter directly fired up the engine and stayed running. That proved only the starter enable relay went bad independently of the other VATS components. So my VATS was not really engaged, just a dead relay.

So what I'm saying is, it's not just a dead stater enable relay. Because if that is all it was, the engine would have stayed running when the starter was jumped directly. Rather, the VATS as a whole is keeping the car from starting by error.

 

Would the cluster even light up if the wrong resistance key was present/being seen?

 

Go here for great info on VATS.

http://vatssucks.com/

Also if you have a spare key try it to see if the pellet/resistor in the spare key makes better contact with the sensor in the ignition switch.

 

 

Well, I have ordered a ingnition cylinder today. I had the key tested and it was fine code 13. I know I will need new keys. I take it they will still be code 13 keys since the ingnition only reads the key and that changing the cyclinder won't change the VATS code because the VATS decoder can only read what code it is programed to read.