I have an 87 with an intermittent VATS problem. By connecting in the neccesary resistors is this correcting a problem with the chip on the key or a problem on the ignition barrell. In other words would using my spare key solve the problem? It only occurs every once in a while. Also is it true that the VATS locks out 4 minutes extra for every turn of the key? If so I`ll stop trying to start the car when it happens.

 

Standard VATS bypass provides a "loopback" that applies the same resistance as your key. You can buy a plug and play pigtail. You tie into a plug in the column harness. I just bought one, that way it's easy to return it to stock without patching up the wiring.

 

ok i`ll do that, it has an aftermarket alarm and immobiliser so i`m just gonna leave the resistors in place.

thanks for your help

 

now i cant get any resietance through the key or the spare using my multimeter?

 

i was doing it wrong:o

 

What exactly is your intermittent problem?

 

I don't know, stick the key in and try it. I'm assuming you have a "no crank" situation, meaning nothing is happening when you try to crank the car. No starter, no nothing.

Resistor method only simulates the key. If the problem is upstream with the Starter Enable Relay or the VATS Decoder Module behind the breadbox, it won't help you and car still won't start.

What you need to do stop guessing and start testing. Take your dash trim apart and drive the car like that. Then when it does not want to start, use a multi meter to see if battery voltage is getting to the Starter Enable Relay at both the two thick yellow wires on the Starter Enable Relay connector while you hold the ignition switch at the "cranking" position. If there is no voltage, then the problem is at the key. If there is voltage there, then you know the problem has nothing to do with the key or ignition switch and the problem is either the VATS Decoder Module or Starter Enable Relay. I use the metal seat tracks as a ground to test this.

Back probe and ground the green wire off the VATS Decoder Module to ground and try to start the car. If it now starts, your VATS Decoder Module is bad.

You can either just leave the green wire jumpered to ground and be done with it, or replace the VATS Decoder. The problem with wanting to replace it is that it's discontinued by GM and you have to buy it used at about $100.

Further more, These modules are matched to your key's resistance (1 -15). This means that there is only a 1 in 15 chance that the used VATS Decoder Module you buy will match your car's resistance pellet value and allow you to use your current ignition key, unless the vendor knows what the value of it was and labeled it which is unlikely. Chances are the used parts vendor will not know what the resistance value of the module they are selling you is simply because they get cars with no keys to them, in pieces, etc so it's a total clusterf**k.

Then you have to hire a locksmith use a device to determine your new module's value and make you a new key which drives the price up. Total PITA. The used module will run you about $100 not including the cost of a locksmith for new keys.

If car still won't start with Green wire (top most on harness) on VATS Decoder Module grounded, remove the Starter Enable Relay and jump the outer two terminals with a wire and repeat (see pic below). If it now starts, replace your Starter Enable Relay.

$20 at the dealer. Delco part#14093107 I got an extra one if you need it.

If it still won't start, check the clutch safety switch if your got a manual trans. If auto, try with shift lever in Neutral.

Starter enable relay:


VATS decoder module:


Bypassing Starter Enable Relay:


Testing for battery voltage with switch in "crank" position at each of the two thick yellow wires. Each should have battery voltage.

 

It is true that if the VATS manual doesn't see the correct resistance when you attempt a crank, it prevents cranking for 4 minutes. The time to measure the resistance at the wires from the steering column is when it won't crank. You can also try your spare key. The contacts in the lock cylinder don't last forever, my 87 with 220k is waiting for its second tumbler since I've owned it, it wouldn't start last Friday. I only bypass it with a resistor because its my DD and I am waiting for a new cylinder to arrive. I recommend that you don't permanently bypass VATS because 99% of thefts are done by bashing the column and jumping the ignition. VATS saved the vette of the person I bought my 87 from.
Be aware that the clutch safety switch (gear selector sw if auto) can also prevent the starter from cranking. Next time it won't crank, bypass the clutch safety switch.

 

Each failled crank attempt does not add delay minutes on top of the previous ones, it just starts back from the beginning each time. I think it's 4 minutes.

 

...freakin' EXCELLENT picts!