Hey all, I've had this intermittent problem for years, but it looks like it finally broke for good. Car won't crank at all, i know it's not the starter b/c i wired the solenoid directly to the HOT battery terminal and it will crank, but still won't fire up. Looking through my Chilton manual schematic, it looks like there is a pass-code decoder module, and a starter enable relay that could potentially be faulty. Can someone help me locate these parts so i can troubleshoot? Thank you

 

Of course i just tried it today and it fired right up...... I was just reading through the forums, someone said that the next time it happens i can pull out the EEPROM and see if it starts - if it does, that means it is a VATS issue. Maybe i'll just disable the VATS if that's the problem.

Let me know what you all think, thanks!

 

Is the security light on the dash lighting up when it doesn't start?
How worn is your key? A well worn key often doesn't make a good contact. Bad contact - greater resistance, and VATS thinks it's the wrong key.
The other 'wear' part is the lock cylinder.
VATS does two things. If the key isn't correct it won't let the computer fire the injectors, and it doesn't switch the relay so the starter won't crank. You can bypass the relay, which would let the starter crank, but won't solve the ECM part of it.

VATS is easy. It's no easier to bypass it than to fix it.

 

The connector for the VATS ignition switch is right under the column - it's an orange wire with a two pin connector. You just cut the wire in the chassis side and wire in a resistor that matches the pellet in the key. Problem solved.

GD

 

Drew -
I'm not sure i have a security light, but i'll double check next time.
Key is not worn, it is fairly new, I do have a backup key i can try next time it happens
I was thinking the same thing about the lock cylinder, it definitely has a lot of play in it. Is there a way to test it to make sure its good?
Last time it happened, i ran a wire from the starter solenoid directly to the battery and when i connected it, the starter cranked but the engine wouldn't fire up. I tried this a few times with the key in the ON position with no success, i could smell fuel though so i'm not sure the injectors were disabled

GeneralDisorder -
OK, i'll remove the panel under the steering column and see if i can test the wire. When i turn the ignition, i would assume the wire should measure a certain voltage that it sends to the pass-key decoder module. At least that should help me narrow down the issue.

Thanks a lot for your responses guys, the car also has 265,000+ miles and i believe all these components are original, if that helps.

 

The pellet in the key is a resistor. Measure the resistance from one side of the key to the other. Note the value. Then put the key in the ignition lock, no need to start the car or turn to run, just slip it in. Unplug the connector in the big orange wire (actually two tiny white wires inside an orange tube), check the resistance between the terminals on the column side of the connector. If it's wildly different than the key, there's a connection problem.

If VATS disables the system, the security light will come on and stay on.

 

*Update

Okay, so i just disconnected the VATS and the same exact thing happened where i turn the key and no crank. I tried starting the car with the jumper wire i ran from the starter solenoid and it wouldn't start either with the VATS harness disconnected (big surprise). Re-connected it, and it starts fine.

Any idea what the 2 wires should measure? Is it supposed to be the resistance in ohms from the key? If yes, i'll verify the correct resistance is being measured to rule out the lock cylinder not sending consistent resistance....

 

It's VERY simple. The resistor IS the key. You measure the key. Then you put the same resistance value read from the key between the two wires that ran to the switch. Turn key, start engine, move on. There are only 14 resistance values possible. Google the VATS resistor values table. You can buy a pack of all the possible resistors for about $8 on ebay.

GD

 

I understand, i was able to measure the resistance on the key and match it up to the wires under the steering column. My issue is, this problem is intermittent, so i’m not sure if the incorrect resistance is being sent to the module sometimes, or the module isn’t reading it and sending the OK to the ECM. At least i understand the system a little better now, hopefully the problem will surface again and i can narrow it down without pulling the dash apart???

 

99% of the time the problem is the interface with the 200lb gorilla. The contacts and rotating bits inside the ignition lock assembly. That's why they sell the resistors.

Alternatively you can burn a chip to delete VATS from the ECM and jumper out the starter solenoid relay (easy to get to).

My recent 91 formula came with no keys and a drilled out ignition lock. I burned a chip, jumped out the starter relay and had it running in about 15 minutes.

GD

 

Gotta ask , what dolt did the dopey drill job , a super low skills car thief or a ham fisted lost keys owner ?

 

The resister goes in the HARNESS side of the unplugged multiple connector, NOT the side going up into the steering column lock cylinder. Just to clarify.

 

You can wire in a resistor to take the place of the key and lock cylinder. Or you can replace the lock cylinder, and have a new VATS key blank with the proper resistance cut to match the new blank, and you keep the added security of VATS. Without a functioning VATS system, it takes about 30 seconds for a thief to crack the column and drive away. It's your call but VATS is an easy system to fix, and it does stop the joy riders.

 

On my two, 1996 Impala SS's I installed new lock cylinders assemblies, to maintain the VATS System.

 

The owner's kid attempted this (he's about 30 and has no license). Apparently there was a house break in and the thief stole the jewelry box that had the VATS keys in it. They needed to move the car out of the garage so after unsuccessfully prying with a screwdriver around the airbag yielded no obvious way in (but nicely destroyed the horn button ears, etc), out came the rotary ****ulator.... they did get it to turn and unlock the steering to move it. Just left all the shavings and bits of lock cylinder all over the carpeting. Super awesome.

GD