I have been obsessing on one of my Darts to get it ready to sell, and I think my Vette got jealous. I went to pull it out of the garage, and not a peep out of the engine with the key in the crank position, and yet all accessories came on when the key was released. I got out, locked it with the fob, and unlocked it with the fob, thinking maybe the securtiy system was playing with me, and still, nothing. I checked the battery voltage, and it was sitting at 12.6 volts. So...I got back in the car, turned the key, and boom, she fires right up. What the heck is up with that? I tightened the battery terminals after it started, and have rechecked it several times since, and she fires right up. This is not a good thing. My wife grows very weary, very quickly, of cars that are not predictable, and reliable, and it was her idea to buy the Vette. Isn't she a sweetie? Any ideas here would be appreciated.
As soon as the Dart is sold, I am back to playing with the Vette. I guess I just didnt; explain things well enough to her.
By the way, how do you change the battery on a 95 Vette. Does the body panel come off? Thanks for that help too.

 

I would make sure that the terminals are SPOTLESS! I have had this problem before with a layer of grime or what not on the posts that keep good contact from happening.

Another guess, if the VATS got pissed, that would describe it, too. However, it would take several minutes for VATS to reset.

 

OK I'll bite. What the heck are the VATS. How do you get them pissed? What resets them. Did I get them Pissed by working on a Mopar right next top it? It did take several minutes for me to track down my VOM. Maybe the VATS got reset in that time.

 

VATS stands for vehicle anti-theft system. Your ignition key has a pellet (a fixed resistor) in it and contacts in the ignition tumbler connect to it and the VATS module measures the resistance. If the resistance exceeds 5% from the value its supposed to be, VATS will not close the start enable relay and the starter will not crank. Also, VATS will not allow the ECM (electronic control module [the computer]) to exercise the injectors so the thief cannot push start the car. Also, if it doesn't measure the correct resistance it won't allow another try at cranking for 6 minutes. Furthermore, there is a clutch safety switch (gear selector switch if automatic) that must be closed in order for the starter to crank. The safety switch can fail, or the ignition tumbler contacts fail to make reliable connection to the pellet. If you will look in the archives you will find a great number of posts explaining how to find out the cause of a VATS related no start.

 

Thanks. That was an excellent short explanation. I now remember reading the literature talking about how succesfull the VATS system was at preventing theft of Corvettes. It did result in a dramatic reduction in thefts, so it seems like a reasonable trade off to have a minor technological clitch from time to time. It seems very likely that this was indeed what happened. That rings true to me. I tried to start another car with the wrong key once in the past, and it did behave just like this. I will look up the past threads, and study them. Thanks again.

 

One other thing-ocasionally clean your key with alcohol-works for me.

 

i agree. i have had this happen numerous times and had to clean the key and then it would start. after you have tried the first time clean the key, then you will probably have to wait about 4 minutes and it will start. this is one of the safeguards on the vats system. it has a resistor on the key. take care.

 

MAYBE VATS MAYBE NOT, First you sescribe a PERFECT scenerio for the starter to be starting to fail, they all do not click when they activate and dont start, in fact, most make no sound when they go out. Vats wouldnt have started it that quick if it was a failure. Check voltage at start when you try to start it,that would rule out Vats. Certain 95's with certain VIN# had a no start condition with a bad CCM. Would not start first time then start right up. Thats a pain if its Vats. I bet you its your starter......

 

Occassionally my 86 behaves exactly as yours does. This simply requires a battery post cleaning and tightening once every oil change. Its easier to schedule this process more frequently than wait for the problem to surface.

 

I've had the same on my 85.

Will pulling the # 25 Fuse disable the VATS ?

\db2
Carolina