Location: I was a lonely, teenage broncin' buck, with a pink carnation and a pickup truck
How do I diagnose VATS?
I posted about a no start, in my new '91, about a week ago. It did it again tonight.
I did some research in between, because my previous '85 didn't have VATS. I didn't know about the wait in between starts. So this time, I waited ten full minutes, and nothing. Waited ten minutes again, and nothing. So....waited fifteen minutes, and she started!
So how do I figure out what is causing the VATS to prevent a start. The key seems fine, and I made sure it was clean and dry. I think the ignition switch has been replaced, because there is a switch and key in a Delco box in the glove box.
I realize I can put a resistor in line somewhere under the dash, to bypass it altogether, but I would prefer to fix it.
Any thoughts?
Thanks!
In the primary wiring bundle that ends at the ECM is a purple wire, probably an 8-gauge wire I'd guess, it's definately larger than the other wires - this wire is the hot wire that goes to your starter solenoid with the starter. To fix your problem, simply bypass that purple wire with a 30-amp relay switch. The 30-amp relay switch will directly connect the starter solenoid with the battery when you start the car. This way, you still have your VATS and your car will still start. Now if you do this and your car still doesn't start, then you do have a VATS issue and probably need to get a new key.
I spent months trying to figure out the same problem on my ZR1, and tracked it down to a voltage drain somewhere between the steering column and the solenoid. I'm pretty sure the VATS when engaged cuts off all power, in which case you shouldn't have a voltage at all in the purple wire when you turn the key over. I, however, got a voltage every time I tested it when my ZR1 wouldn't start. For some reason I was getting about 6-7 volts, which was too low to pop the solenoid.
It's been 3.5-years now since I installed the relay, it's started every time and the starter has been in there for over 4-years now.
Before expending a great deal of time on the vats jumper around the clutch safety switch first. Remove the driver hush panel and find the connector with a purple and black wire in it and unplug it and jumper it at the connector. If this does not work then you can chase the vats or starter.
Installing the relay only takes 10-minutes and it's all done by the ECM, all you need to do is move aside or unplug the ECM. You can try either one first though, it's up to you.
Many people have banked on this nutorious starting problem being the VATS or clutch safety switch. I've been through both and I still dead ended, and with the same symptoms, and found the problem to be an unknown voltage drain somewhere in between the key and the starter solenoid. I really think there is a wire somewhere in there that's too small to carry the necessary power to activate the solenoid.
I know it's frustrating, I've wanted to set my ZR1 on fire from being so frustrated with it not starting. Not to worry, one of these two checks I'm positive will fix your problem for good.
most of the time it the ignition lock cylinder wires are frayed or broken connect an ohm meter to the vats harness under drivers dash panel you will get ohm reading if not you found the problem turn the ignition key and see if you lose your reading if you do the wires are broken . very common problem
Usually when you put your key in, the security light will go out once you turn it. If it stays on - then there is a fault with the key or the cylinder.
Location: This city NEVER sleeps! Frank's back yard!
Quote:
Originally Posted by Aaron71771
Usually when you put your key in, the security light will go out once you turn it. If it stays on - then there is a fault with the key or the cylinder.
BINGO! This little piece of information is the REAL diagnostic way to determine if it is VATS or something else. Is the security light on steady while cranking?
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How do I diagnose VATS?
