VATS Gothcha's

[zr1don]

I just got my Z running again after an unanticipated 3 days of troubleshooting. I had the steering column out to replace parts contributing to "tilt column looseness/play" problem. after reassembling and reinstalling the column, I had the dreaded "no start" problem. Turn the key, nothing happens, interior lights dim, no cranking starter. I immediately think VATS, so I check the starter enable relay and the fuel enable signal from the CCM to the ECM. Both circuits are supposed to be taken to ground in the CCM. I can run a jumper to ground on both circuits and get the starter and fuel pumps to work. I now know the problem but what is the solution. Adding to my indicision is that I have disabled the VATS system in the ECM (what exactly does that do?). I try to use the troubleshooting charts in the FSM, but get no clear culprit. While I'm in there, I replace the ignition switch and the key lock cylinder. When I get everything installed and ready, turn the key and still no start. Back to the FSM, reading the system discription for the "theft deterrent system" I find this "pearl": if an unauthorized key is used the system will disable the starter and fuel for 3 minutes, if attempt is made to start prior to the expiration of the 3 min the system adds an addional 3 mins for each attempt. The culmative "time out" period cannot be reset (even disconnecting the battery does nothing the time out simply continues when the battery is reconnected. I have no idea how many unauthorised attempts I made trying to start the car, I do know it took checking the key lock cylinder and ignition switch for proper operation after reinstallation, hooking up the battery and letting the system set for 30 mins befor attempting a start for it to work. Oh, I also found that leaving the key in the ignition during the "rest" period does not work, the key must be removed for the theft system to reset.

This is probably way to much info for a simple conclusion "VATS SUCKS"!!!

Hope this helps somebody avoid some of the many, many mistakes I made.

[tccrab]

You're not the first to say:

http://www.vatssucks.com/

Yup, there's even a web site about it.

TomC
'Crabs

[gbrtng]

I follow what you did but do not understand why there was no start in the beginning.
What did you fix so that it would start?

[ZR1Vette]

This is a fairly interesting read>>
http://vats.likeabigdog.com/

[zr1don]

My oringinal key lock cylinder was apparently not reading the resister in the key, when I ohmed the circuit, I got infinite ohms at the first connector after the key lock cylinder - should have read 9,530 ohms for a #14 key. I replaced the ignition switch just cuz. Anyway, because there was an open in the key lock cylinder circuit, it was considered an unauthorised key and went into the antitheft mode. After I replaced the lock cylinder, there was still a wait period stored in the ccm and I had to connect the battery and wait for the wait period to countdown befor I could start.

Hope that explains what I did.

[zr1don]

Oh, by the way, I also found the info posted by ZR1Vette and did the installation of resisters in the key lock cylinder circuit to eliminate any future chance of a failure.

[gbrtng]

Originally Posted by zr1don

My oringinal key lock cylinder was apparently not reading the resister in the key, when I ohmed the circuit, I got infinite ohms at the first connector after the key lock cylinder - should have read 9,530 ohms for a #14 key. I replaced the ignition switch just cuz. Anyway, because there was an open in the key lock cylinder circuit, it was considered an unauthorised key and went into the antitheft mode. After I replaced the lock cylinder, there was still a wait period stored in the ccm and I had to connect the battery and wait for the wait period to countdown befor I could start.

Hope that explains what I did.

Yup, that explains everything - unfortunately, that's not an uncommon failure. The 86s were notorious and a service bulletin was issued using redesigned parts which (apparently) weren't redesigned well enough.