Defeat VATS Without Modifying PROM?
01-12-2001, 03:45 PM
#1
Junior Member
Thread Starter
Join Date: Jan 2001
Location: Magnolia, TX, USA
Posts: 38
Likes: 0
Received 0 Likes
on
0 Posts
Defeat VATS Without Modifying PROM?
Apparently, most people who do not wish to deal with the GM VATS have all the VATS-associated equipment on the vehicle, and the greatest challenge is finding a resistor which matches the one in the original key. Unfortunately, I do not have such luxuries. I am trying to get around a 1986 'vette VATS, and all I have is ECM 1227165 and the original PROM. I found somewhere that a 50hz signal is emitted on the ignition circuit by the VATS decoder module, and that this can be created using an oscillator. Does this seem plausible to anyone? I am not having problems with the starter, since that circuit is independent, but the injectors on my system shut off after about 2 seconds and the ECM stores code 46. Any ideas on how I can get around this? My installation is from a 1987 L98 GTA, and I am using it in a 1988 GMC 1/2 ton truck. If the Passkey systems from 1986-1989 are similar, any reasonably simple means of defeating VATS would be useful, since this would enable me to use any MAF ECM. Thanks.
01-13-2001, 02:19 PM
#3
Supreme Member
Join Date: Jun 2000
Location: In reality
Posts: 7,554
Likes: 0
Received 1 Like
on
1 Post
Car: An Ol Buick
Engine: Vsick
Transmission: Janis Tranny Yank Converter
Originally posted by 87/88Firetruck:
Apparently, most people who do not wish to deal with the GM VATS have all the VATS-associated equipment on the vehicle, and the greatest challenge is finding a resistor which matches the one in the original key. Unfortunately, I do not have such luxuries. I am trying to get around a 1986 'vette VATS, and all I have is ECM 1227165 and the original PROM. I found somewhere that a 50hz signal is emitted on the ignition circuit by the VATS decoder module, and that this can be created using an oscillator. Does this seem plausible to anyone? I am not having problems with the starter, since that circuit is independent, but the injectors on my system shut off after about 2 seconds and the ECM stores code 46. Any ideas on how I can get around this? My installation is from a 1987 L98 GTA, and I am using it in a 1988 GMC 1/2 ton truck. If the Passkey systems from 1986-1989 are similar, any reasonably simple means of defeating VATS would be useful, since this would enable me to use any MAF ECM. Thanks.
Apparently, most people who do not wish to deal with the GM VATS have all the VATS-associated equipment on the vehicle, and the greatest challenge is finding a resistor which matches the one in the original key. Unfortunately, I do not have such luxuries. I am trying to get around a 1986 'vette VATS, and all I have is ECM 1227165 and the original PROM. I found somewhere that a 50hz signal is emitted on the ignition circuit by the VATS decoder module, and that this can be created using an oscillator. Does this seem plausible to anyone? I am not having problems with the starter, since that circuit is independent, but the injectors on my system shut off after about 2 seconds and the ECM stores code 46. Any ideas on how I can get around this? My installation is from a 1987 L98 GTA, and I am using it in a 1988 GMC 1/2 ton truck. If the Passkey systems from 1986-1989 are similar, any reasonably simple means of defeating VATS would be useful, since this would enable me to use any MAF ECM. Thanks.
Double the speed and use a flip flop to get the 50% DC
555 running off a 7805 (?) it's a little 3 pin voltage regulator. Use a 10 Mfd cap on the Input side to the 555.
04-24-2011, 02:58 PM
#6
Junior Member
Join Date: Apr 2010
Posts: 2
Likes: 0
Received 0 Likes
on
0 Posts
Re: Defeat VATS Without Modifying PROM?
im having the same problem with the code 46 everything work except injectors arent feeding the fuel really aggrevating beings my car is stuck in front of gmas house and people have been trying to break in to it really sux
04-25-2011, 09:28 PM
#7
Supreme Member
iTrader: (1)
Join Date: May 2004
Location: houston
Posts: 2,262
Likes: 0
Received 0 Likes
on
0 Posts
Car: 83 POS monte carlo 2015 chevy P/U
Engine: 92 5.7 tpi 5.3
Transmission: 700r4 6L60E
Axle/Gears: 2.42 too high
Re: Defeat VATS Without Modifying PROM?
odds are the VATS wiring going to the key lock cylinder are bad near the lock cylinder. its a very common problem with the VATS.
if that is in fact your problem, you can replace the lock cylinder and get 2 new ignition keys to match the resistor of your old keys but cut for the new cylinder.
or you can build a bypass harness to bypass the lock cylinder.
you can get or build a bypass module that would make the ECM think the VATS system is working, but you would also have to bypass the starter relay.
you can have the VATS removed from the chip by burning a new chip with VATS disabled, again you would also have to bypass the starter relay.
if you do decide to replace the lock cylinder, be certain to buy a Delco lock
cylinder. the aftermarket lock cylinders are trouble prone and won't last like they should. where i used to work at, we tried the aftermarket cylinders a few times and always had to replace them within a few months with Delco lock cylinders and keys.
2 good pages of VATS info and trouble shooting,
https://www.thirdgen.org/vats
https://www.thirdgen.org/vats_passkey_system
if that is in fact your problem, you can replace the lock cylinder and get 2 new ignition keys to match the resistor of your old keys but cut for the new cylinder.
or you can build a bypass harness to bypass the lock cylinder.
you can get or build a bypass module that would make the ECM think the VATS system is working, but you would also have to bypass the starter relay.
you can have the VATS removed from the chip by burning a new chip with VATS disabled, again you would also have to bypass the starter relay.
if you do decide to replace the lock cylinder, be certain to buy a Delco lock
cylinder. the aftermarket lock cylinders are trouble prone and won't last like they should. where i used to work at, we tried the aftermarket cylinders a few times and always had to replace them within a few months with Delco lock cylinders and keys.
2 good pages of VATS info and trouble shooting,
https://www.thirdgen.org/vats
https://www.thirdgen.org/vats_passkey_system
Thread
Thread Starter
Forum
Replies
Last Post
Gunner242
Electronics
7
12-25-2015 04:49 PM
