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Location: Hellfire and Brimstone!...A.K.A. portland
Posts: 323
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Car: 91' TRANS AM Modified
Engine: Classified
Transmission: Auto with Overdrive
Re: Community effort - defeating VATS sticky
Originally Posted by Tuned Performance
@tibo what year is that I don’t recognize the colors of the enable relay wires.
I did the bypass on my 91, but started to have intermittent stall outs, the car would run for about 20 minutes then stall out, some times even the fuel pump would shut off, then last week the alternator fried out, I did swap it for a new one, but not sure of the car will make it long distance to anywhere right now?...any advice having to do with VATS will be very helpful*
Location: Hellfire and Brimstone!...A.K.A. portland
Posts: 323
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91' TRANS AM Modified
Engine: Classified
Transmission: Auto with Overdrive
Re: Tech: How to bypass VATS
Originally Posted by Aviator857
If you are keeping the pasakey module with your engine swap make sure to ground the module through the c207 connector. Pin m on my car but it will be the black/white wire. Looking on the 92 schematic above it grounds through the c100 connector.
If the module is working you will get the security light for a second or two when you first move the key to run position, then it will go off. If you have the right key or resistor in place when you move it to start the starter relay will be grounded and starter will engage. If you have the wrong key the security light will come on and disable the starter for 10-15 min or so.
I did the bypass on my 91, but started to have intermittent stall outs, the car would run for about 20 minutes then stall out, some times even the fuel pump would shut off, then last week the alternator fried out, I did swap it for a new one, but not sure of the car will make it long distance to anywhere right now?...any advice having to do with VATS will be very helpful*
My understanding is that the VATs system is for start up only, once the engine is running it is out of the loop. I'd guess, maybe, you have a bad ground situation somewhere, losing power and the alternator was seeing very low resistance, alternators don't like running without the correct loading.
The alternator regulates voltage and doesn't care what is the electrical load but it does care about load dumps. As you well mention, if there is loose/broken wire somewhere that is causing inductive devices to cycle on/off, then it can cause large voltage spikes and some of that energy will be consumed by the diodes in the alternator. Do it repeatedly in a short amount of time and the diodes will overheat and fail... and alternator dead.
Shelton, maybe it's worthwhile to step back to the beginning and explain why you did a VATS bypass in the first place? What were the symptoms of the problem you were trying to solve.
Yes it can be grounded anywhere you have a common ground, all you are doing is providing the passkey module a new ground since it was lost when the connector/ecu sub harness is removed.
Hi I recently bought a 92 Camaro RS with no key. I bought a new key switch and I have been trying a few days with resistors to get it started but with no success so far! The car has the ECM and Passkey module. I tried option C (Jumper the starter relay plug with a wire) and the engine cranks.
If I leave it like that will I have issues? If I understood correct the VATS also cuts off power to the injectors or does this method C power up the injectors also?
No, you have to get an ECM chip burned to delete VATS to pulse the injectors or get a VATS emulator to trick the ECM to think it is still getting the VATS signal.
Hallo,
I bought a new key and ignition cilinder. The after-market key does not have the same resistance as the old one. So i need to bypas the VATS as well.
I have chosen for method C. But my injectors do not fire. Do i need to ground these to?
Ground what ? If your still efi the passkey needs to send a hz signal to the ecm. Get a hz modulator, new computer chip or correct resistor on the bottom of the column to the passkey module.
Hallo,
I bought a new key and ignition cilinder. The after-market key does not have the same resistance as the old one. So i need to bypas the VATS as well.
I have chosen for method C. But my injectors do not fire. Do i need to ground these to?
Thank you in advance!
is your car ls swapped? If so you need a bypass module still or tune VATS out of the PCM. If stock EFI get a bypass module so the ECU sees the vats as working. Though easier is take your old key and your new key to a Chevy dealership and have them cut a new key with the right resistance and the right cut.
Hallo,
I bought a new key and ignition cilinder. The after-market key does not have the same resistance as the old one. So i need to bypas the VATS as well.
I have chosen for method C. But my injectors do not fire. Do i need to ground these to?
Thank you in advance!
The best thing to do is watch a bunch of videos on YouTube of how VATS works so you get and idea what to do.Once you kind of understand how it works you have a few options. 1.Try to find what the resistance of the VATS module of your car is by trying the resistors method.
2. Buy a Eprom with the VATS deleted and don't have to worry about it again.
I went with option 2 and am very happy!
3. There are a few more options which a never tried. You can find on Third gen if you search.
Good luck.
HUH?!?! Not even remotely in the same ball park as an illegal activity of rolling back the odometer.
It is a basic, common, and necessary modification for people that upgrade or change engine management system. And it is probably in the top 3 questions asked in this particular forum.
I just want to say a few things since this older thread had recent postings, and because to want to clarify a few things based on the opinions of a former GM Engineer/ P.E.D. -Delphi Engineer.
First things first... This was a perfectly put together Thread by QwkTrip.
It really is great, with all the pertinent and correct information.
By now, I am not surprised because I regularly find Threads and Posts by QwkTrip to be done quite well.
This is information that I feel all VATS equipped 3rd-Gen owners should know... or at least have access to.
The VAT-Systems of this era were problematic... and depending on what has failed (intermittently or not)...
Bypassing may be the ONLY choice in order to start/ run the vehicle.
These systems were also extremely basic... There are many reasons why modern-day VAT-Systems are far more complicated.
The information posted here (in a very nicely broken-down/ categorized manor) goes over different steps/ methods of Bypassing VATS.
All this information was taught to GM Field Engineers and Technicians that needed to be able to Bypass, Diagnose, and Repair VATS.
So there is no harm done by the vehicle owners also learning this information.
I want to emphasize that there is nothing "crooked or criminal" about this information...
What is "criminal", is an individuals intention to use this information for illegal purposes.
I really feel that this was a great, informative, and well put together Thread that deserves praise and should not be questioned in terms of morality.
Learning to Drive an automobile is not a criminal act... deciding to run-over a person in order to do them harm is a criminal act!
Don't miss the distinction!
Great Job QwkTrip!!!
Last edited by vorteciroc; 05-15-2021 at 10:00 PM.
Thank you for the advice. I would like to use a resistor as well. But there is no key with the resistance and the VATS does not accept any of the 15 resistors. I found a document that claim to know how to relearn your VATS, But i still need to test this.
My 17 year old son and I are trying to resurrect an '89 Camaro 305. It runs well when it runs, but has a hard time starting. After lots of research, we have figured out that we don't have the original key with the resistor. We bought a bypass module, but it doesn't seem to help.
As far as we know, it has the Original ECM, although it appears to likely have been messed with by a previous owner.
From the OP, it looks like the best option might be to replace the ECM with a new one that eliminates the injector control and use "Method C" from above to bypass the VATS Module and Starter Relay.
Does this sound like the best option? Or is there a better option like replacing VATS module?
If replacing the ECM is the best option, can you recommend a source for the replacement ECM? Please provide a link if possible.
Thanks in advance.
Adding this info to the thread regarding 88 GTAs, as suggested by @QwkTrip. While all F-Bodies got the VATS in 89 as known, it was throwing me off that my 88 GTA had VATS, while no other model from 88 got it. And most 88 GTA owners I conversed with said they didn't have the VATS. Not to mention my VATS ignition cylinder wire is a different color (black with yellow, instead of the standard orange with white). Now it turns out even the starter enable relay isn't located in the standard location behind the kick panel. As it turns out, GM decided to phase in the VATS in the model year 88 GTA ONLY, and not the other Firebird models (I don't know if they did something similar with Camaros). And in 88, it was ONLY the GTAs made from December 1987 onwards that got the VATS. Consequently, everything related to the VATS is slightly different relative to the 1989 models onwards, such as wire colors, relay locations etc. I received this information from the very knowledgeable administrator of The Trans Am GTA Source Page. I've attached the GM document detailing what I just stated above. Hope this helps any 88 GTA owner who has the misfortune to have a GTA made from Dec 87 onwards and equipped with VATS
, like me.
I have bypassed the ignition component with a resistor and I’m certain that works but I still get intermittent security light no starts. I have stock ecm.
Is this a sign my vats module is nearing end of life? The security light comes on and stays on and then two or three (4 minute delayed) tries later it will usually start just fine.
I tested with an old key that never worked and it will usually start fine with the bypass.
maybe dumb q but: Do I need to replace the stock ecm to bypass the starter relay as in option b above?
I am assuming if the ecm is not getting a consistent hz signal from the pass key module then bypassing the starter relay would get me crank but no fuel as the stock ecm won’t engage the fuel injector without a signal from the pass key module…?
or can I bypass the stock ecm control over the fuel injector?
Thank you. This does not sound particularly difficult. I will try it and let you know.
(I am not a mechanic this is the first car I am learning to work on, if you think I’m likely to wreck something trying to do this as a novice please let me know.)
would you recommend upgrading the ECM while I’m at it or is that not worth the effort? I’m having fun with my son with it, squeezing everything we can out of the RS :-)
would you recommend upgrading the ECM while I’m at it or is that not worth the effort? I’m having fun with my son with it, squeezing everything we can out of the RS :-)
I recently bought this for my 1990Camaro RS 305 car. My cars keys were lost. I changed the ignition switch and NOW I find out I have a VATS issue. I never knew of this until I got this car. After to talking to some people they suggested I get that vats module . The unit did not come with directions. I had to go to my computer to look up some video. (very annoying when you shop is a bit away from your home computer) The video shows -with power to it, how it works. It does not show installation. Then I see theirs another place to look up how to install ( In my opinion total BS!, it should come with directions!. Anyway ,It explains to use this wire to this pin and that wire to that pin etc. Well My 90 camaro does not match any of that text. These are for some other car apparently. So now I have this useless $25 thing and a car I cant fire up! I`ve about had it with all this VATS crap. I`ve been into older cars for almost 40 years. Built hot rods , had many great OLDER cars. This is my 1st car newer than 1977 and its been a terrible experience so far. Too much BS under the hood and beyond!
If someone can provide me a schematic of my pcm plugs that has the known wires to connect this tiny box to that would be great. Basically its the White wire I believe and a black for ground and a red for power or switched power. I have more time into this than it would take me to change out head gaskets on a v8 ! Very frustrating.
thanks
If this doesn’t work and the new chip from tunes performance doesn’t work for whatever reason I’ve got a third option which is software flash to
the chip.
I do have confidence that we can defeat this stupid system 😂
This is the 89-92 tbi pinout. Accessory power pin A6. Cut passkey hz signal wire and hook device signal to pin B6 and then any ground. It needs a 30hz signal I don’t think the 50hz works only for later years.
This is the 89-92 tbi pinout. Accessory power pin A6. Cut passkey hz signal wire and hook device signal to pin B6 and then any ground. It needs a 30hz signal I don’t think the 50hz works only for later years.
Than you very much for this diagram! I just came out to do it & it’s just my luck the B6 color on my harness is blue. Not purple as stated. Should I assume the blue is correct? Also do I hook the white wire to the plug end after cutting the wire? Or the harness end? I’m new at this pcm game. Thanks! A pic of my A1-B1 plug . This is the B side
The color is probably blue , cut and hook white there ecm side of cut wire.
from the instructions:
RED: 12V ignition of accessories
WHITE: Fuel Enable wire. 50hz or 30hz.
BLUE/GREEN: Control wire. If none of the wires connected to the ground then the output is 50 Hz
suitable for most of the cars. Some cars (90-93) require 30 Hz. In that case, connect the Blue wire to
the Ground.
BLACK: Ground
Ok, I did hook the white wire up to the blue wire & the red and black as needed. The unit flashes as it should. Went to start & nothing. So I then took the blue wire & connected it to ground for the 30 setting and it flashed differently as it should. Went to start and nothing. I need to walk away. I have too much time into this POS. I appreciate & thank you for all the help. I’m just done for now. You may see it up for sale or on a trip to the scrap yard.
thanks!
12-29-2018, 11:09 PM
HUH?!?! Not even remotely in the same ball park as an illegal activity of rolling back the odometer.
