I just bought a 95 LT-1 and the guy I got it from said something about getting the computer sent out to get the VATS turned off. Will I need to do this. He also said that the car will not start unless I do this. I havent started to get it in yet but I wanted to make sure if i needed to get this done. I just hope i can make heads or tails of the wiring this will be my first major wiring attempt. Wish me luck. Thanks Sean

 

Sure no expert here, but I think your 92 will have a very similiar system that will work with the 95. The pulsed wave ground signal from your pass key module that's buried deep in the dash should trigger the computer to turn on the injectors on the newer engine. You'll have to really dig into the wiring diagrams to sort it out.

 

No you dont. All you have to do is get a new VATS module and replace your 92 one, it will program itself the first time you go to start it. But the easiest thing is to just have it programmed out.

 

were would I go to get a new one? or who would I send the computer to to get it programed out? thanks sean

 

Texas LT-1 I really like you site is there any plans on finishing the site? I con use the info that you don't have completed. the main thing is the electrical. I was just wondering. thanks again Sean

 

I'm going to have to say your very wrong about this one, so have you tried this and proven it works ?

 

Yes, worked perfectly fine for 6 months all mighty LT1 swapper

If you actually look at the GM Service manuals for both year cars, you'll see the module is the same. The only thing I forgot to mention is you have to rewire the plug into the module, big deal.

 

Sean - yes, one of these days I do plan on finishing the site. It's just too hard to do right now with school. Not having my car here doesn't help either because I can't take any of the photos I want and can't just step outside and look at something and put it on the site. Here in the next week or so I'm going to modify the site and change formats on it to make it easier for others to add information or ask questions. I'll post a link when I do.

 

Sorry for questioning the almighty VATS designer about the vats system which information is hidden quite well.

As far as i've known the VATS module learns the new KEYS resistance, and the output signal from the vats box is the same, otherwise you can come tell every single different vats box / column combo i've swapped with different computers that they arent allowed to function.

With that being said, you've just shown your intellect with someone simply QUESTIONING something. And the vats box shouldnt need to be changed if what your saying is true about yours working if you in fact are running the pcm without the vats being deactivated then the thirdgen vats box output is the same as the signal the LT1 pcm uses and thats why it worked, i've just never bothered to try keeping it fully in tact since the system will still kill the starter relay with the pcm disabled, and a good alarm also helps.

 

Bad mood last night. The INPUT signal to the VATS is the same, OUTPUT signal is different, thats why you need a new module. They basically used the same lock cylinder and key reader, but the output to the ECM is totally different.

 

But what it seemed like your saying is that you do not have vats programmed out of your pcm, and that you've hooked the wire that would go to the thirdgen ECM to the vats input of the 4th gen PCM and its working. Which you also say you used a new vats module to let it read, where i see the conflict is that i can take any matching column / key / vats box i've got sitting here and put it into any thirdgen i've got sitting around and it will work, the output the vats box sends to the ECM is all the same so changing the box to a new one will simply let it re learn a new key value not change the output to the pcm / ecm.

(Basically im saying it sounds like you changed the vats box for no reason since the signal should not change for its output.)

 

You are correct on the first part in that, at the time, I did not program out VATS and connect the wires as they should be connected to the new PCM.

I don't have the service manual pages here in front of me, but I was able to actually find some info about the VATS signal and its a modulated output signal. There is a difference between the 3rd gen and 4th gen signals, what it is I couldn't tell you. When you swap out the module for the new one and repin the connector, you get the correct output. This is why if you do like you mentioned, it will work in any thirdgen. If you tried doing the same thing, but putting the column and module into a 4th gen, I'd be willing to bet it wouldn't work.

However, we did it almost 5 years ago now and I've never messed with it again, so I will admit that I may be remembering parts of it incorrectly. However, I do know that each module becomes hard coded to the specific key resistance that is used the first time you start it.

In all actuality, we may have swapped the module for no reason because we ended up bypassing the entire system about 6 months after we finished the swap. But I know we spent 3 weeks trying to figure out the VATS system. We could crank the car, it got fuel, spark, all that, but would run for 2 seconds and shut off. Upon swapping out the VATS module for the new one, it fired up the very first time and ran perfectly.

 

Sounds like what your saying makes sense, seemed odd if you were saying that each different chip or ecm in a thirdgen was set to a different vats value, but if it learns the input and output both at the same time thats nice to hear. Thanks for the info.

 

Ok Guys what do I need to do You two have completely confused me now.

 

It depends on how you answer this question - do you want a functional VATS system?

No? - Have it programmed out of the ECM or get a VATS bypass module off Ebay. Or, by far the simplest method, bypass the fuel pump relay control signal and ground the relay so that when the key is in the run position, the pump is on. I ran my car this way for almost a year, but I wouldn't reccommend it. There were a number of times I wanted to turn the key on but not have the pump come on, so I'd have to pull the relay. I wired a switch in after a while and it made it easier, but I finally put it back to computer control.

Yes? - Replace your 3rd gen VATS module with a brand new one from GM and rewire the connector for the 4th gen pinout.

 

thanks you guys for the replies. I desided to get the bypass module off ebay. My car is always parked in my garage and have a very good alarm on it anyway. I finally started to look through the parts I got with the engine and I cant believe what he throw in, the corvette valve covers and alll the corvette covers, the corvette mounting bracket to move the acc. to the drivers side. One question on that bracket how do i make that work with the 92 stuff? and he also gave me a new fuel pump high pressure, New ps pump and reservor, headers minus y-pipe, computer with laptop conection and the laptop computer, new harmonic balance, corvette servo for tranny. Thats what I have come across so far. I still have 2 boxes to go through. I cant believe my luck all for 1500.00 and the engine only has 45000 miles on it. I will not need to buy to much else to get the engine in and running. I just wanted to share my good luck with all of you. Hopefully I will have it in sometime soon. The wiringing will be my hard part. I will be asking alot of questions once i get that fare. Well thanks again for your help so fare wish me luck. I guess i benifit from his miss fortune. He crashed the car this was going to go in. and for me