V8Rumble

iTrader: (9)

Hey all,

I guess that the subject line pretty much says it all - I'm really wanting to do an LQ4 or LQ9 swap in my car (and have been busy gathering as much info as I can), but if there's any way at all, I'd like to retain the VATS function. My car is a 1989 Trans Am GTA.

I'm guessing that I'd likely have to swap in the steering column from a compatible F-car, but does anyone know if that would work with the LQ-series ECM? What other parts/info would I need?

Thanks guys.

slow

iTrader: (7)

The best solution would be to use a BCM out of a 4th gen car and wire it to your existing steering column, use the PWM output of the BCM to the pcm, you will need to alter the VATS from serial to PWM on that pcm

Then you will need to get keys that match what is the resistance in the 4th gen pcm. (or you can use resistors inline to increase the resistance of your key, to the bcm stored resistance, if the stored resistance is higher than your keys already)


Ryan

Brains

iTrader: (7)

You'll need a BCM -- Body Control Module. This is the unit that reads the resistance value of the key, and if it matches the value stored in its permanent memory, it will send the signal to the PCM to pass the VATS test. There's two "types" of fuel enable signal to the PCM, Camaro/Firebird/etc. use a PWM waveform on a dedicated wire, while most other vehicles get the signal on the Class 2 data bus. Most tuning software will allow you to set which method the PCM expects (PWM, Class 2, or NONE) and this allows you to match the type of BCM you install.

LS1Nomad

V8Rumble:

Baker Electronix makes a VATS bypass module that you can wire into your harness. You can either wire it in to bypass the VATS completely, or wire it thru a plug that would enable you to keep the VATS active until you plug in the module for security purposes. They're available on EBay. -Rick

RE AND CHERYL

iTrader: (31)

Is your 89 TA originally equipted with VATTS? I know they were in some of the 3rd gen cars. If so you will need to find out where the control for the system is located. In the 4th gen cars it's in the BCM. I think the earlier cars had a VATTS control module.

Problem is the newer cars adn trucks don't use VATTS. The keys have some type or transmitter in them that sends signal to an antenna near the column. Not sure if you would be able to make that system work in your vehicle.

Re'

V8Rumble

iTrader: (9)

Thanks guys, I really appreciate it.

I'm guessing that the BCM module would involve three wires - PWR, ground, & the signal output wire - is that correct?

Also, since I'll be trying for a pretty late-model 6.0 or 6.2, I'm guessing that whichever output method I choose (PWM or Class 2) would have to be the same as what's used on the vehicle that the donor engine & PCM came from, right?

LS1Nomad, that sounds like it might just be a neat little "end-run" around the issue, I'm definitely going to check that out!

Re', my GTA does indeed have VATS, but AFAIK, it's all contained within the PCM. I can check my factory shop manual though.

If worse comes to worst, I suppose that I can just go with the LoJack system, but I'd REALLY prefer the VATS+LoJack...

Thanks again guys.

V8Rumble

iTrader: (9)

Thought I'd try again to see if anyone had an answer to my questions above...

Thanks again guys.

G-Body

iTrader: (4)

I`m not really sure about the BCM, I have not really seen anyone use one unless they were using the entire harness out of the latemodel car and trying to keep all of the interior electronics.

I think that it would require at least the power, ground, signal, and 2 wires from the key sensor. But I don`t know if it would work at that point because the BCM would notice that there are a lot of things it wasn`t connected to (IE door pin switches, radio, speedo, and all the other sensors that it normally monitors.) I don`t know if the BCM could function with everything else missing, if it could be reprogrammed to run that way or if it would just sit there and refuse to do anything.

You can change the setting in the 6.0l/6.2l PCM so that it would accept the pwm, or serial data signal so you could use a BCM that provides either signal. It may be easier though to build a electronic box that would recognize if the resistor in the key was the correct value and if it was provide a pwm signal to the computer and then just change the PCM to accept a pwm signal.

70 LS1

iTrader: (1)

Reprogram the PCM like G-Body said to accept the non serial signal and make a VATS simulator box that is removable. Mine is about the size of a Zippo, is completely hidden, and is quickly removable so I can slip it into my pocket. That way I don't have to mess with the whole BCM and key thing.

Don't mind the connector, I quickly swapped it for a much smaller one.

V8Rumble

iTrader: (9)

Man, that is very cool. Hope you don't mind if I send you a PM asking for more details...

RE AND CHERYL

iTrader: (31)

I think I got what you are looking for. The earlier OBD I cars did not use a BCM but did have VATTS. Check out this electrical diagram HERE.

You would need a Theft Deterrent module and key or VATTs code from a 93-95 car. It's way easier than a BCM to install and would get you what you want.

I think what 70LS1 has is a bypass module that has to be plugged in for the car to run.

Re'

70 LS1

iTrader: (1)

The OBD1 cars use a 30Hz signal while the LS1 uses the 50Hz signal. Even using the parts that Re' mentioned, you would need a frequency multiplier to get it right.

I guess technically I am using a VATS bypass module, but I never thought of it that way. Basically I am using a 5V 50Hz signal generator that will sent the appropriate Fuel Enable signal to the PCM. Its pretty simple and has only 3 wires, ignition hot, ground and signal.

RE AND CHERYL

iTrader: (31)

The Earlier F-body VATTs was simpler. It didn't even go through the PCM. Just interupted the ground to the fuel pump relay.

If you really want it, I'd just delete the VATTs in the PCM and install the Theft Deterrent module. It would be a simpler system that would be easy to set up.

Re'