I currently have an 89 LO3 RS with TBI and I want to convert to TPI with Speed Density (TPI for look and dryness, Speed Density for higher HP capability) from a 91-92 Camaro. Here is the main problem. I have VATS and I want to keep it. I also know everything I need for the conversion, I decided to get a TBI-->TPI harness adapter so I don't have to pull my harness from my car, my biggest concern is the ECM. I know I need the one from the doner, or a brand new one of the same number. What should I do to keep the VATS capability? What are my options? Thanks for the help!

 

As long as your car is already VATS capable And you are putting the ECM from the donor car in yours there should not be any problem with it. The code for your key is stored in the VATS control module which is a separate unit from the ECM.

The Trickster!!!!!!!!!!!!

 

Sorry if I'm off topic, but can you give me a list of all the parts you've got for the conversion?

And where are you getting the adapter harness? What exactly is it? Thanks

-Rippin

 

Here are 2 links i am using for my conversion, neither are complete really, both have a parts list and a general how-to, seems neither did a follow up after the installation.

<https://www.thirdgen.org/newdesign/tech/tbitotpi.shtml>
<http://sethirdgen.org/tpi1.htm>

I used these because I'm going from MAF to SD. If you choose MAF it will be slightly different for you. As for the harness I decided to send my harness to Speartech <www.speartech.com> to rewire my current harness, seems to be a little cheaper.

Trickster, I want to make sure I am understanding this correctly. All years that have the VATS ECM already have every code saved into the ECM? So I can use a new or old ECM from a speed density VATS car and it will know to read my key? Get back to me, thanks for the explanation!

 

That is correct N/A91CamaroRS,

The codes are stored in the VATS control module, not the ECM. There is only one code stored in the VATS control module and that is the one in your key. That is why you can swap out the ECM from different cars of the same year and model.
The ECM only has a command line in the memcal telling it to look for a response from the VATS control module and respond accordingly.

The Trickster!!!!!!!!!

 

Excellent! Thanks!