Im in the process of switching over to tpi, but all the info Im getting on the subject says I have to get a chip with vats removed.My VATS works now with my TBI, cant I get the value of the key(resistor) and have it programed in the TPI chip?Do certain ECMs go with certain VATS moduals? Any help would be greatly appreciated.

 

The ECM does none of the PassKey proccessing. Thats the job of the PassKey module. All the ECM sees is the "fuel enable" signal from the PassKey module. The key resistance and stuff all go to the PassKey module. If you are converting to TPI, you will need to retain all of the stock PassKey components, and run the Dark Blue wire to the new ECM. I don't know which system (MAF or Speed Density) you are using, so I can't tell you wich wire, but if you are using MAF, only one year ('89) had PassKey, so you will need an '89 chip.

I did this on my '87 using a computer and chip from a '92 and everything looks stock even though it wasn't offered in these cars untill '89 (I even put the "security" lens in place of the old "choke" lens, so even the light in the dash works. It will be very easy for you since its already setup in your car, its just a matter of making sure the Dark Blue "fuel enable" signal is installed to the new ECM and the right chip is used.

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If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

GM Tech I am putting in a speed density type TPI. My car is a 91RS and all the passkey components function right now.The ecm I am going to use is the 730 one for the TPI.If you could give me any tips on keeping it functional that would be greatly appreciated.While were on the subject,is there any thing else that will change for tpi such as speed buffer ect.. Ive read all the posts and tech articles and they dont seem to mention several thing that I know are different for TPI cars such as the speed sensor , esc and fan operation. If you could clear up some of this stuff since you have done it, that would be great. thanks again

 

You will just need to run that "fuel enable" wire to the new ECM. As for the speed buffer, on the 1227730 ECM, the buffer is internal, so you can ditch the external buffer the TBI uses. Before I give you any more advice, what type of wiring harness are you going to use?

------------------
If you live in Southeastern US, check us out!
South East Thirdgen


ASE Master Tech + L1
Savannah, GA

'87 Trans Am
S/D TPI retrofit including functional PassKey,
22# injectors,
Whatever chip I feel like burning,
JET AFPR, Ported Plenum,
TB Coolant Bypass, Custom Cold Air,
SSM SFC, KYB Shocks, Boxed LCAs, Wonder Bar,
8mm Accel wires,
Flowmaster Exhaust,
16" GTA rims,
Corvette Servo,
-->14.97 @ 94.9 MPH<--

'97 Bonneville SSE

 

GM Tech, I will probably use a harness from Street and Performance or GM if they can order it.Ive heard alot aftermarket harnesses are incomplete or setup for street rod applications so Im being selective about which one I will go with. I have just about everything else I need for the swap except for the harness fuel pump and chip for the ecm.I want a harness with full emmissions and all.Any suggestions? thanks for your help

 

i'm putting in a 89 MAF TPI into my 91 TBI Firebird.will i have any problems with the VATs system?

 

91banditt2: The '89 harness will already have the dark blue VATS wire in it, so you shouldn't have any problems.