I have a 1987 GTA 5.7 that was totaled. I bought the car back,it still ran good. I have located a 1989 TBI Firebird with a bad engine for a very reasonable price. My question is how much work is needed to convert a TBI car over to a TPI car? My greatest concerns are with the wiring harness and computer. Do I have to completely remove the TBI engine wiring harness and computer and replace it with my 1987 TPI harness and computer? Do I have to completely remove the wiring harness for the gauges since the speedometer is controlled by the computer?

I have all the parts from the 1987 GTA, I just want to get an idea on how much work I am looking at.

Thanks

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

Since you have the donar car, it should be relatively easy. Yes, you will have to change the ECM harness, but the under dash wiring should be the same.

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Bob '89 Ram Air Formula 350
Last(lost)Member of the Elusive Great Lakes Crew
My car's homepage

 

Having the donor car makes it lots easier. You can swap the entire drive line over and swap fuel tanks also. Don't get me wrong, it's a lot of physical work. Sounds like a good project.

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Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/relocated MAT/ AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

Thanks,
I was wondering what actually controls the speedometer and gauges, the ECM for the engine or some other system? The donar car has the digital dash setup, do I have have to switch the TBI cars under dash wiring to make the gauges work with the 1987 GTA computer?

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29