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

 

if you are swapping engines, whats the big deal to remove and swap a harness, seems like a trivial amnt of work after pulling an engine.

but, ya, youll have to swap harness's

 

The speedo isn't controlled by the computer. It's hooked the VSS(speed sensor). The TBI car's is too.

 

if you were really picky you wouldnt really have to swap the harness either, just do some repinning and add a couple leads to it on the engine side. There is one slight difference with the VSS.. cant quite remember though and it may not affect the MAF tpi setup since it might have been the same. Just look at a wiring diagram sometime

Dont forget youll also need to change the fuel pump (dont worry about the lines) and throttle cable. Its not that much work once you know what you are supposed to do.