Does anyone know what components are different in the newer 89 MAF system compared to the earlier 86 design. I know the cold start injector is eliminated but aside from the runners, fuel rail and manifold did anything else change? Did the plenum stay the same? How about any of the sensors?

 

All of the sensors stayed the same, about the only change (other than the CSI removal) was in the brand of injectors used, VATS and the "code" for the bin files on the prom ($32, $32B, $6E etc.)

 

I do know for a fact that the computer is different in 86. i went over this one time when i put my 87 tpi in. as far as sensors go, i'm not totally sure.

 

All ECM's for TPI were the same from 1986-1989, they all used the 165 ECM. 1985 was the odd ball ECM, it used the 870 and was the only year it was used.

 

so the sensors are interchangeable and other than a new BIN the computer is fine, but will an 86 plenum match up with 89 runners?

 

Yes, sensors will interchange but you may have trouble mating the plenum to runners, be sure to get gaskets for the 89.
Also the 86 intake will not directly bolt on to the 89 heads and the 89 manifold won't bolt right onto the 86 and older heads, there is a difference in the angle on the center intake manifold bolt holes but this can be "corrected" with some machining.