I have a quick, probably dumb question.. I actually have a 1992 Chevy van with TBI and saw a video on youtube that had the same van with a TPI conversion. In the video, it showed the van running and running well, but also, the injectors were "jumpered" off of the ORIGINAL TBI injector connectors. After studying a bunch of wiring diagrams, I can't see why I couldn't do the same thing.. It doesn't look like each individual injector gets it's own signal.. It looks as though each bank of injectors is fired at alternately. I fully understand the idea "if it were that friggin easy", I'm not expecting to be able to just "slap it on and go".. I've also read about modifying TBI harnesses. So i am guessing the main reason for a TPI computer and harness is strictly pin-outs and programing? you have to have the TPI programming and for that, you need a specific ECM? which in turn requires changing pins on the harness. Correct? or am I dreaming and misreading everything?

OK.. thanks for any info.. as this will become my winter project.

 

Your right in the statement about the TPI firing all 4 injectors on each side as a BANK. I really don't get why in the world they would do this and would like some one that has some insight to this to explain it. Makes just as much sense to me as the fact that my Camaro (1991 Z28 5.7) has one O2 sensor and it is on the drivers exhaust side. IOW, isolated from the exhaust flow from the passenger side. Seem frigin goofy to me.

 

With the exception of the '89 TTA, ALL 3rd gen f-body port injection systems are BATCH fire. As being batch fire all 6 or 8 injectors fire at the same time.

The '89 TTA is SFI.

As for running a TPI setup with a TBI ECM it is possible. Although there are drawbacks and pit-falls.

RBob.