Because of tbi throttle cable being unavailable I am thinking of just doing a tpi conversion. I have found a couple of 90's tpi units off cars that are being parted out. I have emailed about price for all the parts. Is there anything I need to watch out for or anything that I will have to rewire or will the engine harness cover it all. Will there be any problems or changes to the harness at the computer.
Also what has been the standard time frame for doing this comversion as I will need the car running asap.
All help with this is greatly appriciated.

 

Lol, you're gonna swap to TPI simply because you can't find a throttle cable? I thought I was nuts

It's a pretty straightforward swap, off the top of my head you'll need the intake setup, wiring harness, injectors, and you'll have to swap to a TPI fuel pump. I would recommend mocking everything up first though, before you tear down the TBI engine. Just loosely bolt together the intake, plenum, and runners, and make sure all the sensors, and their plugs are there. It will be much easier to figure out what parts you're missing that way.

There are a few differences between years for TPI too, that you may wanna watch out for:
- 85-87 has v-belts, mass airflow
- 88-89 has serpentine mass airflow
- 90-92 is serpentine speed density
I would try and get the 90-92 setup if possible, MAF sensors are expensive.

 

Feeling the amount of resistance that it there now and not knowing how long it has been this way since I just bought the car, I figure it is just a matter of time before it breaks and leaves me stranded somewhere.
Besides I really wanted Tpi anyway. More hp,better throttle response and more efficient than Tbi. By the time I spent all the time and money to get the Tbi system up to standards I would be close to the conversion anyway.

 

I am doing this also. Is the used MAF-sensor from donor not cheap to get included or is this just a reminder? Does it wear out or does it has to be replaced often? I've read that GM went back to maf in 94.

The VATS, can i get it to work easy? Last car got stolen.

I want to shift to 6-speed later, have automatic now. Does the tpi need to be for automatic to work or will I have to wait for the transmission?

If I have a 91 tbi, does it have a serpentine and do I then have to go for the 88+ models?

Is the heads on a 305 tpi different from a tbi?

Anything else?

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91 firebird 305tbi, flowmaster 3" catback

 

Also, trot over to www.chevythunder.com. Lots of info on their site.