Hi, so I have this nice 91 I bought minus the engine and trans. I have an 89 350 TPI setup I am going to put into my 91. But I am trying to convert the wiring from the dash, to the computer, its a different style connection, I was wondering has anyone done a swap similar to this?

Would you know the wires that I have to splice together? I don't have extra connectors for this stuff, so I have to solder the wires together and get it set up, any help would be appreciated.

After I have this motor in the car, I'll rebuild my 87 iroc-z trans, missing 3-4 clutch pack, then put it in the car, and use this as my daily driver for next summer. Thanks for the hep guys.

 

https://www.thirdgen.org/forums/tech...formation.html


What engine the 91 had when it left the factory would help

 

The 91 formula was a 305 tbi car, and came on the title as a formula, just a 91. I'm mostly building this into a quick street car, but eventually a full on 10 point cage race car, but I have another one built for the drags already. I just wanted to make this 91 a sweet TPI 350 car and turbo it later on. I just have to put a 9 bolt posi in it, and build my other trans for this one for now.

 

So what you are doing is a TBI to TPI (MAF ) swap

Do you have the complete TPI engine bay harness ? ( and computer )

 

Yeah I have the whole 89 harness, computer, all relays and MAF, and the harness is perfect un tampered with, and since the TBI cars don't use much as far as relays or anything, I can mount the brackets on the firewall, and just weld them up to it, to complete the look just like a factory TPI MAF car would, I like MAF systems better, it has the 91 nose on it now, with a 88 GTA hood, and an 89 whale tail spoiler on the hatch, just the front seats, the dash is on a sled in my shed, once I figured out how to wire the 91 dash to the 89 computer through that one connection, that I believe is just for the gauges and dash, I want to set it up and put it in the car, then put the doors back on and put it in.

 

The dash operates independent of the computer so the wires for the dash sensors on the engine should be the same colors

What you need is the circuit diagrams for both years so you can see what wires go where on the firewall connector so you can correctly connect them, the earlier TPI may use different pin locations than the TBI did

This may be of help
http://berlinetta.info/C100.htm

 

Well so the gauge wires from two different connectors I can just splice together based on there colors?

the gauge setup I have for the 91 formula is the same as my gauge set for my 89, identical, and this 91 gauge set I don't think came in a v6 firebird, I believe it was the tpi v8 also, so I think they maybe the same, I'm gonna try to put it in the car today, its just hard to do by myself

 

It would be much easier to just repin the stock harness to a Speed Density TPI since its speed density already. You then just have to adapt the injector harnesses.

 

This car was a 305 TBI, and I have all the necessary stuff to make it a maf car, and I plan on turboing this car, so I prefer maf rather than MAP, I checked out the connectors today, they look like I should be able to swap it together fairly easily, theres some small things that may be missing but I have to wait till I put it in the car to see what else I need, I have a lot of steering parts for the column, and I know what the vats value is, so its just a matter of putting it together at this point.

 

I looked around a bit and I can't find another 89 dash right now, so I have to make what I have work, Its just gonna take time, but until I get it in the car, I can't compare all the wiring. The dash is in my shed, and the car is next to the house, so its kinda difficult lol

 

Well I have the dash installed, its a 92firebird dash with the 120mph speedo, but I think thats correct for that year tbiformula anyway. I just have to put the fuse block in position, but I have to pull the dash back off to put the top two screws in. Then I have to put the engine harness in and figure out what I need to do on both of those bulk heads, but also converting that dash wiring to my 89 harnesss, connectors are totally different.

 

What year berlinetta is that C100 connector for? My dash is actually from a 92 firebird, with the 120mph speedo, theres some pieces I need to find, but I wanna see if I can get it set up to run the motor, and hopefully, its maybe a lock module, or windows or something. Theres some connectors on the passenger side, two diff ones, that go into something, then I will have to hard wire the stuff to the airbag sensor on the trans tunnel, I just don't have the connector. Then I'm gonna try to figure this wiring out and get it set up.

So UPDATE, has anyone reading this post gone from a 92 dash for a firebird, I believe tbi car, to a 89 TPI MAF harness and computer? Theres still two connections that the 89 has 13 wires and I think the 92 has 14 wires, I'm not sure quite what its for, maybe the computer communicates with the dash through it. I could use some help there

 

The link has the C100 connector diagrams for 82 -92 so you can compare the differences between different years

 

Yeah that part looks easy, the harder part is getting the 92 dash wiring to the 89 computer wiring, I'm not quite sure what it is, but thats my next thing to figure out then it'll be ready, I just have to set up that motor and gonna be nice to do.

 

Theres a guy named Pocket on here, I guess he has done some of this kinda work before, anyone talked to him before? Maybe he can help me