1991_RS

We're in the process of swapping a 350 TPI from a 1991 Z28 into a 1989 Formula Firebird that had a 305 TBI.

We have the entire motor harness and computer. Comparing the accessory wiring on the motor harnesses, we're noticing some big differences. I know that the 'Bird has the battery and charcoal can reversed for the 350. But we're also seeing some bigger problems - the brake emergency light is on the accessory harness on the driver's side of the 'bird, but there's also one on the Z28 motor harness. Also, we're not seeing the wiper and washer plugs on the new harness (on the motor harness of the 'Bird) The list could probably go on and on.

Is the problem with the harness due to the different years, going from a 'Bird to Z28, or both?

Spent all day pulling the 305 and I really need to get this project out of my shop this weekend!!! Any First Hand knowledge would be greatly appreciated!

Atilla the Fun

You'll have to get schematics, and modify the new harness.

Tuned Performance

iTrader: (92)

user insomniac just did the same conversion

TORN

iTrader: (17)

https://www.thirdgen.org/forums/tpi/...d-density.html

Or repin the TBI wire harness.

1991_RS

Thanks Torn, but we looked at that earlier and it seems to be dealing with the collection of plugs that go directly into the computer - is that correct?

We have the original TPI computer AND harness, but the plug on the driver's side firewall is pinned different. We spent 2 hours chasing wires around and made our own diagram, but there are a couple big differences (besides the locations of the wires):
The TPI has 2 black/white wires that are grounded to the block (TBI has none)
The Alternator wires on the TBI go through some sort of relays and the ECM (The TPI only goes to the firewall plug)

Does anyone have a diagram for repinning the plug on the driver's side firewall (or did I miss it in the post)?

jedrom

iTrader: (1)

Hey guys, I don't mean to be posting in the wrong place or anything but I don't think I can start a new thread because I'm new, but this is the thread that seemed to pertain most to my predicament. I am looking at purchasing an 89 camaro that doesn't currently run because the current owners have come to a halt on their overhaul. Stock the car came with the 305, and they decided to swap it out with a 350 from a 92 camaro. Since then they have not been able to quite figure out the electrical and what has to be done in order for it to be run as a tpi. The rest of the car is in great shape and even the tranny has recently been rebuilt. My dad is quite car savvy so depending on how difficult it would be to get her running and the cost, it could be worth it for me. Thanks for any advice, I'll try to get on later to try and answer any questions.

jedrom

iTrader: (1)

Too maybe give you a better idea of what is going on, the owner said that the engine will turn over, and also start up and pop with a little shot of ether, but he can't get the injectors to pulsate.

jedrom

iTrader: (1)

Also the 350 is out of a 92 camaro.

Tuned Performance

iTrader: (92)

jedrom you need to start your own post and not hijack threads. Check power to the ecm and ecm grounds. if you have spark and 12v to the injectors more than likely this is a vats issue.

jedrom

iTrader: (1)

Sorry about that, I just figured out that I could start a new thread. I'm a member on a couple of other message boards and they require a minimum of 25 posts before you can start a thread, I thought that might also be the case here. Here's the link to my new thread if you think you can offer any more advice: https://www.thirdgen.org/forums/engi...c-z-305-a.html.