I bought my 1988 Pontiac Firebird with the 5.0L TBI about a year ago. I have just begun to become interested in swapping the TBI unit for TPI so if anyone knows: what parts I will need to do this, how much it will cost, how much work it is, how long it would take, if I should even bother doing it or has themselves, or had a friend swap the TBI to a TPI I'd be interested in learning what is involved. Thanks.

 

By far the easiest way to swap from TBI to TPI is to use the Street and Performance Integrator harness. Plug and play for the most part. Plug your stock ECM connections into thier box, the new box plugs into a 1227730 ECU and has a new harness coming out of it. Leave your original harness in the car and use it to read most of the sensors, the new harness adds all the required connections. If your uncomfortable with alot of splicing and repinning I would suggest you look into this. The only drawback is the price. It's expensive...
-Mike

 

I've accumulated a bunch of stuff so far:

TBI wiring harness

1227730 ECM (found in most any 3.1L Corsica, Beretta, Sunbird, etc.) With pigtails.

Memcal for the ECM

TPI Unit (runners, upper/lower manifolds, etc)

Air Cleaner Assy (still working this one out)

Injectors (for a 305 I would use a 3800 series I injector from 88-90 model year, rated @ 19 lbs)

Fuel Pump

Fuel Filter

Gasket set

 

How difficult was it to find all those parts? Do you think I would be able to get most of them at a local GM Pick and Pull? Also, is that all that you will need or is there anything else? and finally how much time/money have you spent on it so far. As far as the wiring goes, what exactly do I need to do? Do I just use some sort of connector that you guys were talking about or do I have to rewire the harness or anything like that?

 

https://www.thirdgen.org/techbb2/sho...hreadid=216453

Get a hold of the pinouts form both the tbi and tpi cars from www.diy-efi.org/gmecm and you'll understand what all those number/letter combos mean.

The 3800 Seroes I engines are probably 40% of a GM section in any given pick-n-pull. The 1227730 ecm is in any given 3.1L corsica/beretta/sunfire. You need the right memcal though, which runs about 65 bucks from gmpartsdirect.com

I bought the TPI setup on the classified board on this site. Between school and work I took the better part of the past 6 months gathering, cleaning and powdercoating and reading up on the swap. I think I'm ready to tackle it this weekend... I'm going to get it to run on my Firebird's 305, then transplant the whole setup onto my 350 I'm building.

some parts you're probably better off buying new, like the knock sensor and appropriate speedometer sender, but the pick-n-pull has a lot of the other sensors you may or may not need.

Perhaps a person in your position might want to consider the Holley TBI unit and boring your intake manifold to 3" holes. I did this on our pick-up truck and it Hauls azz. It's begging for an exhaust. I cna help out with either swap as best I can.