73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: 79shortbed on November 28, 2007, 09:08:48 pm
-
im working on a tbi conversion for my 79. Instead of swapping heads, and intake, is there a company that makes an adaptor to run a TBI unit on my square bore intake? So far i have a complete engine wiring harness and computer. Im wanting a very simple swap, i really want to stay away from all the sensors and have very little wires.
-
The problem is, the TBI won't work without the ECM and that needs the input from multiple sensors to be able to function correctly. The best way to convert an older truck to TBI would be to buy the Holley TBI kit or if you can find a good donor truck to get all the stuff. I did it to my 75 and let me tell ya....it takes a bit of work to get it all in and working nicely.
-
http://www.cfm-tech.com/catalog/tbi_to_4bbl_intake_adapter_plate_549472.htm
http://www.affordable-fuel-injection.com
http://www.yearone.com/serverfiles/part.asp?pid=TD2202&c=0&e=1&cat=F&hid=F13AU63495&trk=
http://www.tdperformance.com/pdfs/13-CarbtoTBIAdapters-2.pdf
Affordable will makes a setup that eliminated alot of the emmissions stuff, but I wouldn't say the removal is going to make a significant difference.
-
I swapped TBI into my '84, and it is VERY VERY simple. I've been doing EFI swaps for years, but even for a first timer the TBI stuff is straight forward.
To do it right, you should have an 02 sensor, a knock sensor, coolant temp sensor, and a vehicle speed sensor.
The vehicle speed sensor requires a later cluster with a VSS output - but you don't *really* need this, unless your gonna run
a late style lockup converter.
The 02 sensor just gets a bung welded into the exhaust. You don't *really* need this, unless you want the computer to correct
the air fuel ratio for you. If you don't run an 02 sensor the car will just stay in open loop.
The coolant temp sensor helps with enrichment, and effects some of spark advance.
The knock sensor, IMO is important because it will allow you to run lots of advance, but keep you out of trouble should the motor ping.
The rest of the sensors (TPS, IAC) are on the throttle body itself.
Wiring is very very simple, especially if you have the donor harness. I ran the donor harness, ran the ecm wires into the firewall (replacing the ignition box), then spliced them into the factory harness near the bulkhead (by the brake master cyl). All you need is power, some grounds, ignition, and crank.
You will however find a need for the 94 amp alternator. I took one out of the donor '87, and just swapped the pully to use with my old style vbelts.
-- Joe
-
don't forget you need the proper distributor, along with the esc module and a map sensor. egr will have to be addressed unless you have a custom chip burned to take care of it.