Topic: TBFI Install
in Forum: Non-Vette Automotive Discussion
Already a Member?
Click Here to Login
Not yet a Member?
Click Here to Register for Free!
Swapping out the Q-Jet carb on "BLKBRRD" and replacing it with a TBFI unit. I feel I can do the physical/mechanical stuff with out any problems but I'm not the best with doing electrical stuff. Need to find a keyed power supply for the fuel pump system and the TBFI unit. The instructions that came with the unit are rather vague on exactly where to find power so I need some direction. Would what I'm looking for be somewhere under the hood or do I need to punch through the firewall to locate something under the dash?
Jim Olson 
"The Toys"...!!! Save the Wave! 
SPONSOR AD:: (Our Sponsors help support C3VR)
I would think that the "hot" wire going to the distributor would work.
Lifetime MemberBelvidere, IL - USA
Joined: 10/24/2004
Posts: 439
Vette(s): 1977 Black T-Top ZZ4 5Sp 16in Wheels
Jim, I ran mine to the Ignition at fuse block. Thinking about adding an electric disconnect.
Gold MemberEast Peoria, IL - USA
Joined: 9/29/2005
Posts: 15
Vette(s): 1975 Bright Blue T-Top
I installed an Edelbrock throttle body EFI and ran mine to the fuse block IGN.
OK - Electronics 101 question(s):
Bill - "hot wire" to the distributor? I guess without a picture or more words I'm clueless.
Dick/Ron - fuse/ignition block... under the dash or under the hood?
I can figure out where most of the other wires go from the wiring schematic in the instructions but the keyed power source baffles me. 
One wire is supposed to go to the temperature sending unit. Can I splice into the wire that goes to the gauge?
Jim Olson "The Toys"...!!! Save the Wave!
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
You do NOT want to tie into the ignition feed at the distributor.
|UPDATED|4/4/2019 7:10:34 PM (AZT)|/UPDATED|
You need to connect to a terminal in the fuse box under the dash. You will prolly see at least a couple blade type terminals marked "IGN". You can use a male, blade type connector on the wire from the TBFI unit.
Yes...you can "tee/splice" into the temp sender wire...usually a green wire at the sensor.
|UPDATED|4/4/2019 7:10:34 PM (AZT)|/UPDATED|
Joel Adams
C3VR Lifetime Member #56 
My Link 
(click for Texas-sized view!) NCRS
"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
Joel - MANGE TUSEN TAKK....!!! (Norsk for MANY THOUSAND THANKS...!!!) 
That's exactly what I needed to know. Now I just need to figure out where to go through the firewall. Pretty sure I can find a grommet to fish a wire through. In fact, I may need to make one as I want to bring the control pad for the ECM inside the car.
Thanks for the guidance!
Jim Olson "The Toys"...!!! Save the Wave!
For my new electric choke, I used the old tan wire that went to the anti-dieseling solenoid on the carb. It's key on 12 volts. Don't know if a 78 Trans Am has that.
To the best of my knowledge/recollection there isn't anything electrical on this Q-Jet (haven't pulled the Shaker Scoop and air cleaner off yet). Mechanical choke, mechanical secondaries, etc. I'll most likely end up drilling a hole in the firewall to pass wiring through as I want to bring the controller for the TBFI unit into the car and mount it somewhere on the dash. I highly doubt there is an existing passage that would have the room for more wiring.
Thanks everyone!
Jim Olson "The Toys"...!!! Save the Wave!
Almost there...!!!
Drilled a 1/2 inch hole in the firewall next to where the accelerator cable comes through, stuffed in a rubber grommet and have passed wires/cables through. Joel, the fuse block under the dash looks VERY different from the picture you posted so I'm digging through the manuals I have to find an electrical system schematic to see which circuit is "keyed".
And as directed by the FI-Tech kids I cannot splice into their temperature sending unit wires so in order to have the dash gauge AND the ECM work both temperature sending units need to be used. After some more research I found that with the TB EFI I don't need all the EFE and EGR stuff so I pulled the thermo vacuum switch from the intake manifold and reused it. 75%, no - make that 90%, of the vacuum tubing on this beast is related to the emissions stuff so as soon as I can find a block-off plate I'll pull off all the EGR hardware and tubing to clean up the appearance.
So not much left to do. Route and connect 4 wires, mount the hand-held controller somewhere near the dash and connect its cables, prime the fuel pump canister and then set the initial parameters with the hand-held controller. Turn the key and watch the mushroom cloud...!!! 
btw - there was nothing electrical on the Q-Jet. All mechanical and vacuum.
Jim Olson "The Toys"...!!! Save the Wave!
in Forum: Non-Vette Automotive Discussion
SPONSOR AD: (Our Sponsors help support C3VR)