TBFI Install - Forums - Official C3 Vette Registry

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Burke, VT - USA

Vette(s):
SOLD - "The Toy" - '70 Convertible
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Still have - "BLKBRRD" - '78 Pontiac Trans Am

Joined: 1/23/2002
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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?

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Jim Olson

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Re: TBFI Install (2/13)
4/3/19 7:09pm

BillHanna
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Cana, VA - USA

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1975 Stingray 71 350 engine Flat top pistons Sniper fuel injection Hyperspark ignition Vintage Air air conditioning Borgeson power steering box

Joined: 7/3/2016
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I would think that the "hot" wire going to the distributor would work.

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Re: TBFI Install (3/13)
4/4/19 11:24am

VetteCountry

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Belvidere, IL - USA

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1977 Black T-Top ZZ4 5Sp 16in Wheels

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Jim, I ran mine to the Ignition at fuse block. Thinking about adding an electric disconnect.

Re: TBFI Install (4/13)
4/4/19 1:26pm

Techdocwriter

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East Peoria, IL - USA

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1975 Bright Blue T-Top

Joined: 9/29/2005
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I installed an Edelbrock throttle body EFI and ran mine to the fuse block IGN.

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Re: TBFI Install (5/13)
4/4/19 4:43pm

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. Confused

One wire is supposed to go to the temperature sending unit. Can I splice into the wire that goes to the gauge?

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Jim Olson

"The Toys"...!!! Save the Wave!

Re: TBFI Install (6/13)
4/4/19 6:10pm

Adams' Apple

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Duncanville, TX - USA

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#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

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You do NOT want to tie into the ignition feed at the distributor.

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|

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Re: TBFI Install (7/13)
4/4/19 8:14pm

Joel - MANGE TUSEN TAKK....!!! (Norsk for MANY THOUSAND THANKS...!!!) Thumbs Up

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!

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Jim Olson

"The Toys"...!!! Save the Wave!

Re: TBFI Install (8/13)
4/5/19 10:10am

F4Gary

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Grapevine, TX - USA

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1972 LT-1 convertible with factory air. 2017 Black Rose Grand Sport convertible.

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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.

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Re: TBFI Install (9/13)
4/5/19 1:01pm

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! Thumbs Up

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Jim Olson

"The Toys"...!!! Save the Wave!

Re: TBFI Install (10/13)
4/25/19 6:59am

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...!!! LOL

btw - there was nothing electrical on the Q-Jet. All mechanical and vacuum.

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Jim Olson

"The Toys"...!!! Save the Wave!

Re: TBFI Install (11/13)
4/25/19 9:23am

Adams' Apple

Norsky said: 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".

Regardless of cosmetics, you will find at least 1 or 2 empty terminals in your fusebox that are marked "IGN". Doesn't matter if it uses glass fuses, or other types. Thumbs Up

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Re: TBFI Install (12/13)
5/2/19 9:49pm

There was only 1 open spade connection in the fuse box and only 1 labeled IGN - which had a pink/black wire connected to it. So I pulled the pink/black wire off the IGN spade, made a two spade pigtail, connected it to the IGN spade, connected the pink/black wire to one side of the pigtail and the white wire to the TB-ECM to the other side of the pigtail. IT WORKED...!!!

Also made a two spade pigtail to connect to the TACH connector on the HEI distributor. Then connected the stock connector to one side of the pigtail and connected the blue wire to the TB-ECM to the other side of the pigtail. IT ALSO WORKED...!!!

With "key on", but not cranking, followed the instructions for using the handheld controller to set the base parameters. Then a few 10 second cranking sessions primed the fuel canister. Connected the fuel pump power wire, turned the key to crank again and the engine started right up.

It idles very smoothly and there's no "cold engine" hesitation. The pedal action is a little stiffer and it has a little less travel than the Q-Jet. Getting in motion the engine feels stronger and it pulled hard until I let off when the speedo needle buried itself...!!! Being gentle on the pedal works fine but stomping on it causes it to stumble. Talked with a tech rep and he gave me a setup parameter to play with so have a little "adjusting" to do.

Over all I'm very HAPPY...!!! "BLKBRRD" hasn't "flown" this well ever.

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Jim Olson

"The Toys"...!!! Save the Wave!

Re: TBFI Install (13/13)
5/3/19 3:14am

Adams' Apple

😎

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