Need more info on tbi to carb swap

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Jan 2, 2006 | 05:13 AM
  #1  
Before anyone says anything, I have searched, but need clarity. I have an 88 Iroc with tbi(I know, its weird), and i was thinking of converting but I am a little fuzzy on the fuel pump situation. It is my understanding that the tbi uses something like a 12lb pump.

-If I wanted to use that pump with a regulator, what would I need assuming that the car is no longer computer controlled what-so-ever?

-How is the fuel pump turned on and does it pump at the constant 12ish or so lbs?

-Could I just hook a regulator to it, put the fuel to the carb, and turn the key with it firing up, or would I need a swith to turn the pump on?

Its not a performance bound car, so I would like to use the stock in-tank pump. The whole tbi setup is shot from the unit, to the ecm, so carb is all im considering and I want to see if its worth fixing. Thanks in advance.
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Jan 2, 2006 | 01:56 PM
  #2  
If you are keeping it stock and it doesn't make any power then you can get away with the stock lines and in tank pump.

Use a Mallory 4309 return style regulator. You will also need a non CC vacuum advance distributor. I suggest using an MSD distributor with a 6A box. It's the easiest to setup and wire. Pick a carb and intake of your choice.

The pump supplies a constant 12v. to the pump through a relay on the firewall that is activated by the ignition. You'll want to re-wire it since it runs off of wiring that's inside the factory engine harness.


Remove the factory engine harness, TBI, ECM. Plumb the lines and regulator, intstall the intake/carb/dist. Run wires from the factory senders for the gauges to under the dash on the pass. side and get a pinout of the plug to see where they go. This will let you keep your factory gauges.
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Jan 3, 2006 | 03:51 AM
  #3  
Quote:
Originally posted by Dialed_In
The pump supplies a constant 12v. to the pump through a relay on the firewall that is activated by the ignition. You'll want to re-wire it since it runs off of wiring that's inside the factory engine harness.
This is mainly what I need info on because I want to make sure that the setup will be reliable as a daily car. I would like to know which relay it is because my relays are mismatched between stock and a 91 rs which is what the drivetrain came out of, due to the car being a big pile with nothing functional when I got it. Also, would it be advisable to use the stock relay, and what should I wire it to, a switch?
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Jan 3, 2006 | 06:40 PM
  #4  
You will be removing the factory harness and thus, the factory relay with it.

Either way you do it, you'll need a relay. You can wire in a toggle switch to operate the relay, or you can run it to a keyed +12v and the ignition will now take the place of the circuit. I would hook it to the ignition, it's the same amount of work either way.
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