Thread: What is TBI?

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I did one of those free VIN number checks online and heres what came up...

Year: 1992
Make: Chevrolet
Model: Caprice
Style/Body: 4 Door Sedan
Engine: 5.0L V8 TBI
Country of Assembly: United States

My question is this, what the hell is TBI in the "Engine: 5.0L V8 TBI " thing.

What does it mean and or represent?

Throttle Body Injection. It's basicly a fuel injected carburator. Your engine is a 305 TBI.

GnuVince
Throtle Body Injection.
It's one of GM's early atemps at fuel injection, It has in youre case two injectors directly above the throtle blades. There is also an I.A.C (idle air control) motor and a T.P.S (throtle position sensor) conected to the throtle shaft. I think the TBI is a verry dependible unit, but it wont in stock form deliver enough air into the system if u do any major motor mods.
I hope this helps U out.

Thanks for correctin me Streets, I have always considered it injection cause that's what I have always heard it called. Is it technicly fuel injection? Or is it fuel induction.

damn, somebody's CRABBY!

Originally posted by Streets
TBI=Throttle Body INDUCTION! IT injects nothing at all, the piston going down in the cylinder with the intake valve in the open position SUCKS the fuel mixture into it Peroid...

Clip taken from Automotive Technology - A Systems Approach Written by Jack Erjavec and Robert Scharff

Throttle Body Fuel Injection

For many auto manufacturers, throttle body injection (TBI) served as a stepping stone from carburetors to more advanced port fuel injection systems. TBI units were use on many engine during the 1980's and are still used on some engines. The throttle body unit is similar in size and shape to the carburetor, and like a carburetor, mount on the intake manifold. Fuel supply and return line service one or sometimes two fuel injectors. The injector(s) spary fuel down into a throttle body chamber leading to the intake manifold. The air/fuel mixture in the manifold feeds all cylinders.

Look's like Streets isn't the smart one anymore is he?

I dunno, i think streets still knows more.

Originally posted by Streets
.. IT'S SUCKED INTO THE CYLINDER BY THE PISTON GOING DOWN WHILE THE INTAKE VALVE IS OPEN..
'nother iggy ..

Streets true... To add-if we take into account that for every action there is an equal and opposite reaction, hence vacuum-- nature's abhorrence to fill a void.

Excuse / I digress--We had an individual in our shop that many claimed " could pull a 27" vacuum on an onion sack." .. sorry

If you want to be technical about it...

The vacuum in the engine doesn't "suck" anything. It creates a low pressure area and atmoshpheric pressure "pushes" the air and fuel in...

Unless you have a supercharger, then your "suck" turns to "blow" and the price goes up

yeah, what mad sez. and what Streets sez. Hope nobody is taking what they read in some rag mag as gospel.....

So agreeing on terminology does matter????

Ah.............life's little pageant!!

Want to know what my whole theory on TBI is?"Does it work? Yes. Good, then dont worry about it"

Originally posted by Streets
Gee excuse me mr know it all. IT IS ONLY INJECTED INTO THE MANIFOLD!!! So what gets injected into the cylinder?? NOTHING at all.. IT'S SUCKED INTO THE CYLINDER BY THE PISTON GOING DOWN WHILE THE INTAKE VALVE IS OPEN..
'nother iggy ..

Calm down, don't have a heart attack.... I was being sarcastic so I hope there's no worries?

drg84 I do not dout you're oppinion, on streets. I most always agree with what he types. In the automotive field today I deel with Fuel Injection every day. That is how I was tought, and that is how the industry describes it.
Travis