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'85 K5 w/ 454 Carbed, wanting to convert...

454k5blazer

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Wanting to convert my fuel system and have been thinking about going to EFI. Is it more reliable? Is the gas mileage worth it? Is there any better options out there?
 

1-ton

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The increase in fuel mileage may not be worth it, unless you do a whole lot of driving in your K5. The main benefit from fuel injection is during wheeling. Carbs have a tenancy to shut off on steep inclines while fuel injection systems will not.
 

diesel4me

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A few guys I know with later 454's in 1990's and newer trucks (one is a dually ) say their trucks only get around 8-12 mpg despite being EFI..

So I agree if mpg is your main goal,a swap to fuel injection isn't worth it--what it will do is make for easier cold starts and no hesitation or stalls cold like a carb would on choke,and there is no chance of flooding like a carb due to no floats or needle valve to get stuck open..

I think a few years of the early fuel injected 454's had a throttle body that bolted right up to a Q-jet intake...a used factory setup from a salvage yard would be much less than an aftermarket one..
 

454k5blazer

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A few guys I know with later 454's in 1990's and newer trucks (one is a dually ) say their trucks only get around 8-12 mpg despite being EFI..

So I agree if mpg is your main goal,a swap to fuel injection isn't worth it--what it will do is make for easier cold starts and no hesitation or stalls cold like a carb would on choke,and there is no chance of flooding like a carb due to no floats or needle valve to get stuck open..

I think a few years of the early fuel injected 454's had a throttle body that bolted right up to a Q-jet intake...a used factory setup from a salvage yard would be much less than an aftermarket one..
Yeah gas mileage isn’t a main concern more so for reliability, such as the cold starts. Is it a pretty simple swap?
 

Bent77

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Yeah gas mileage isn’t a main concern more so for reliability, such as the cold starts. Is it a pretty simple swap?
Not bad

Talk to @folkenheath
He’s our resident guru and can answer lots of your questions
 

folkenheath

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It won't necessary be more reliable, but it will be more consistent with weather, altitude, temperature, throttle response, etc. Easier to drive and maintain.

You can swap it a few different ways, factory TBI is only about 15 psi, most aftermarket EFI are 40-60 psi that have better fuel atomization. These can be swapped on without swapping intakes depending on your intake manifold.

The best benefit is with sequential multiport, which requires swapping intakes, however, you get better performance with swapping intakes anyway, especially since TB injection in some instances doesn't have good distribution with dual plane intakes, it varies with application.

Either way, the two other parts are upgrading your fuel system for 40-60 psi instead of 6 psi, and adding an oxygen sensor in your exhaust, most systems come with them but any leaks throw it off, so it the 02 bung should be welded in the exhaust tube.

The best way to put EFI fuel pump in a blazer is to get a TBI tank from an 87-91 blazer and then swap a walbro pump into it. But some people just put an inline pump back by the tank.
 
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