MPFI

[Turnerjcaleb411]

Does MPFI add more HP? How do you tell your truck has it, besides tearing it apart.
97 k1500 5.7 vortec


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[slowburb]

Will not add any more HP than the truck had when it was built. You have to tear it apart to tell.

 

[Biggershaft96]

Like he said, your not gaining amything over stock. Pretty sure you can pull the tb off and see.

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As you can see the mpfi lines are huge compared to the poppet style and there are wires on each line.

 

[grampadirt]

Not sure you can tell without removing the upper intake manifold.I see you found my picture /\ I did the upgrade on my wife's '99 burb over six years ago because I had to,the CFI control module stopped working.Immediately upon startup it ran smoother and after driving it there was better throttle response.After driving it a while we noticed a slight increase in mpg's as well.I used the Delphi unit and to this day is running great(over 200,000 miles now).

 

[Turnerjcaleb411]

Is it a necessary upgrade?


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[Biggershaft96]

Not sure you can tell without removing the upper intake manifold.I see you found my picture /\ I did the upgrade on my wife's '99 burb over six years ago because I had to,the CFI control module stopped working.Immediately upon startup it ran smoother and after driving it there was better throttle response.After driving it a while we noticed a slight increase in mpg's as well.I used the Delphi unit and to this day is running great(over 200,000 miles now).

I didnt know that was yours lol. I just yanked a good pic off google to show the difference.

Is it a necessary upgrade?


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If the stock unit starts leaking fuel this is the fix. Until you have a reason to change it, i would leave it alone.

 

[grampadirt]

I didnt know that was yours lol. I just yanked a good pic off google to show the difference.

Hey no prob,glad to see it could help someone

 

[superdave]

You can open up the throttle blade and look right down the throttle body to see which one you have. The poppet version has small tubes

 

[Tachyon]

You can tell if you have it by the beefier fuel regulator. Though its hard to tell the difference without an old CSFI unit to compare to.
It's hard to say if it adds horsepower in and of itself though it's certainly possible due to a more precise injection pulse that would keep the engine in an optimum AFR range more of the time, but it absolutely does improve throttle response and fuel economy. I'm also pretty sure that it will allow larger horsepower gains in combination with other mods like a programmed ECU, improved breathing (air intake, headers, exhaust system, etc.)
The MPFI upgrade is the most recent mod I've made to my truck and I wish I'd done it first. It's not a simple job, but it's worth it IMO.
BTW, both Rock Auto and Amazon have good prices on the genuine MPFI spider if you watch for a sale.

As for being necessary or not, no, but the CSFI unit WILL eventually fail and most likely it will fail slowly, trashing your fuel economy, making the truck run rougher and rougher, and gumming up your engine with sludge before it does fail.