efi and pfi cadillac engines

Well, I can't comment on what PFI is, unless it's port fuel injection. EFI simply stands for Electronic Fuel Injection, and essentially it means there's a few factors that affect the Air/Fuel ratio, such as throttle, air temperature, RPM, etc... Essentially, EFI is the Fuel Injection you grew up on! lol

Never shift into reverse without a back-up plan.

Multi-Port, I'm assuming?

Never shift into reverse without a back-up plan.

So the pfi engine is not anymore powerful than just the standard 4.9 just more efficient?

Ok short answer. PFI is a type of EFI. EFI is just the blanket for all fuel injected cars. PFI is what type of EFI the car has.

All Caddy engines from the 4.1 - 4.9 used individual injectors, (one per cylinder) The allante motor was a 4.5 with a much better intake and would rev better, however had lower torque than the 4.9, its common practice if you can find Allante heads and Intake to swap it onto the 4.9 so you get the torque from the longer stroke and the much better intake and valve train. From what I understand its worth about 30hp on a 4.9.

The best 4.9 to get is the latest model you can find with dual O2 sensors. It has one O2 sensor for each bank of cylinders, which allows the computer greater control over which side of the engine needs more or less fuel trim. Due to that mod, "Fast Chips" was able to tweak the stock caddy motor to gain 20hp just from re-tunning the chip. From the factory GM set the motor up to be dead smooth, and produce as much torque as it could to haul around grandpa and grandma in a heavy Caddy. The re-tune moves the power band up richens the fuel curve and tweaks the timing.

Capt Fiero
88 Fiero GT 5spd V6
Eight Fifty Seven GT V8 5spd.

Romeo wrote:

I thought the Fiero used Batch Fire Fuel Injection, also known as wet carb... Hm...

The Fiero is MPFI, but happens to do batch fire (vs. Bank or Sequential injection - but that's more a programming thing than a physical layout thing).

It is a dry throttle body (the injectors are at the ports, unlike TBI which places the injectors above the throttle plates, and is thus a wet throttle body).

Patrick is referring to mechanical fuel injection.

Debuted on the '57 corvette for GM.

Now, before this thread goes EVEN FURTHER from the OP's question....

Hey, I was just trying to be nice, and not go back too far. Wouldn't want to hurt someone's ego now, would I?

Never shift into reverse without a back-up plan.

Arent you guys forgrtting the gravity fed mechnical pumped fuel injection systems such as Hilborn

Marcel

Marcel 86SE V6 Auto
85SE V6 Auto
85 2m4
soon to be sleeper 3.8sc 5 speed

4.9? You sure?

Or is it a N*?

sorry, my mistake

it is a 1990 deville with 147k

ill let u all know condition monday evening

M

Marcel 86SE V6 Auto
85SE V6 Auto
85 2m4
soon to be sleeper 3.8sc 5 speed