efi and pfi cadillac engines
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Forum Description: Got a technical question about your fiero? ask it here.
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Topic: efi and pfi cadillac engines
Posted By: gtexotic
Subject: efi and pfi cadillac engines
Date Posted: 07 January 2009 at 6:22pm
| I am looking to buy a cadillac engine for my fiero and I was just wondering what exactly is the difference between the two. I have my eye on a 1992 cadillac fleetwood and im not sure if its efi or pfi. Any info would be great thanks |
Replies:
Posted By: Romeo
Date Posted: 07 January 2009 at 7:44pm
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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. |
Posted By: Patrick
Date Posted: 07 January 2009 at 11:21pm
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Speak for yourself young fella. When I was a kid it was MFI. (Figure it out. |
Romeo wrote:
)Posted By: Romeo
Date Posted: 07 January 2009 at 11:48pm
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Multi-Port, I'm assuming? ------------- Never shift into reverse without a back-up plan. |
Posted By: Dr.Fiero
Date Posted: 08 January 2009 at 6:58am
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PFI is Port Fuel Injection. It's a hybrid of MPFI (whats on a Fiero) and TBI (throttle body injection). It uses individual injectors at each cylinder, yet uses a 'dry' throttle body (looks much like a carb, but flows air only, no fuel). EFI simply refers to electronic fuel injection, regardless of technology (TBI, MPFI, TPI, PFI.... etc). |
Posted By: gtexotic
Date Posted: 08 January 2009 at 11:48am
| So the pfi engine is not anymore powerful than just the standard 4.9 just more efficient? |
Posted By: Dr.Fiero
Date Posted: 08 January 2009 at 12:05pm
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AFAIK, they were all PFI. Some had one, or two O2 sensors, that seemed to make a difference power wise. The Alante (sp?) had a better intake. Dave has done more research on this note, so I'll pass the torch to him. |
Posted By: Capt Fiero
Date Posted: 08 January 2009 at 12:39pm
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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. |
Posted By: Romeo
Date Posted: 08 January 2009 at 3:03pm
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I thought the Fiero used Batch Fire Fuel Injection, also known as wet carb... Hm... ------------- Never shift into reverse without a back-up plan. |
Posted By: Dr.Fiero
Date Posted: 08 January 2009 at 3:52pm
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). |
Posted By: Patrick
Date Posted: 08 January 2009 at 5:23pm
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No sir, you're not going back nearly far enough.
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Posted By: Dr.Fiero
Date Posted: 08 January 2009 at 6:16pm
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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.... |
Posted By: Patrick
Date Posted: 08 January 2009 at 6:23pm
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Ding, ding, ding... we've got a winner! (Great picture by the way.)
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Posted By: Romeo
Date Posted: 08 January 2009 at 8:40pm
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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. |
Posted By: Patrick
Date Posted: 08 January 2009 at 10:10pm
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Careful now, it's not like I date back to the age of steam. What's this thread about again... John's truck?
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Posted By: marcelvdgn
Date Posted: 08 January 2009 at 11:05pm
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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 |
Posted By: marcelvdgn
Date Posted: 08 January 2009 at 11:07pm
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I may have a 4.9 avail from a 99 deville ill be checking it out on monday if anyone interested ....let me know ------------- Marcel 86SE V6 Auto 85SE V6 Auto 85 2m4 soon to be sleeper 3.8sc 5 speed |
Posted By: Dr.Fiero
Date Posted: 09 January 2009 at 8:06am
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4.9? You sure? Or is it a N*? |
Posted By: Capt Fiero
Date Posted: 09 January 2009 at 9:34am
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93 was the crossover year, some cars got the 4.9 and some got the 4.6 after 93 All caddy's were 4.6 Northstar. The Northstar is a far Superior engine, however at 10x the work and cost to install it. There are more economical choices out there. ------------- Capt Fiero 88 Fiero GT 5spd V6 Eight Fifty Seven GT V8 5spd. |
Posted By: marcelvdgn
Date Posted: 11 January 2009 at 1:29am
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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 |