351W questions
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Fleet Mechanic
Joined: Mar 2009
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From: Sacramento Delta, CA
351W questions
I have no answers only questions.
My 1995 Bronco has the 351W with MAP and is OBD and is Multiport Fuel Injection.
The 1996 351W is MAF and OBDII and is Sequential Fuel Injection.
What is the difference between MFI and SFI?
And why are you choosing the former?
If I have to put a remanufactured 7.3LPSD in the van, everybody is recommending Jasper Engines.
@rla2005
@subford
@Conanski
@Kemicalburns
My 1995 Bronco has the 351W with MAP and is OBD and is Multiport Fuel Injection.
The 1996 351W is MAF and OBDII and is Sequential Fuel Injection.
What is the difference between MFI and SFI?
And why are you choosing the former?
If I have to put a remanufactured 7.3LPSD in the van, everybody is recommending Jasper Engines.
@rla2005
@subford
@Conanski
@Kemicalburns
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
$1800 is a good deal... if they used quality parts in it. These engines are simple so they really should not cost too much.
MPI describes the intake style and all of these EFI motors use the same type. The 5.8 motor for example used the same intake from beginning to end through all the EFI control system changes.
SFI MAF and SD/MAP describe the EFI control system, the first type is Sequential Injection with Mass Air flow sensor, second type is Speed Density/Manifold Absolute Pressure with batch fuel injection.
The first generation OBD1 system came in both flavors but the second gen OBD2 version was only offered in SFI MAF.
MPI describes the intake style and all of these EFI motors use the same type. The 5.8 motor for example used the same intake from beginning to end through all the EFI control system changes.
SFI MAF and SD/MAP describe the EFI control system, the first type is Sequential Injection with Mass Air flow sensor, second type is Speed Density/Manifold Absolute Pressure with batch fuel injection.
The first generation OBD1 system came in both flavors but the second gen OBD2 version was only offered in SFI MAF.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
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From: Kentucky
MFI is Multiport Fuel Injection meaning each cylinder has it's own fuel injector. They are fired in batches. SFI is Sequential Fuel Injection which also means each cylinder has it's own fuel injector and each one is fired individually to coincide with the spark plug firing order.
1994 and up 5.8L engine blocks are roller lifter ready and by mid 1995 most did come with a roller cam. They are very common these days and a good platform to start with. There is nothing that makes an engine OBD-I or OBD-II, it's how the computer system is designed and operates. While there is one year specific external parts on the 5L and 5.8L engine that make them unique for the 1996 model year/OBD-II, EGR feedback and misfire sensor assembly, the long block/heads are the same as the larger Federal emission trucks that stayed OBD-I.
Fleet Owner
Joined: Oct 2005
Posts: 20,789
Likes: 1,753
From: Kentucky
In theory Mass Air Flow/Sequential fuel injection is more efficient than Speed Density/ Batch fired injection therefore there may be a slightly better MPG gain. The change to MAF was based on emissions not necessarily MPGs.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
MAF is capable of better performance but despite the more accurate sequential injection scheme it usually does not return better gas milage as the MAP system tends to be tuned for leaner overall operation.
That said I believe the common Mustang PCMs used in conversion kits had a lean burn strategy that came into play on extended highway cruises, I know my MAF converted truck was capable of exceptionally good highway cruise fuel milage.. 20mpg with the 5.0 and almost 18mpg with the 5.8.
That said I believe the common Mustang PCMs used in conversion kits had a lean burn strategy that came into play on extended highway cruises, I know my MAF converted truck was capable of exceptionally good highway cruise fuel milage.. 20mpg with the 5.0 and almost 18mpg with the 5.8.
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