Thinking about a 4.9 Mass Air Flow Swap

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94f150rules
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Thinking about a 4.9 Mass Air Flow Swap

Post #1 by 94f150rules » Tue Jul 10, 2018 12:06 pm

Im taking my truck apart this weekend and doing a cam swap, along with a new oil pan since mine rotted out, Im installing the Crane 503901 Cam, and eventually a new exhaust. From what everyone says the Speed Density system pretty much prevents you from getting any real gains, and Id like to get all I can from the engine. Ive been trying to find someone who actually did the MAF swap and most people just ask but never do it. First I found out California got MAF late 94 early 95, these would be OBD 1 computers are they still sequential or would they work with my batch fire wiring harness. If thats the case I could just add the pins to the harness.... I bought the Ford Wiring and vacuum manual, and Im still getting to know how my 94 F150 is wired but, it looks like the engine harness is only connected to the ECM. If its anything like the 2.3 Turbo I swapped in to my Mustang 2 It just needs ignition power, keep alive power, a connection to the fuel pump relay, and some assorted grounds.Im thinking that some of the connections that would be hard to get to or something I could just cut and solder into my new harness. So is the swap to a 96 harness that difficult? I found one in the junkyard for $250, and Im pretty sure finding the ECM wouldn't be too hard. There is a few parts Im not sure about, do I need a different upper manifold?, Is the rubber hose that goes from the throttle body to the MAF still available new?

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bubba22349
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Re: Thinking about a 4.9 Mass Air Flow Swap

Post #2 by bubba22349 » Sat Jul 14, 2018 11:44 am

The 4.9 Mass Air systems came out in mid 1995 and were used until the end of 4.9 / 300 production in 1996 on F150's & E150's and in a few 1997 models like the F250, F350 Super Duty's (that still used the body style as the 1996), maybe the E250, E350 also. There is almost no parts interchange between the earlyier EFI system. I don't think it's all that hard to swap out the harness, but if you do the swap try and get the compleate EFI system (off that 1996) with that harness plus the computer too. Good luck on your swap :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

86f250straight6
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Re: Thinking about a 4.9 Mass Air Flow Swap

Post #3 by 86f250straight6 » Sat Jul 14, 2018 11:39 pm

MAF engines are a totally different animal than an SD.

- The exhaust manifolds are different as there is an O2 sensor in each manifold that is part of the injector harness
- MAF also has a crank position sensor with a tone wheel behind the harmonic balancer you would need as well (MAF eec iv needs cam and crank sensors for sequential injection)
- The IAT sensor is no longer mounted in the intake like SD, it is mounted in the airbox. not a big deal but youll either have to extend the wires or move the sensor.
- The egr is different also, it uses a pressure sensor to detect egr flow which has 2 small metal lines running to it from the egr pipe. Since your engine doesnt have youll either have to swap it over or do some tuning since the computer will be looking for it and not be happy. It takes alot more to delete egr with MAF than on SD,

Im sure there more that im forgetting, but the best thing is to have both engines side by side and switch things around as needed. Obd2 is alot more sensitive to missing sensors than obd1
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arse_sidewards
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Re: Thinking about a 4.9 Mass Air Flow Swap

Post #4 by arse_sidewards » Mon Jul 16, 2018 8:02 am

There were TWO different MAF systems. There's the 95ish MAF system used in Commeifornia, Assachusetts and any other state that had a "we only sell Commifornia emissions vehicles 'round these parts" law in 1995 (none that I am aware of). Then in 1996 the OBD2 capable EEC-V system was used. If you want to modify stuff then seek out the latter. EEC-V has much more aftermarket support than EEC-IV just because of age. I personally wouldn't use either, I'd use Megasquirt/Microsquirt or one of the many aftermarket EFIs (that are all designed to be tuned by the end user, unlike EEC-anything) that are available for sale at present.

If you want to swap on a stock MAF system you should certainly get the entire harness from the donor truck. It will make your life much easier. I'd get the manifolds too but don't sweat it if you don't since you can easily add fittings for sensors to the Y-pipe.
1994 F150 4x4 8ft, engine is basically stock.

66" leafs, extended radius arms, lockers in both ends, nothing special.

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MechRick
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Re: Thinking about a 4.9 Mass Air Flow Swap

Post #5 by MechRick » Thu Jul 19, 2018 4:30 pm

^^^^^^^ This.

The problem with the stock EFI is the size of the injector (14 lb-hr). A stock MAF system will fix the low manifold vacuum at idle problem created by the cam, but will not address the injector size.

I have a reasonably complete '96 EFI/MAF system in a box somewhere. It's a much more complex harness that incorporates the under hood fuse box. It would be easier to pin out a SEFI computer and add the extra circuits, and even easier to switch to a Megasquirt with some junkyard 24 lb-hr injectors.
1994 F150, 4.9L/ZF 5 speed, C-Vic police driveshaft
EFI head w/mild port work, 3 angle valve job
1996 long block, stock pistons, ARP rod bolts
Stock cam, aluminum cam gear
Hedman header, full mandrel bent duals, crossover, super turbos
http://fordsix.com/forum/viewtopic.php?f=2&t=73244
Bronco II with a 2.3L swap http://fordsix.com/forum/viewtopic.php?f=13&t=72863
1988 F250 2x4, 460 ZF 5 speed.

arse_sidewards
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Re: Thinking about a 4.9 Mass Air Flow Swap

Post #6 by arse_sidewards » Thu Jul 19, 2018 7:22 pm

MechRick wrote:^^^^^^^ This.

The problem with the stock EFI is the size of the injector (14 lb-hr). A stock MAF system will fix the low manifold vacuum at idle problem created by the cam, but will not address the injector size.

I have a reasonably complete '96 EFI/MAF system in a box somewhere. It's a much more complex harness that incorporates the under hood fuse box. It would be easier to pin out a SEFI computer and add the extra circuits, and even easier to switch to a Megasquirt with some junkyard 24 lb-hr injectors.


If you want to be ghetto you can run two MAFs, (one on each throttle body tube), only plug one in and run 24lb/hr injector. Engine gets 2x the air and about 2x the fuel the computer thinks it's getting. Is it kind of hack, yes. Will it run pretty ok, yes.
1994 F150 4x4 8ft, engine is basically stock.

66" leafs, extended radius arms, lockers in both ends, nothing special.

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