4.0 with 87 MAP system

[GDRBO]

Can an 87 MAP system support a 4.0 motor swap. Yes, I know it is not the best choice but we do have that system complete. We are missing many parts as well as the wiring for the MAF system. So to refresh can it be made to run?

 

[RonD]

It would be an effort.
4.0l never had a distributor, early engines had the EDIS-6 module which can run as a standalone system.
You will need to feed the signal from the EDIS-6 to the '87 PCM for injector timing, it normally got that from the sensor in the distributor.
And the '87 was a batch fire injection system, so 3 injectors open at the same time, and they just alternate, so timing of injectors isn't that critical, but without a timing pulse they won't open at all.

Going thru the list of sensors the '87 PCM would use seems OK, nothing jumps out at me.

MAP only system does need the Air Temp sensor, you may need to add that to the 4.0l, MAF combines the two.
I am just guess but the 4.0l injectors should add the correct fuel mix with the pulse from the '87 PCM.
I am assuming the 4.0l injectors are larger than the 2.9l injectors.

 

[GDRBO]

The 2.9 distributor seems to fit the 4.0 block. There is a drive (shaft?) to drive the oil pump from the cam in the place of the distributor. The distributor should still trigger the injectors as well as the spark plugs. The injectors do have different part numbers for 2.9, 3.0 and 4.0. Any clues for a source as well as placement of the Air Temp. sensor?

 

[RonD]

This thread shows pictures of the 4.0l oil pump gear next to a 2.9l distributor base, they do look exactly the same:
http://www.therangerstation.com/forums/showthread.php?t=16444

So it might work
There was some speculation that the lower intake on the 4.0l would be in the way for distributor mounting.

Air temp sensor is usually on the upper intake and MAF(also air temp) is on the air cleaner, so I guess the easiest place to install it would be on the plastic air plenum, closer to the intake would be best.

Very good site here with info on Ford EFI system and sensors
http://oldfuelinjection.com/?p=1

This page is worth reading as well
http://oldfuelinjection.com/?p=4

 

[GDRBO]

Just a follow up, the 2.9 distributor does NOT clear our 4.0 Areostar intake manifold. We don't have any others to try, so that road ends here.

 

[adsm08]

You need to get a MAF system to make a 4.0 run properly. A speed/density system can only handle so much increase in displacement, and 1.1L is too much for the 2.9 system. You won't get it to run right on a 2.9 computer.