questions about a possible 4.0 swap

[B2Mann]

Anyone know if therell be any problems swapping a 1999 4.0 into a 1990 BII?? First thing I think of is wiring issues. Im quite sure its almost plug and play with the 4.0 from 91-94? Help would be appreciated.

 

[AllanD]

It's a bit more complicated than "plug & play"
but not be a whole lot.

you DO need to swap out the ENTIRE engine bay wiring harness

The 1990-92 Ranger harness will work best for you, presuming you
avoid further complications by using a 1990-92 4.0 Engine.

There will be some complications related to the wiring for the rear wiper
and electric rear window defogger, but nothing that makes the job impossible.

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[B2Mann]

I was thinking that I'd only have to unplug from the firewall with the 2.9 and plug the 4.0 right in + some wiring? Why would the wiring need to be different if were just doing the swap between one harness to the next?? Isnt it essentially the same vehicle?? Besides the fact that the 4.0 has a few extra sensors on the motor.

 

[BlackBII]

I was thinking that I'd only have to unplug from the firewall with the 2.9 and plug the 4.0 right in + some wiring?

That's IF you can get a 90-92 4.0, not a '99.

And you need to replace the entire engine bay harness, along with the computer.

I swapped a 90 Ranger 4.0 into a 90 BII, it was 'plug and play'...to an extent. There were still a number of things that had be custom/changed/spliced.

 

[AllanD]

I was thinking that I'd only have to unplug from the firewall with the 2.9 and plug the 4.0 right in + some wiring? Why would the wiring need to be different if were just doing the swap between one harness to the next?? Isnt it essentially the same vehicle?? Besides the fact that the 4.0 has a few extra sensors on the motor.

Are you asking or arguing?

They are NOT "the same" to that level of detail.

Power routing to various accessories (power windows, audio system rear window Wiper/defogger etc) are routed differently

They don't run through the same pins in a given connector or they run through different connectors.

Engine bay layout changes

Vehicle year changes, hell running changes within a model year can trip you up... slight differences, but any difference is a difference... and can cause a conflict.

The Explorer power routing is VERY different from Ranger/Bronco2

Consider that the 1991-92 Explorers had power mirrors, no 1989-92 Ranger did... nor did any '89-90 Bronco2.

And to get that power to the doors involved more wires, which required a different connector.... Are you getting it yet?

I was trying to steer you to the parts that are MOST similar
NONE are completely identical.

The stories you hear of "plug and play" swaps are that... stories.

there is something that the person telling the story glossed over
OR they didn't have (r removed) the affected systems on their truck and
simply ignored the differences.

Using a 1990-92 4.0 harness in an '89-90 Bronco2 will get
you VERY Close but the ranger harness lacks provisions for
the Rear window defogger/wiper that most bronc2's are equipped
with. and if you are working an '89 Bronco2 you'd have some
power feed issues to the heater blower, because there was a
running change where they insert a relay into the circuit.

And Explorer harness changes a bunch of stuff,
not impossibly so but... Frankly I don't know what
level of "complication" you are either prepared or
capable of dealing with.

details, details, details.

You don't know what is important until AFTER it bites you on the ass.

On MY swap I put a 1993 4.0 explorer engine into a 1987 Supercab
I used the 1993 Explorer engine bay wiring specifically because I wanted the "top mounted" relays and the extra fuse sockets.
I also wanted the "Active Data Link" EEC4 (1993-94 only)
and NO EGR and NO SEFI (which narrowed it further to 1993 ONLY)

It complicated the hell out of my swap, but since I am capable
of dealing with the complication...

Frankly the wiring and splicing took me three uninterrupted weeks
before I was ready to power it all up... I made ONE mistake, I left
a ground lug loose that prevented the EEC power relay from closing.

I have ONE ongoing wiring issue on the truck.
I CANNOT make the A/C WOT cutout relay function correctly

IF the relay is triggered to (momentarily) turn off the A/C
it "hangs" and the relay never drops back out to restore A/C function
(until the key is cycled to off) and yes, I've tested it with multiple
relays.

I have a jumper wire in place of the relay and the A/C works fine
and if I want the A/C off at WOT (Climbing a Hill) I have to manually
turn it off.

I'm about to attempt to tackle this issue once again...
(I've been tolerating this issue for two years)

To use that 1993 harness I had to REMOVE a whole bunch
of useless circuitry, because the 1993 Explorers were 4WABS equipped...

but it was those relays I wanted the later harness for.
Because I wanted to use the two relay sockets for my
Fog and Driving lamps, and some of the no longer used
maxifuse sockets to provide power for my audio and
communications gear

While doing all this I retrofitted "Factory"
cruise control (which I never had) to the truck and I put "Factory"
in quotes because I had to make a hybred system using some 1987
components and some 1993 components (It was real, it was "fun" but not "real fun")

what can YOU "deal with"? Frankly I have no idea
so what I recommend is based on what is easier.

But NONE of the swaps into a Bronco2 are "plug and play".

and '89-92 Ranger? with a Ranger harness? Absolutely.

But a Bronco2 is just enough different to drive
you nutz if you aren't expecting it.


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[B2Mann]

I was just asking. No arguments here. The more knowledge I have of the swap I think should prepare me a little more.

So a 99 4.0 is out of the question. (Im sure it can be done, but not for me) I want to keep it as simple as possible without too much hassle with the wiring, that why I mention the "plug and play" aspect. Im not that great with wiring, just taking things apart and putting them back together.

So I need to look for a 4.0 out of a ranger between 90-92.

Wasnt tryign to ague with anyone. Just trying to learn a few things before I try and do this to my BII. Thanks alot guys.

 

[Javve]

Why not get a 4.0 out of a Bronco II? Think the non 4wd versions had it. I could be completley wrong.

I had a 4.0 in my ranger when it was given to me, siezed up sitting in the bed of the truck. I took a wiring harness from a Bronco II (90' with a 2.9L) then put that and the computer from it into the ranger. Then I got a 2.9L and Transmission, put it in, installed the wiring harness from the Bronco II from computer plug all the way around to the firewall plug. Changed out the air filter box, started it up!

I am looking at going back to a 4.0 myself. Hope the above helps you out. May be different using a wiring harness from a ranger into a Bronco II but not so much going the reverse route.

 

[LittleHorse]

4.0 was listed as an option in the BII brochure but to the best of my knowledge a factory production 4.0 BII has never been seen, 4x2 or 4x4.

 

[AllanD]

There were, if I'm correctly informed, exactly SEVEN 4.0 Bronco2's made.

NONE were ever certified for us sales, where the VIN tag was supposed to be was
an identical label stamped "Vehicle Manufacturer"

I've actually seen several retrofitted 4.0's in 1990 Bronco2's
But all have had the "T" engine code denoting a 2.9.

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