Writeup: 4.0 swap 94 Ex to 89 B2

Motor swap from a 1994 4.0L Auto Explorer to a 1989 2.9L Manual Bronco II

Original Poster: Dustin Ewers (disciplerocks)

Difficulty: 8 out of 10

Time to install: 1-2 weeks+ (depending on skill and prep)

Disclaimer: The Ranger Station.com, The Ranger Station.com Staff, nor the original poster is responsible for you doing this modification to your vehicle. By doing this modification and following this how-to you, the installer, take full responsibility if anything is damaged or messed up. If you have questions, feel free to PM the original poster or ask in the appropriate section of The Ranger Station.com forums.


I advise you to do a thorough tune up to your new motor. Clutch (if applicable), plugs, wires, pcv, air filter, oil, oil filter, antifreeze, ps fluid, fuel filter, serpentine belt, water pump, valve cover gaskets (please please go with permadry, don't use cork), oil pan gasket. If you have the money to go ahead and replace the oil pump. I didn't have the money to throw at one before my swap.

Since my donor had an auto in it, I kept my original FM-146 transmission. I ordered a new 4.0 flywheel, 4.0 slave, and 4.0 clutch kit to make it work with the new motor (I found out after that the 93-94 slave cylinders have a different fitting than the earlier years so instead of buying a another slave and dropping the tranny, I chose to buy a 94 master cylinder and clutch line for a little over twice the price of a slave, but I didn't have to drop the tranny again so it was worth it to me.)


The Donor:


The Recipient:


First thing if you are pulling from a running vehicle. Remove fuel pump fuse, or hit the fuel cut off switch. Start it and let it run lines dry.

Disconnect and remove the battery.

Drain radiator, oil, and ps fluid.

Remove radiator, starter, a/c lines, power steering lines, cruise and throttle cables, fuel lines, vacuum lines.

Return bolts to original hole after removing any brackets or whatever so you know where they go and don't end up with a pile of unknown bolts at the end of your swap.


Remove and mark all plugs that are before the main harness plug, ie: MAF, alt, headlight plug


Disconnect two big plugs next to alt. This will let you keep the harness on the motor, on there.

Disconnect headlight harness on drivers side.

I am not going into any details about pulling and installing the motors. That is pretty straight forward.

Before dropping the motor in, swap the fuel lines from fuel filter to disconnects with your donor (I did this after the motor was in. It would just be easier to get to.) The disconnects at the motor are not the same between the 2.9 and 4.0.


Now on the filter end, the return line on the 2.9 is female, but the 4.0 is a male.


There are several ways to go about this. Here is what I did. I cut off the female end and slid it on the 4.0 lines and added a hose clamp for security. If you do this, heat up the metal line and slide the plastic over it. If you heat the plastic, you could deform it and may not seal. If you go this route, use a 4.0 fuel filter. The lines wil connect to the older one, but the nipple on the filter is not as long and you wont be able to get the removal tool behind it to remove later.

Also keep your existing line from fuel tank the charcoal canister unless you swap that out also. You'll have to extend the line from the TB to the canister if you don't swap them.



Pull the 4.0 engine harness. Everything should unplug until you get to where the distribution box meets the headlights next to the battery. Cut here keeping the alt, starter and solenoid harness. Others have used the 2.9 starter harness. I found that it didn't reach the 4.0 starter so I swapped it out. I also used the 4.0 alt harness. I had to cut one wire that went into the headlight harness, but I just spliced it to the same wire coming from the 2.9 HH. They were both a Grn/R wire. Pull the 2.9 harness the same way but dont cut the wiring yet. With both distribution boxes next to each other, cut the wires off the 2.9 box one at a time and wire them to the 4.0 box accordingly. I wired together the power doors, headlights, and interior fuse box. The EEC on the 4.0 harness (grn/red wire) needs to be wired to the ignition switch. I used one of the spare fused links in the distribution box temporarily to get it running. I could not get the fuel pump to kick on when wiring it to the 4.0 harness. Not sure where it ends up coming out at, but I ran a wire from plug on the driver fender (pk/bk wire) to the Grn/Y wire on the fuel pump relay. You will end up with a bunch of spare wires that you can use to fuse extra lights, winch, or whatever. I made a sheet with the wire color code and fuse location so I could identify them later. These must all be taped off since the box uses a common power, they could ground out. There is a 2 wire plug coming out of the harness near the battery also. One wire is black, the other is Bk/W. These must be grounded.





As far as the driver fender wiring, use The Bronc's diagram here:
http://www.therangerstation.com/tech_library/EDiagrams/files/BII4Lswapwiring.JPG

He swapped from and unknown year Ex to an 89 B2 so the wiring on the truck side was the same. The Ex side was also for the most part. One or two that were different, but easy to figure out. Also one of my plugs were brown and his description says grey.

I cut the connectors off both ends of the unused harness and did most of the splicing there so if I needed to remove it later it would be easy.


On the Ex auto harness I spliced together the R/Lt Blu and Pink wires in the cannon plug to bypass the neutral switch. I have yet to wire in my reverse lights. I'll update with colors once I do.

Make sure to solder your spliced wires. You don't want a short down the road that you have to track down.

Plug everything back in, hook up vac lines, install the 4.0 throttle cable, air filter, exhaust, fill it with fluids and fire her up. If you have cruise and want to swap that, just remove the cable from the 4.0 servo and put it on your 2.9 servo. Its 2 10mm bolts.


Here are some helpful links.

Other swaps:
http://www.therangerstation.com/forums/showthread.php?t=959
http://therangerstation.com/forums/showthread.php?t=32793

Trans swap:
http://www.therangerstation.com/tech_library/A4LDto5Speed.html
http://therangerstation.com/forums/showthread.php?t=90798

Various Schematics:
http://www.explorerforum.com/forums/showthread.php?t=232576

And my photobucket with these pics plus some wiring:
http://s19.photobucket.com/albums/b152/grakk/motor swap/

I am also attaching a couple Explorer diagrams to the thread. There are 2 Bronco diagrams that can be found in my photobucket.


I should also note that I am still waiting on my clutch line so I have not driven it yet, but the motor starts and runs good. It took me a week to prep the 4.0 for install and 4 days from pulling the 2.9 to having the 4.0 running. Any questions you can PM me or reply here.

What Dustin doesn't state is that those 4 days down time was done during the week between the hours of sleep, work, and the G/F...If one had an entire weekend, it is possible to have it done in two days, possibly a long weekend...
SVT

Very true thanks. I only worked on this for 3-4 hours a day.

good work. thanks for writing this up!

No problem. I hope it helps someone else decide to take the plunge. There was really only one decent writeup that I found before hand and I hope to answer some questions he didn't touch on.

Good writeup.

disciplerocks said:

No problem. I hope it helps someone else decide to take the plunge. There was really only one decent writeup that I found before hand and I hope to answer some questions he didn't touch on.

Click to expand...

I've got a couple of questions.

1. Did you have power windows, and how did you wire them in?

2. Do you have a manual t case, or did the ex?

I had those two issues w my swap. I used a 94 ranger as my donor and it was 2wd.

Nice write up.

I have power windows. There was a wire going to the 2.9 distribution box labeled power locks. Just wired that in to the same on the Ex. I assumed either that or the interior fuse box would give them power, but honestly I haven't even tried to use them yet. Its been non stop rain here.

The Ex had an electric TC and mine is a manual. The TC harness was randown the frame, not through the engine/tranny harness, but since mine is a manual I didnt have to worry about it.

What? you did'nt swap out the dash?

No need. They are the same.

when i get that donor explorer after i take the axles from her and put in the b2, i am really going to think long and hard on the 4.0 swap, maybe ill buy ya a plain ticket to come out and help me with it lol

i have a question were u cut the wire harness i didnt now do i still have to move the pegs around

What do you mean?

Pull the 4.0 engine harness. Everything should unplug until you get to where the distribution box meets the headlights next to the battery. Cut here keeping the alt, starter and solenoid harness. Others have used the 2.9 starter harness. I found that it didn't reach the 4.0 starter so I swapped it out. I also used the 4.0 alt harness. I had to cut one wire that went into the headlight harness, but I just spliced it to the same wire coming from the 2.9 HH. They were both a Grn/R wire. Pull the 2.9 harness the same way but dont cut the wiring yet. With both distribution boxes next to each other, cut the wires off the 2.9 box one at a time and wire them to the 4.0 box accordingly. I wired together the power doors, headlights, and interior fuse box. The EEC on the 4.0 harness (grn/red wire) needs to be wired to the ignition switch. I used one of the spare fused links in the distribution box temporarily to get it running. I could not get the fuel pump to kick on when wiring it to the 4.0 harness. Not sure where it ends up coming out at, but I ran a wire from plug on the driver fender (pk/bk wire) to the Grn/Y wire on the fuel pump relay. You will end up with a bunch of spare wires that you can use to fuse extra lights, winch, or whatever. I made a sheet with the wire color code and fuse location so I could identify them later. These must all be taped off since the box uses a common power, they could ground out. There is a 2 wire plug coming out of the harness near the battery also. One wire is black, the other is Bk/W. These must be grounded.








in that were u cut and the distributer box i just pulled all of that and swapped them

So you swapped the headlight harness too? It can be done that way. I heard its not as easy to splice. You'll need the wiring diagrams for both vehicles.